Why are dog breeds so variable compared to cat breeds?

October 2, 2014 • 12:53 pm

This is a question for readers to answer. I have my own theories, but I want to hear yours.

Dog breeds (I’ll spell out “dog” this one time) are of course tremendously more variable than breeds of cats. It doesn’t matter what trait you pick: behavior, color, skeletal configuration, size, and so on—dogs are more variable across breeds than are cats. To take one example, using just weight: cat breeds vary only about threefold, from the 6-pound Singapura to the 20-pound Maine Coon. But among dogs, the range is 90-fold, from the 2-pound Chi*ua*ua to the 180-pound Mastiff.

(In nature, however, the situation is reversed. There are roughly equal numbers of wild felid and canid species—38 of the former and 36 of the latter—and each has been diversifying for roughly the same amount of time. Yet the size range among wild felid species is 173-fold—from the 3.5-pound rusty spotted cat to the 605-pound tiger—while the size range of wild canids is only 34-fold, from the 2.5-pound fennec to the 85-pound gray wolf.)

There’s a reason I gave you those facts, which may bear on the answer to your question.  Again, WHY ARE DOG BREEDS SO MUCH MORE DIFFERENT FROM EACH OTHER THAN ARE CAT BREEDS?

Be complete in your answer, and be aware of questions that may be raised to counter facile assertions.

I will pick the best answer, and the award will be a Jerry Coyne the Cat Keychain, a very rare item (I have only three):

Screen Shot 2014-10-02 at 2.46.36 PM

 

This is a high-quality thick plastic-laminated image, with my namesake cat (as an adorable kitten) shown on both sides, getting a belly rub from his foster mother Gayle Ferguson. The prize guarantees a frisson of pleasure every time you use your keys.

Leave your answer below; contest closes at 6 p.m. Chicago time this coming Sunday (October 5).

294 thoughts on “Why are dog breeds so variable compared to cat breeds?”

  3. I am roughly the furthest thing from a biologist, so excuse me if I spew total nonsense, but I always felt it had to do with their respective places in human society. That is, dogs had certain roles (guarding, herding, fighting certain wild animals in tunnels, etc.) while cats, due to the relative difficulty in training them, had no such niches, really. Cats certainly helped in controlling vermin, etc., but for that purpose, one cat was basically as good as another. Therefore dogs were purposefully bred to maximize their utility for certain roles, while no such selective breeding took place in cats (or much less). This led to certain dog traits being emphasized in certain breeds while cat traits tended towards the average.

    I also always thought this might have something to do with the idea that while we actively domesticated dogs as societal helpers, cats more or less domesticated themselves. Feel free to tell me I am full of domestic excrement of either variety.

    1. I’m no biologist either but it think the question has more to do with why is there so much genetic variation in the first place. Humans can only pick their preferred attributes to breed and exploit. They can’t create the genetic variation in the first place (e.g. you couldn’t decide to breed a purple dog, you could only notice that a particular individual has a slight purple tinge and decide to keep breeding for that characteristic and, perhaps, you might end up with a purple dog at the end of it).

    2. That’s what I was going to go for: that it’s not a biological question but rather an anthropological one. One might similarly ponder why Western music favors diatonic chromaticism but Easter music draws its roots from pentatonic scales.

      b&

      1. That’s fair, and I offer this with the relevant epistemic humility, but human breeding activities are no more or less ‘artificial’ than are the segregation of Darwin’s finches to different islands, are they? To draw upon the music analogy, it’s like wondering why there are so many varietals of music and not as many of screams–music fills more and varied roles within the “ecosystem.” Okay, that got really tortured, and I apologize, but I hope something of my point got across!

        1. Human activity can be very artifical in comparisson to natural selection. If we find the runt of a litter to have a charateristic we want to propagate, we will feed, protect, and provide medical aid to that animal. We will then find that animal a proper mate which may be well outside the local naturally available mates.

          1. Exactly. Breeding by humans radically changes the environment the species are living in. Of course, the species adapt the same way they would to any other environmental change, but changes induced by humans are qualitatively and quantitatively different enough from the changes encountered outside of human intervention that it’s very useful to make the distinction.

            b&

          2. Okay! This is exactly what I don’t get, and if you could explain it, I’d be thankful. How are evolutiuonary pressures applied via human intervention different? That’s where I am misunderstanding.

          3. Humans can apply essentially teleological pressures to a species. The ancient ancestor of corn on the cob, for example, was small and barely palatable. Its wild descendent remains basically unchanged in its original environment. But, in the human-controlled environment, we’ve created selective pressures for big and tasty ears because that’s what we wanted. And, indeed, most highly-domesticated species would very quickly go extinct without humans to preserve their environments.

            b&

          4. Okay Ben, I am pretty sure we’re talking a distinction without a difference here! I agree completely. Human intervention, in essence, creates a very specialized niche. I’d just argue that other highly specialized niches exist outside of human intervention.

          5. The difference is that human-induced changes in environment happen rapidly and the environments are radically different from those encountered outside of human interaction.

            b&

          6. I’d say the biggest difference is that natural selection can’t work on the basis of selecting traits that will lead to a desired outcome, while that’s exactly what we do with artificial selection. Natural selection is short-term, selecting traits based on how they work now, while artificial is long-term, selecting on the basis of what traits we eventually want. As Ben points out, this can result in greater change in less time, as the changes are being directed toward a future goal rather than being simply a matter of what works at the moment.

          7. I’ve wondered this myself: isn’t talking about pressures humans apply vs pressures applied by non-human means fallaciously anthropocentric? Aren’t humans part of nature?

            But then I came to the realization of what Ben and Pali wrote: that it’s useful to create a teleogical category and a non-teleological category.

    3. I second Aelfric’s opinion.

      Dogs were bred for many uses, whereas cats were/are bred mainly for pets and for vermin control. As such, a large variability in type is not necessary.

      Compare this principle to goats. Goats are used for milk,for meat, and for fiber. The three types, dairy type, fiber type, and meat type each display distinctive characteristics, which were selected for by breeders over the last two or three centuries. Had there been other uses for goats, probably more types would have been developed.

      Similar strains can be seen in cattle – dairy type and meat type, in horses – riding type and drayage type, and in sheep – meat type, wool type, and to a lesser extent, dairy type (the sheep dairy industry is largely confined to Italy). L

          1. For the record, I’ve met lap goats! They just grow up very quickly (maybe I should say they evolve in to normal goats in about a year).

          2. Try Nigerian dwarf goats. They stay smaller (and their coats aren’t nearly as course as those of pygmy goats).

        3. Actually, if I’m not mistraken, the same goats that Linda raises (for milk) are popular as house pets, and as happy on laps as any medium-size d*g.

          Indeed, President Shrub was reading a particularly weighty tome on the subject when he was informed of the attacks on 9/11, and the book was so engrossing that he had to finish it before he could return his attention to affairs of state….

          b&

          3. You’re right! I think it was our illustrious former Ontario Premier, Mike Harris, who said the last book he had read was Mr. silly…(Diana?). But didn’t W have his book upside down?

        4. There are two breeds of small goats, a dairy breed, Nigerian Dwarf, and a meat breed, Pygmy. In Africa, they are working breeds, but in the US, they are mainly raised as pets. L

          2. I hand raise all my kids, and there are very good reasons for doing so.

            Pasteurized milk prevents the spread of CAE. Also, hand raised kids are easier to train to be milked, to be led, to have their feet trimmed, and just to generally be managed. L

    4. I’d also guess that considering that cats are generally much more difficult to train than dogs and keeping even the largest dogs enclosed in yards is usually not to difficult with a good fence — at least if the dog isn’t inclined and able to dig its way under the fence. Probably no breeder had any inclination to breed a domestic cat that could grow to the size of a small leopard never mind an Amur tiger. Even small cats are difficult to contain within an ordinary fenced yard and even a domesticated large cat could be very dangerous, as are many “domesticated” large dogs.

      1. Adding to my above reply, I regularly jog in my neighborhood and regularly pass at least one yard containing two big dogs who go into barking fits as I pass by, even if I’m on the other side of the street, and would likely try to rip me apart if they weren’t trapped behind a standard wire fence. A big cat could jump over that fence and pounce on me in seconds if it was inclined.

        1. Similarly, in my neighborhood, cinderblock fences are standard, ranging from six to eight feet depending on grade — a fence with a level top might start at six feet at one end of the property and be at eight feet above ground at the other end.

          Few dogs could scale these fences. Few cats even recognize the fences as barriers — and these cats are a fraction the size of the dogs. And a puma would be up and over such a fence even faster than an housecat — assuming it didn’t simply leap it in a single bound.

          b&

          1. A lot of dogs can scale the fences but don’t know they can. I’ve been very careful teaching my dog jumping because she could totally jump the 5ft fence I have. Same with horses – they could easily jump their fences but think they can’t.

          2. Rather than go for the obvious cheap shot about the relative intelligences of cats and dogs, I’ll observe that cats are superlative climbers. I’m sure I’ve mentioned this before, but the weather is finally tolerable here now and so I’ve been re-reminded of it…when I’ve got the front door open but the “security” screen door shut, Baihu will either vault off the screen door to the top of the main door where he’ll perch, Snoopy-stye, or he’ll just walk up the screen door. Dude’s an amazing athlete.

            Somehow, I don’t think you’ll be able to get a dog to do that sort of thing….

            b&

          3. I had a dog that used to sit on the roof of an old car when it got snow on it. My dad had a dog that used to sit on the roof of his house.

            Dogs (at least large dogs I’ve owned) tend to be good jumpers but not climbers. I had a dog that used to jump out the second window in a door (the window was missing that summer) and over the deck to land on the ground. Problem was, when we replaced the window, he didn’t realize and jumped through the window, breaking it and surprisingly not getting a scratch on himself. That dog was a pretty dog and a kind dog but he was dumb. My two other dogs would engage in bad things like going to the neighbour’s yard. They’d sneak off and come home and look innocent while this dog would be left behind at the neighbour’s and get caught. Poor guy.

          4. I think the combination of both jumping and climbing is very important in the superiority of feline physiology. Many species can jump, and many can climb…but, offhand, I can only think of two that can do both: cats and humans. And both dominate the tops of their respective food chains.

            b&

          5. Humans jump and climb poorly and what about goats? They can jump and climb and they aren’t at the top of their food chain.

          6. Um…because they’re tasty…?

            But, whilst goats are great at climbing cliffs, I don’t think I’ve seen them do too well in the trees. Humans and cats both do quite well in the trees. And humans climb cliffs much better than cats…really, you’re not going to find a better all-around athlete than an human, even if it’s easy to find examples that easily best us in any single category other than long-distance running. Humans and cats can both swim, but humans can dive. Other primates can climb trees better than us, but they can’t outrun us, and I don’t think any are as good at jumping as we are — and I’m pretty sure we’re the only extant primate that can swim, let alone dive. The only other animals that can throw things are also primates, and they can’t hold a candle to humans. We don’t have the best daytime vision or the best nighttime vision, but our nighttime vision is generally better than those with the best daytime vision and our daytime vision better than those with the best nighttime vision. And so on.

            In many of these categories, cats are our only real competition….

            b&

          7. “What a piece of work is a man, how noble in reason,
            how infinite in faculties, in form and moving,
            how express and admirable in action, how like an angel in apprehension,
            how like a god!”

            Shakespeare
            Hamlet, Prince of Denmark, Act II, Scene 2

          8. It’s amazing — and depressing — how often one might have what one thinks is a novel thought, only to discover (or remember) Shakespeare (or, on matters theological, Twain) putting it more eloquently than you could ever hope to….

            b&

          21. ah, dammit, sorry about the embedding. It’s frustrating that it just happens automatically with certain links with no apparent rhyme or reason, and no way to preview.

      2. This reminds me of what Jared Diamond wrote in Guns, Germs & Steel, of how some species are easier and harder to train (herding cats, anyone?), like horses and zebras, living in different social groups, are “predisposed” in different ways to being handled by humans.

  4. My uninformed guess is that human breeding of dogs over thousands of years to use for various purposes (including fashion) led to the diversity of breeds. As far as I know, human breeding of cats was not as prevalent.

  5. Answer #1 (da serious one): longer domestication time combined with more varied breeding objectives. Dogs have been bred to be trackers, pointers, retrievers, weight-pullers, guards, large-animal hunters, small-animal hunders, probably numerous other purposes I don’t know about, as well as for ‘cute toys’. Cats have basically been bred with only two goals in mind: to catch vermin and as cute toys.

    Answer #2: because dog breeders are still searching for perfection, while cats have already achieved it.

  6. I think it’s because people have domesticated and bred dogs over thousands of years for so many different purposes: hunting all kinds of species from bears to badgers, guarding, fighting, racing, herding, retrieving, police work, lap sitting, and so on. Cats have been used for mouse hunting and pets, and that’s about it. You might say this gets it backwards because the variability of dogs is what makes them suited to these different roles, but I don’t think so. The innately independent character of cats makes them unsuitable.

    1. The variability of dog breeds is quickly lost when random breeding occurs.

      A place I lived several years ago had a large feral dog population, started, no doubt by dumpoffs. One of my neighbors, who had lived in the area a lot longer than we did, commented that although they started out looking pretty different, over a period of time they all had that “mutt” look. L

  7. I would guess that dogs are bred (artificial selection) to do useful things, resulting in a lot of physical variability to fulfill one specific useful thing (in one breed of dog) versus another useful thing (in another breed of dog).

    Cats, on the other hand, serve no useful function and cannot be persuaded to do so. Therefore, there is no evolutionary pressure to adapt their physical characteristics.

    1. Cats are extremely useful in vermin control.

      This is most especially important in food areas, where the use of poison is extremely undesirable, and traps are labor intensive and largely ineffective. L

      1. As a claim about history, this may be right, but I find it hard to square with modern cats, which in my experience are lousy at vermin control – no match for a good terrier (or even an indifferent one).

        1. Depends on the cat. I used to have one that was a very efficient rodent predator — and she always shared the choicest parts with me by leaving them on the door step. If she detected an active gopher, she would sit still by the burrow opening until the gopher came out far enough to be grabbed. She would always share the head.

          1. Good point, and in fact, our current cat – now that I come to think of it – was very good at catching and dispatching rabbits at our old house (she didn’t make much of a dent in the local rabbit population – but then, what would?). In Australia, cats have a reputation for decimating wildlife; we were lucky to have a cat who turned all her fire on imported pests. Some of the rabbits she brought down looked as big as she.

            (And she also provided a service to our dog; she ate the rabbit’s head, then allowed the dog to claim the rest.)

            However – it depends on the dog, too. Have a look at the canine world records for ratting (we’re talking triple figures in less than 10 minutes), and then tell me if any cat could even get close to them.

        2. My last cat, Spike, caught mice with regularity and large rats from time to time, really earnt his kibble.
          No cat now as wife is allergic.

    2. Cats, on the other hand, serve no useful function and cannot be persuaded to do so.

      On the contrary. Were it not for cats, our ancestors would have starved. The cats ate the vermin that ate our grain stores. Dogs may have helped hunters, but cats enabled agriculture, and thus civilization.

      There’s a reason the Egyptians, at the forefront of ancient agricultural advances, worshipped cats and not dogs….

      b&

  9. “WHY ARE DOG BREEDS SO MUCH MORE DIFFERENT FROM EACH OTHER THAN ARE CAT BREEDS?”

    Because humans feel they can distort dogs to their own purposes much more than they can cats.

    But I cast my vote for William Dickson’s answer. 🙂

  10. One thing that just occurred to me: controlled breeding of dogs is, relatively speaking, dramatically easier than that of cats because dogs aren’t the escape artists that cats are. Therefore feline populations would tend to have much freer interbreeding so it would be more difficult to breed for specific traits than dogs. Also, cats worldwide have historically been employed to do pretty much the exact same role that their wild progenitors did, while dogs have been bred to do quite a variety of different tasks than wolves.

    On a side note, I have to wonder if the difference in the amount of time that the two species have been domesticated has anything to do with it- I’d guess that it wouldn’t be too significant since as far as I know domestic dogs didn’t really begin to diversify until humans began switching from nomadic/semi-nomadic hunter-gatherer societies to sedentary agricultural societies and that’s about the same time that cats were domesticated.

  11. This should be easy: dogs work for us, or at least historically we tasked them with jobs and consequently we applied more pressure to their breeds to select for certain traits.

    As a 6 cats household (7 with the latest stray that is showing up on the back porch) I can attest that I don’t have many jobs for my kitties to do, other than snuggle up and purr when either I or them feel like it. (usually, those times don’t cross often, but they cross often enough).

    Did I win?

  12. WHY ARE DOG BREEDS SO MUCH MORE DIFFERENT FROM EACH OTHER THAN ARE CAT BREEDS?
    That’s worthy of a treatise – no time, dogs demanding a walk.

    Why are dogs the size of say, a Yorkshire Terrier (under 5 lbs) of equal intelligence to, say, a Mastiff (175 lbs) with comparable differences in brain size? Convolutions? Are there other mammals with similar vast size differences and similar mental abilities?

    No invidious comments, please, from those felinophiles who refuse to put dogs’ and cats’ intelligence in the same sentence.

  13. Two components could in principle account for the greater morphological diversity of dog breeds when compared to cats. Either there was a lot more genetic variation captured when dogs were domesticated from Wolves. The fact that dogs were domesticated multiple times and often interbred with wolves would seem to argue for that. Only a comparison of the genetic diversity of domestic cats and dogs can resolve this question. Alternatively (or in addition), the selective pressures on dogs were very different than those applied to cats and led to greater diversification. Domestication history seems to support this notion. Cats were mainly kept for two reasons: catching rodents (and other pests) and beauty. Dogs on the other hand served a multitude of different functions: hunting, herding, guarding, racing, food, and beauty (maybe less so). Much like in an adaptive radiation (eg in Darwin’s finches or cichlids) they filled many niches. These different selective regimes caused the morphological diversification of dogs; probably more so than the higher genetic variation, as it turns out that the genetic differences between dog breeds boil down to only a few genomic regions.

  14. Something just occurred to me…feral cats after sufficient generations tend to revert to the classic tabby patterning, with physiologies strikingly similar to the African wildcat they’re most closely related to. You could put Baihu in a lineup with a bunch of African wildcats and not be exactly sure if he’s the odd one out or not.

    Not only do I have no clue what feral dog populations would tend towards, we’ve essentially created new species of them. There’s no way that you can consider a Teacup Chihuahua and a Great Dane members of the same species, even if they’re interfertile with others that eventually meet up somewhere.

    Whether effect or cause, that’s gotta play into any considerations….

    b&

    2. My uneducated impression is that feral dogs kind of end up small to mediumish, short-haired, and brownish-yellow. It’s what I’ve seen in poor areas of poor countries from South America to Africa.

          1. Or like my Australian Cattle Dog (which used dingo as part of its starter stock back in the 1830s when it first was started to be bred for cattle herding over enormous cattle stations in Queensland).

      2. I am not sure that’s true, but I am no expert. Why? What about the arctic breeds used by (say) the Inuit? Aren’t they pretty close to the ancestor wolf-type?

    1. I’ll ask a question here. The obvious weakness of your answer is that you don’t deal with the question, “WHY couldn’t cats have a function.” Couldn’t they be bred to, say, hunt badgers (select on size and predatory ability), and so on?

      1. Dogs that are bred as hunters don’t usually kill their prey (by breeding?) but cats appear to enjoy teasing then killing (which I guess could be changed by breeding).

        Now this is one hell of a non-answer…lol

      2. With the exception of lions, cats are not social animals to anywhere the degree that dogs and their ancestors are. They hunt and prowl alone, and aren’t inclined to take direction from humans.

        1. Your exception should include domestic cats along with the lions. Domestic cats gone feral spontaneously form colonies significantly larger and at least as socially sophisticated as the prides of lions.

          b&

          1. Wolves and African Wild Dogs hunt cooperatively, relying on their endurance and group tenacity. Lions hunt cooperatively, too, but in an ambush mode. I doubt that colonies of feral cats (I’m imagining a little old lady with cans of Friskies) have the same cooperative hunting behavior, but I may be wrong.

          2. Ah — your imagination isn’t pointed in the right direction.

            Crazy cat lady colonies aren’t what I’m describing, but, rather, purely feral cats not dependent on humans at all, and often actively avoiding humans, for example on abandoned properties.

            There’s division of labor, shared hunting, communal raising of kittens, and all the rest, in colonies of dozens of members.

            b&

        2. Right.

          Encephalization Quotient:

          “Another factor affecting relative brain size is sociality and flock size.[15] Similarly, dogs (a social species) have a higher EQ than cats (a mostly solitary species). Animals with very large flock size and/or complex social systems consistently score high EQ, with dolphins and orcas having the highest EQ of all cetaceans,[3] and humans with their extremely large societies and complex social life topping the list by a good margin.[1]:

      3. Wolves are more highly social than the ancestors of cats, and are predisposed to follow “orders” from dominant individuals, as an analog to dogs later slavishly following the commands of their human “masters”. Juvenile wolves in particular exhibit traits like fawning and tail-wagging and barking, so that dog-like behavior can be produced by humans unconsciously altering developmental trajectories of wolves, so you end up with tame and obedient dogs as essentially juvenilized wolves. I suspect no such type of heterochronic change is possible with cat ancestors.

      4. Here’s my guess: When cats became domesticated, they already HAD a function, and because they are so good at it, and because it is so necessary, we were probably content to leave it there. Companionship is an added bonus.

        When dogs became domesticated, probably their main function was JUST companionship. If you start out with a wolf prototype, probably the first obvious function would have been protection. Moving on from there, they might have been trained to protect property and livestock, and branched out from there.

        Further, the size difference might be a factor. Larger dog breeds are mostly working breeds; smaller dogs are mostly pets, with a few of the smaller breeds having a working function. Breeding down in size is always easier than breeding up, so it would seem logical that the jobs dogs were bred to do couldn’t be done by an organism the size of a cat. L

      5. Ooohhh…I think you just gave it away, and it plays directly to a point I’ve made more than once, myself.

        Pound for pound, cats are far more lethal than dogs. A wolf can rip out a deer’s throat, sure, but a jaguar will pierce its skull with its jaws. Only cats give humans a run for the money in the all-around athleticism department…we’re both excellent runners and climbers and swimmers (in the cases of tigers and jaguars) and jumpers and the rest. Cats are the fastest sprinters there are, but no other animal can compete with humans at long-distance running. If cats could throw things and make tools, they’d be the dominant species, not us.

        A cat that could hunt badgers would be a puma; a dog that could hunt badgers would be a wolf. An human could dominate a wolf, but not a puma…the puma’s respect you’d have to earn and keep, and, even then, regular feline playing and signs of affection and communications of annoyance and the rest would be devastating to the human.

        b&

          1. Europen badgers are very cute, but they’re pussies compared to North American badgers. Any match between dachshunds and a N.A. badger would result in a lot of dead and maimed dachshunds.

          4. Where’s the mushroom part??? I did see that Croatians make badger goulasch…Which does not sound particularly appetizing, especiallt if the badger is still digesting a cobra – or puff adder.

        2. I think wolves can outrun humans for distance and sprint speed. Perhaps a top marathoner can run a marathon faster than an average wolf, but an average wolf can run a marathon every day.

          1. If we’re making this comparison, it’s only fair to make it not with modern domesticated lard-assed humans, but hunter-gatherers. And the most common widespread hunting technique amongst savannah-dewlling humans for bringing down large game, even to this day, isn’t with bow and arrow…but simply chasing the animal until it drops of exhaustion. At first, the animal will sprint away much faster than the human can keep up with, and then it’ll rest until the human catches up. The cycle repeats. With other predators, the predator can’t keep up the chase as long as the prey, and the predator has to rely upon either stealth and cunning or the coordination of multiple predators…but a lone human has the endurance to keep up the chase all day until the prey is too tired to run or fight, at which point the human has an easy kill.

            Of course, this hunting skill is as atrophied as all other primitive hunting skills, such as flint napping. But there are still a few tribes that use it to this day, and it used to be how we got our daily…meat. And likely much more commonly so in the days before distance weapons and traps and snares.

            Cheers,

            b&

          2. I’m completely unconvinced. Modern atheletes are hardly “lard-assed humans”. They are selected from a very large pool of individuals – most of whom, admittedly, are lard-assed. But I strongly doubt that you could find anyone in one of the few remaining hunter-gatherer societies who could perform at the level of a professional athlete who is in top condition and whose food and health care are incomparably better – much less at the level of a wolf who can travel 50 miles or more each day in search of food – most of that at a trot. The hunter gatherers best the wolves because they combine good endurance with brains and tools.

          3. My own Congressional Representative, Kyrsten Sinema, has done an Iron Man Triathlon, which is the equivalent of a 75-mile run, and she did it in just over 15 hours. She’s emphatically not a professional athlete, though she’s certainly fit and dedicated. Hell, a year ago she couldn’t even swim! And she’s not a spring chicken, either; she’s in her late thirties.

            The true serious elite human endurance athletes will do 300 km / 190 miles in 24 hours, or even 400 km / 250 miles in 48 hours. Yiannis Kouros ran a thousand miles in just over ten days, and an hundred miles in under twelve hours. Maybe your wolves can manage that, but I rather doubt it.

            b&

          5. Something for you to research in your spare time: “Man versus Horse Marathon”.

      6. The other obvious weakness of my answer is that if cats are not constrained by function, their appearance ought to be more malleable, not less.

    3. Companionship isn’t a function?
      My black kitty Reginald won’t hunt anything but spiders, but he is a loving and beautiful companion, and that’s enough for me (and apparently was enough for the people who bred his ancestors a couple thousand years ago).

      1. Companionship is a function, but, no, it’s not enough in a primitive society.

        If an organism wants to be your companion, but it’s costing you scarce food to have that companionship, then you’re going to be not disposed toward it, no matter now pleasant it might be.

        OTOH, if companionship comes in addition to protecting your food from predators, then so much the better. Imagine finding out that this potential companion is protecting your grain stores from rodents!! Wow!! L

        1. Exactly! In ancient times, cats performed a vital, irreplaceable service for early farmers — keeping vermin in check — and the most they asked for in return was a warm fire and / or lap to curl up to on a cold night. How could we not repay them with eternal gratitude and worship?

          Dogs, on the other hand, for all the valuable functions they perform, still need to be fed and cleaned up after and cleaned and generally cared for not unlike a perpetual child.

          b&

          1. Yes, I’m sure that the millions of blind and otherwise disabled people around the world who owe their freedom and independence to their beloved dog companions surely must feel terrible that the trade off for such freedom and independence is to feed them every day and perhaps take them outside to do their business.

        2. I agree, but as far as we know, dogs were domesticated by hunter-gatherers (presumably nomadic at least some of the time), while cats are thought to have been domesticated by people who already had agriculture (and additional domestic animals). Food competition would have been an issue in both cases, and I think it’s entirely possible that early domestic cats were eaten by humans during hard times, just as dogs were.
          But cats would have been valuable in other places besides the granary. They would have cleared the vermin (four, six, eight, and umpteen-legged) out of the house, too.

          The human-companion animal relationship is complicated. In Sierra Leone, people are abandoning pet monkeys for fear of ebola transmission (though they also eat monkeys as “bush meat”). The monkeys compete with humans for food, and though they may have some practical uses, they seem to be kept mostly as pets, even by people who are struggling to survive.
          http://news.yahoo.com/pet-animals-become-victims-ebola-scare-ivory-coast-040447897.html

  16. I think most of the commenters have it right. Dogs, through most of their history of domestication, have performed various specialized jobs and have been bred for those jobs. Cats have performed only two jobs: mouser and lap-buddy, and nobody was applying divergent artificial selection to them until quite recently.

    Now, lately a lot of the selection applied to both species has been purely for appearance, as a kind of artwork. We are starting to see weird cats: hairless ones, bigger ones, weird ear shapes. Give it another hundred years and see what cat breeds look like. But dogs are still starting from an advantageous position there, as any new standard of cat appearance must be established (or have good prospects of establishment) before breeders will aim for it, while dog standards are all over dog morphospace.

    It might be that cats are inherently less evolutionarily labile than dogs, but I don’t see any strong evidence of that so far. Felids and canids don’t seem radically different in their behavioral and morphological disparity, or at least that’s my impression.

    1. By the way, I type this with a cat sitting on my chest. Not the easiest thing to do, and all typos are her fault.

  17. There is a wonderful book “Cat Sense: How the New Feline Science Can Make You a Better Friend to Your Pet” by John Bradshaw that explains some of these aspects. Most interesting is how d_gs have been bred for doing a job, while cats have not. Cats have been only recently bred for looks. Bradshaw points out that if we wanted to breed cats to be more social, not only with humans but with other cats et. al, it would not be difficult. But we have not been consciously breeding cats for behavior – although we have unconsciously bred some of their characteristics. I highly recommend the book, and there is one for d_gs too.

  18. The difference in variation is a result of the fact that dogs were bred for many different purposes, while cats were not. I don’t know of any purpose cats were bred for other than catching mice and similar vermin, and being companion animals. Dogs, on the other hand, were bred for a multitude of purposes: Pulling sleds, going down badger holes, herding sheep, racing, tracking, retrieving, fighting to the death, etc.

    Obviously, dogs bred for specific purposes were bred to an appropriate size for the task. But in addition, as dogs were selected for behavioral characteristics, additional physical variations appeared as a result. This is explained in the following video, which discusses the domestication that was done with foxes, starting in the 1940’s:

    http://www.youtube.com/watch?v=RJn0BWlERRw

    Go to about 35:00 for the section on the foxes. The part about how selecting for behavioral traits resulted in unexpected physical variations begins at 41:45. Of course, once the physical variability in dogs was apparent, people appreciated the variations and sometimes bred for physical traits instead of behavioral ones, which added to the overall variation of dogs.

    Note: The video I linked to above appears and disappears from youtube frequently. I recommend you watch it while you can.

    1. I see you replied to another answer with this question:

      “I’ll ask a question here. The obvious weakness of your answer is that you don’t deal with the question, “WHY couldn’t cats have a function.” Couldn’t they be bred to, say, hunt badgers (select on size and predatory ability), and so on?”

      I think one reason is that the pre-domesticated dogs were probably fairly large, which would have meant they already had enough size to do things like pull carts, manage sheep, and so forth. The pre-domesticated cats were probably much smaller than those first dogs. The cats would have had to be bred to be much much larger to do such tasks.

      Also, the pre-domesticated dogs probably had social instincts that made them easier for humans to work with than pre-domesticated cats. They probably lived and hunted in packs, for example, while the cats did not.

      1. Dogs being pack animals respond to an authoritarian better (dogs are the religious fanatics of the animal kingdom). Cats, not really evolved for pack hunting and living more solitary existence are less inclined to do things for the betterment of the group (at the expense of others). Cats are more the skeptics of the animal kingdom.

      2. You could also explain it by incumbency. Cats were domesticated long after dogs. By the time cats were available to do various tasks, there were already dogs doing them, so why begin the long process of breeding? Cats did the job they were already best suited for: catching small rodents.

  20. I have to imagine that it’s due to the fact that dog size is controlled by very few genes. That combined with artificial selection has increasingly isolated these in domestic dogs. It is furthered by continued breeding for smallness, further selecting for the gene/mutation responsible for small size.

  21. The comments of “because dogs were bred to specific purposes, and cats weren’t” isn’t an answer, it’s merely a restatement of the question. WHY is that the case?

    I suspect it has to do with the fact that cats are self-domesticated, far more so than dogs. Wild wolves may have performed a bit of self-domestication, learning to tolerate humans to the point that we were then able to mold them into diverse forms. They may have, by accident, picked up subservience to humans along with reduced aggression and more juvenile traits. Cats, however, seem to have approached humans as roughly equals. They self-domesticated because our odd habit of storing grain attracted rodents, so they had to get used to us being around. And they too evolved to retain their meowing and be less aggressive, but dodged the subservience trait.

    In short, dogs survived by becoming servants to humans. Cats survived by becoming partners, thus retaining more control over their own path. (Not conscious control, obviously, but I think you get the idea.)

  22. I think that it has to do with the utilitarian value of d*gs and cats. Cats’ practical uses are largely confined to vermin control. Their other qualities are largely aesthetic or emotional. D*gs are, on the other hand, bred for a variety of purposes. Toy breeds are unsuited to herd sheep, hunt or stand guard. Shih-tzus and chihuahuas are only suitable to terrify burglars who might step on them or steal thee purses they’re carried in. There is no real need for an adult cat that weighs only a pound or a mouser the size of a great dane*. Furthermore, the Cat Fancy, which has encouraged breed variation, has only been active for about a hundred and forty years. We have seen more and more varied breeds emerge in the last thirty years than were even in existence when the first cat shows were held. As a sometime subscriber to Cat Fancy magazine, I have seen, in more recent issues, types of cats in the breeders’ directory that never existed when I first started reading it in the 1970s. Perhaps in another hundred years, we will see the feline equivalent of mastiffs.

    *The four-footed one, not the piano-playng one.

  23. One reason is the great change in the shape of the canid skull during development. It starts out short and rounded, and develops a long, narrow muzzle. Therefore, the genetic groundwork exists for short, rounded, more neotenous (spelling?) faces as well as long, thin faces. Note that the variation in skull shape can include variation in brain shape/size, too.

    I’d put in a plug for the long time of domestication, too. We’ve been selecting for retention of juvenile features into adulthood (playfulness, floppy ears, life-long tolerance of subordinate position in the hierarchy, etc.) for much, much longer than we’ve been living with domesticated cats.

    What have we selected cats for? We want little rodent-killing predators that purr for us and can live in groups. Not much change. We’ve wanted a lot more behavioral changes in dogs.

    And it is possible (I hate to say this) that the ancestors of dogs, being social predators, were more intelligent than wild, solitary cats, providing a greater diversity of behaviors that humans could work with and change through both training and breeding.

  24. Dogs are psychologically obedient to higher ranks, i.e, the human owner. This obedience is the most important reason that we human select dogs as pets. So, it is OK to keep both the large and small size dog breeds, since dogs are obedient & royal to their human masters, they simply don’t attack their human masters.

    Cats are on their own free will. Their human owners are merely meal suppliers and playmates. At the beginning, cats might helped human by killing rats, but we sure don’t need a big cat such as a tiger to kill rats. Since obedience is not a character of cats, human just can’t control big cats, so large breeds don’t really have a chance to survive under human selection.

  25. I think it’s pretty much been said. Dogs have been domesticated for between 15,000 and 33,000 years ago.

    Although, I would also say that, judging from the distribution of both species, that the canids had a greater diversity even before domestication. Canidae includes the foxes and some fairly odd critters like the raccoon dog, jackals, various “wolves” which are pretty variable anyway.

    Cats, all modern cats, and a large number of extinct cats are still very basically the same animal. Of course, hyenas are felids too, so that’s kind of an odd man out.

    The point is that, in the cladogram with dogs is the gray wold (most closely related), the coyote (which is somewhat different morphologically) and the golden jackal which is very similar to a coyote-sized wolf. But also consider the environments. Wolves can handle very cold temps (up to the Arctic Circle IIRC) and coyotes are nearly pure desert dwellers.

    Felids are much less diverse along the lines that resolved to domestic cats. (Info from here: http://www.sciencemag.org/content/311/5757/73.short)

    Felis catus is most closely related to F. silvestris (the European Wild cat) and then F. libyca (African Wild cat) and then F. margarita (Desert cat). Those are all very, very similar morphologically. I mean, the African wild cat, except for slightly longer legs looks exactly like a cat that used to call my lap home. Same face, same ears, same markings.

    So, my idea is that (other than anthropological), there’s just less variation in domestic cats because their ancestors had less variability in their genetics.

  26. Is it because humans have been artificially selecting traits in dogs for thousands of years while cats have been artificially selecting traits (such as cleaning the litter tray and opening the food container) for less time?

  27. A bit tangential but there is a school of thought that canine domestication has also been directed at selection to preserve puppy-like features in adult dogs (floppy ears, etc) as there was a belief that this reduced adult aggression (tamed the wolf).

  28. I have always found this an interesting question. Some of my thoughts:

    1. Dogs have been bred for a wider variety of purposes than cats, and have been selected for more diverse and extreme physical differences in size, coat, face shape, and athletic ability. Cats are not working animals and have been selected primarily for color and hair length; breeding for characteristics such as ear shape and size, curly coat, and short legs is mostly a modern practice and still rare.

    2. When cats are bred for specific physical characteristics, genetic flaws (some fatal) accumulate within a few generations. Examples include Manx syndrome and susceptibility to certain illnesses. Dogs can apparently be bred to greater extremes with more success (perhaps due to greater genetic diversity?) I don’t know anything about dog genetics so the above is speculation based on the abundance of “freak” dog breeds that push the limits of what the canine brain and body can endure. Also, people are willing to accept breed-specific flaws (seizures, skin disease, hip problems, shortened lifespan) in dogs, but cats are expected to be physically perfect.

    3. On size difference in wild cats: Cats are carnivores and mostly hunt alone, while many canids hunt cooperatively and some can supplement their kills with carrion and/or plant foods. The felid hunting strategy is to stalk, dash, and attack, which requires different muscle development from dogs that chase their prey for long distances and attack as a group. Compared to canids, felids have poor aerobic fitness and their lungs are proportionately smaller, but their jaws are stronger for their size.

  29. I’m a little surprised that more people aren’t familiar with Gould’s theory on this (he championed it anyway, I can’t recall if someone else originated it). That adult dogs differ from puppies more than adult cats do from kittens. So there is more plasticity in development and more games to play with in terms of exploiting neoteny.

    This is also discussed here:

    http://en.wikipedia.org/wiki/Origin_of_the_domestic_dog#Neoteny_in_the_rapid_evolution_of_diverse_dog_breeds

    1. One place Gould writes about this is the essay “A Dog’s Life in Galton’s Polyhedron” in his 1993 collection Eight Little Piggies. In the essay he notes research by Robery K Wayne and Raymond Coppinger.

      2. BTW, I should point out that a major point of this essay is about apparent limits to traits that can be bred for, and is thus intended to argue against the theory, popular here, that dogs have just gotten more attention from breeders but that similar degree of variation would be found in cat breeds if a similar amount of work were put in to cat breeding.

  30. My guess is that it’s because dogs have been bred to work – to help people with many different tasks that require a big range of physical types. Cats have been used mostly just as mousers and companions so they’re more uniform. (Cats are lazy.)

  31. In addition to reasons listed above, I’ll add in

    1.) Large, dangerous cats would have been hunted or chased away. Only smaller and less aggressive cats would have been allowed to hang around the humans and their stashes of food — so selective pressure would have been for smaller sizes and skittishness. They probably remained mostly on the outskirts of the human cultural networks for a very long time, ignored and treated the way we generally treat squirrels.

    2.) The social pack animal structure of wild dogs — and their natural traits of dependence and obedience to the Leader — resembles human status hierarchies. Dogs are thus easier to train and adopt into human communities, thereby inviting deliberate breeding. Cats, on the other hand, do not really seem to “think” like we do. We would only have started considering them as potential pets or companions when we had more leisure (and/or more imagination.)

  32. I remember reading a theory that domestication often involves selection for neonatal traits like big eyes etc, and that there is more variability between a puppy and an adult dog than between a kitten and an adult cat, thus providing more differences to select from.

  33. My guesses:

    Control of breeding was historically much easier to do with dogs than cats. The tradition of keeping dogs contained is a long one- leashes, yards, kennels and so on.

    Keeping cats contained is basically a very recent phenomena. I believe this along greater social acceptance of strictly ornamental pets will encourage controlled and goal oriented breeding attempts. Already can see this with ‘munchkin cats’ ‘American curl’ and so on.

    Dogs are omnivores, they have acquired novel dietary genes which enabled them to thrive on grain based diets. Cats remain total carnivores.

    Dogs are naturally social pack oriented- with novel features absent in wolves such as ability to follow eye gaze and pointing gestures. Can this come up in cats in the same sort of degree? I’m skeptical…

    Ages ago, I read this theory that variety is easier to come by if there is a greater physical difference between the newborn and adult. The more change there is; the higher of chances for “tinkering” with the various genes. IMO there is a much lesser degree of difference between kitten and adult cat than a puppy and adult dog.

    It’s often stated dogs are the most diverse domesticated breed, but what about pigeons? There is an extreme variety in domestic pigeons- both physical and behavioral- including some breeds noted and selected for a very specific, single behavior- Ringbeater pigeons for example. As for physical trait examples- Barbary, scandaroon, shortfaced breeds and so on. There is a huge difference between newborn and adult in pigeons and also as for breeding control- the pairs are largely monogamous so there can be an aviary with more than one pair freely associating yet be reasonably sure of paternity of the babies.

    1. Cats remain total carnivores.

      Alas, “thanks” to kibble, poor cats, this is no longer true.

      The ideal food for cats is whole mice, crickets, lizards, and similar critters. This is impractical to provide for indoor suburban cats (and such cats have no more business outdoors unsupervised than dogs).

      An excellent substitute is a raw diet, either home prepared or commercially bought frozen; it’ll consist of whole animal parts, with bone and organs and skin and sometimes even fur, ground or chopped into manageable sizes. Baihu eats Nature’s Variety Instinct, mostly beef and venison — he hasn’t cared so much for the other varieties.

      An acceptable but less than ideal substitute is quality grain-free canned food.

      And dry food should be held as a last resort…water is an essential macronutrient for all mammals, and cats have very low thirst instincts because they normally get most or all of the water they need from the prey they eat.

      Even with commercial raw and canned foods, the food doesn’t have enough water in it to keep the cat healthy, and you can’t be sure that the cat is going to drink enough plain water to make up the difference. So…I add generous amounts of water to Baihu’s food bowl at mealtimes, and a very little bit of Trader Joe’s Tuna for Cats to the bottom of the bowl to entice him to lick it clean (which he does). As a result, he’s probably the best-hydrated cat in the Southwest….

      b&

      1. Do cats have genes for digesting starch? Dogs do and wolves don’t, IIRC. It’s an event akin to lactose tolerance in humans.

        It was my poor way of trying to say dogs in general might have been historically easier to feed than cats. Dogs can do okay on table scraps or even *mainly* grain based diet.

        To my understanding and you reinforce this, such a diet would be disastrous to cats.. Many of cats would have had to gather vital parts of their diet on their own.. which means they live on the free range while dogs can be chained up and fed only bread with occasional offal for however the owner pleases. Side effect: cats have freer mate choices, dogs not always so- aside from pariahs or instances dogs allowed to roam free and gaining access to others in breeding cycles.

  34. This has to boil down to relative levels of genetic variability in the ancestors of cats and dogs. The ancestral species of domestic cats was probably a small wildcat from, guessing here, Africa or the Middle East. So the size range of all wild cats doesn’t matter since all of our breeds came from only one species. This ancestral species may have been under selection for small size and other domestic cat-like characteristics for a long time perhaps from competition from some of those other wild cat species. I’d guess the wolf populations from which we derive our domestic dogs retained more genetic variation for some reason. Maybe less competition from fewer species in the area from which they were domesticated. Basically, you need the genetic variability first before you can artificially select for size or other traits as has been done in both species. This has to come from the ancestral stocks of each.

    1. “I’d guess the wolf populations from which we derive our domestic dogs”

      This is not a settled question. According to this, the genomes of wolves and dogs show that they evolved from a common ancestor, rather than dogs being domesticated from a few friendly wolves.

  35. Initially I thought that cats were just a lot less useful than dogs so they didn’t get bred for as many things, but why? And then I thought that a cat the size of a wolf would be terrifying, not cuddly but wolves aren’t pushovers.

    I think these answers puts the cart before the horse. Taking a step back, in “Guns, Germs and Steel”, Diamond makes the point that there are some traits which lead to a good domesticated animal (eg: doesn’t fight to the death when startled, doesn’t jump over fences). When these attributes line up people have taken advantage and put the animals to work wherever they could leading to a wide range of forms (eg: draft horses through to miniature ponies). I think cats probably hit a number of attributes making them suitable for domestication but have fewer of them than dogs making them less suitable for use as labour. Compared to dogs and wolves, cats:
    * don’t haul weight (dogs/wolves have more strength than small cats and a temperament to accept harnesses and to pull/carry. Even well-trained big cats won’t haul carts)
    * don’t run or walk long distances (dogs/wolves will do long distance hunts and migrate with prey)
    * don’t heel or follow a leader (just try taking a cat for a walk. With a few exceptions, they’re a nightmare)
    * sleep a LOT (dogs/wolves can be active for more of the day making them suitable for a hunting helper)
    * are not hierarchical (dogs/wolves will easily follow leaders)
    * react more aggressively when startled and may draw blood with their very sharp claws (dogs’ claws aren’t weapons)
    * have a “play” instinct which can make them very dangerous (perhaps inadvertently) depending on their mood. This is especially true of the larger cats who can do that much more damage

    I would imagine that with sufficient energy and time, you could probably breed cats to remove or reduce some of these issues but why should we when we already have dogs?

    1. To just finish – because dogs are useful for labour, there are more incentives to breed them for different tasks. Malamutes for hauling sleds in the arctic, sheep dogs for shepherding, terriers for hunting rats. Cats might show this sort of diversity if we put in the effort to diversify them over thousands of years, but it’s always been more rewarding to work with dogs and let cats be cats 🙂

    2. You mostly make good points, but some of your examples are off the mark.

      * don’t run or walk long distances (dogs/wolves will do long distance hunts and migrate with prey)

      Tigers and jaguars, and possibly others, have enormous territories that can be larger than entire Western American states, and will roam huge distances even over the course of a single day.

      * don’t heel or follow a leader (just try taking a cat for a walk. With a few exceptions, they’re a nightmare)

      Cats aren’t all that much different from dogs when it comes to going for a walk; it’s just that people expect dogs to “heel” and put lots of energy into training them to do so. Baihu was born a feral kitten to a feral mother and never got close to any human until he let me take him in at several months of age, and yet we go for walks. He enjoys sniffing stuff, just like a dog would, and I’ll let him do so. When other people aren’t around, he’s often eager to walk the trail. And, when he’s had enough walking or people approach, I scoop him up onto my shoulders where he rides along.

      I honestly don’t think there’s anything about him that makes him particularly well suited to going for walks; indeed, if anything, it’d be the opposite, given his kittenhood. I’m pretty sure that almost any cat, especially younger ones, would take just as well to talks given a similar slow acclimatization. (Take everything very slowly, starting with just the harness going on and coming off right away, then later leaving the harness on a bit longer, then a bit longer, then attach the leash…carry the cat to the back yard and right back in…get in the car with the cat at the beginning of the walk around the block and get right back out again, then after a few times of doing that, start the engine before immediately shutting it off and going for the walk…and so on.)

      I would imagine that with sufficient energy and time, you could probably breed cats to remove or reduce some of these issues but why should we when we already have dogs?

      Because cats!

      b&

      1. Tigers and jaguars, and possibly others, have enormous territories that can be larger than entire Western American states, and will roam huge distances even over the course of a single day

        You may well be right, but tigers and jaguars are totally unsuited for domestication so I can’t see how you would consider this a genuine objection.

        The question is not what is physically possible given enough focused breeding, it’s why humans haven’t put in that focused breeding. And I’m saying that nature gave us dogs required a lot less work and breeding efforts pay off faster. To try to get a house cat to make very long treks, you’re going to have to work hard because they aren’t coming to you pre-adapted, unlike dogs/wolves which were already doing these things.

        Cats aren’t all that much different from dogs when it comes to going for a walk; it’s just that people expect dogs to “heel” and put lots of energy into training them to do so.

        That’s not addressing my point. I said that dogs are much better at following leaders which in turn makes it easier to train them to heel. We’re co-opting an existing instinct in dogs, and whatever’s present in cats is far, far weaker. Yes cats can walk some short distances, some will even follow their guardians in a vague sense. But they won’t follow consistently or easily and when stressed they will typically flee or fight rather than seeking their “leader”. Because they don’t turn to us for direction, cats are a lot harder to train in general than dogs.

        I have never said that cats can’t walk or they will absolutely never follow people, just that they don’t have as strong an instinct which comparatively reduces their utility as work-animals.

  37. The answer seems pretty obvious – dogs have been bred to carry out a large number of different functions (they are used as workers without pay save for food and shelter), whereas cats were originally bred as mousers and raters, and then for their beauty and characters. 🙂

  39. Someone may have already pointed this out, but I did not read all the entries above.

    D*gs have 78 chromosomes whereas cats have only 38 (which in no way implies that cats are in any way inferior.)

    78 chromosomes can combine in many more ways than 38 so you can achieve much more random variation of results. You can combine genes from parents in many more ways.

    I’m trained in maths, physics and computer science, so It is likely that I am barking up the wrong tree. (bad pun intended)

    1. To add to my evidence, mosquitos have only 6 chromosomes and I’m yet to see much variation between them, they all seem annoying and small.

      Goldfish (Carp) have 104 chromosomes and they have a very large variation under human selection.

      Fruit flies have 8 chromosomes and compared to Jerry Coyne I really have no experience so won’t comment on their variability at the risk of showing my complete ignorance in the matter.

      1. Interesting thought.

        So, other things being equal, more chromosomes means more independent assortment. Which means offspring will have a wider variance or genotypes/phenotypes, so directional selection can proceed faster. However, the ultimate limit on where you can take artificial selection (using existing standing genetic variation, excluding new mutations) does not change. You would still, eventually, be able to generate all the same genotypes with fewer chromosomes and more tightly linked genes, it would just take longer.

        1. If you take a simplified model, assuming all chromosomes are autosomes and not sex chromosomes and that no mixing withing chromosomes takes place (and that a d*g is a perfect sphere) then in a single mating for d*gs there are 2^78 combinations possible of chromosomes from each parent wheras for cats it’s 2^38.

          These numbers work out to: 302,231,454,903,657,293,676,544 and 274,877,906,944 respectively.

          As you can see, the difference is truly astronomical in magnitude, a factor of 2^40.

  40. Cats hate change. Dogs either do not care or can not tell the difference between variation. The flip side: dogs are probably the most unprejudicial species on the planet.

    1. Yes. Late to this one, I was going to post that cats are too obstinate to change, but expected that someone else had already beat me to it.

  42. I’ve often pondered this and I came up with a theory. Then, a few years ago, I opened my copy of Darwin to a random page, as I often do before sleeping (I keep a copy on my bedside) and was delighted to discover that Darwin had surmised the same idea! So, I feel pretty confident that the idea is a good one. I’ll let Darwin say it in his words:
    “On the other hand, cats, from their nocturnal rambling habits, can not be easily matched, and, although so much valued by women and children, we rarely see a distinct breed long kept up; such breeds as we do sometimes see are almost always imported from some other country. Although I do not doubt that some domestic animals vary less than others, yet the rarity or absence of distinct breeds of the cat, the donkey, peacock, goose, etc., may be attributed in main part to selection not having been brought into play: in cats, from the difficulty in pairing them;”

    It’s relatively easy to keep a dog within an enclosure. Have you ever tried to keep a horny cat inside??

    1. It’s relatively easy to keep a dog within an enclosure. Have you ever tried to keep a horny cat inside??

      Same reason why Jared Diamond guessed that humans didn’t domesticate zebras or kangaroos despite their other apparent advantages – they’re just too hard to control.

      The jokes about herding cats hits at this underlying truth. Even small cats can jump fences, climb tall trees and subvert attempts to corral & manage them.

    2. I think that if people thought it would be worth the effort, they could mate the cats they wanted. Difficult as it may be, it’s not impossible.

  44. Just thinking about this:

    Would anyone really want an 80 pound domestic cat? Dogs, as pack animals, will submit to their leader (owner) no matter how big they are. I wouldn’t feel safe trying to get a huge cat off my sofa. A large (Great Dane size) “guard cat” would be a very dangerous thing… even to its owner, I would think.

  45. Many breeds retain puppy like features as if some aspects of their development had been genetically arrested. This allows for more morphological variation than might otherwise be possible. I suspect something about their genome that is not found in felines makes that possible.

    I remember reading that when the Russians successfully bred tamer foxes, which are related to dogs and wolves (same family, Canidae), the effort yielded adult foxes with puppy like ears, an unintended consequence of selecting for genetically reduced adrenalin levels. Apparently, the genes that code for lower adrenalin levels produce other effects like different fur colors and the aforementioned floppy ears.

    Actually, if memory serves, the project wasn’t fully successful as the tame fox pelts weren’t suitable for the fur industry.

  46. Cats are bred more or less to serve two purposes: to kill vermin (they’re less dangerous than say.. snakes) and to look cute (they’re safer to pet than say.. snakes). And it’s only recently where cats have been bred to be companions rather than allowed to freely breed for mouse control. You can also convince them to not poop in the grain (unlike snakes). Recent breeds like hairless cats, dwarf cats and squish faced cats represent features that can interfere with killing mice but we breed for them because they’re cute.

    Dogs have been bred for far longer for a much wider variety of purposes. If we started breeding cats for pulling carts, guarding our homes, or herding sheep we might see much more variety in form in time.

    Come to think of it, do any other domestic animals we keep have such extreme differences in form as dogs do?

  47. Look, I have no idea, but I’m going to enter the lottery. My answer is in two parts:

    (1) The main reason is a variant of the “dogs are more useful” thing – but it’s rather circular to begin that way, because I think that wolves and African wildcats are probably equally useless, and variation in levels of usefulness among modern dogs is one of the things we’re trying to explain in the first place. A better way of putting it would be that wolves are more social animals, which can be more easily trained, making it easier for humans to assign a variety of different uses to them – which in turn results in a greater variety of behavioural and physiological differences among herders, hunters, ratters, house pets, and so on.

    (2) This only explains size, but does the fact that wolves are larger to begin with have anything to do with it? That is, if you shrink a wolf as far as you can go with selective breeding, then you’ve already got more variation in size than if you shrink a wildcat as far as it can go. And breeding for domestic pets is more likely to push size down than to push it up (as has indeed happened: mastiffs are less bigger than a wolf than a chihuaua is smaller, if you follow the grammar).

  48. many of the answers on offer don’t seem to be explaining why felids in the wild exhibit so much variability, but canids do not.

    1. Really? Canidae include the fennec fox, jackals, and the raccoon dog. That’s quite a range of sizes & shapes.

      1. Sire. Bit read Jerry’s OP – the variability is much, much grater in felids in the wild. Yet om the domestic front the situation is reversed.

    2. My answer doesn’t explain this, but doesn’t need to (and the same is true of many other answers). Like many people I’m guessing this has something to do with different types of artificial selection pressures operating on two paricular species (the wolf and the African wildcat). Facts about, and differences between these two species are all we need to appeal to. Any differences between the two different families these two species happen belong to are irrelevant. Or at least, likely to be irrelevant.

  49. Without reading other answers….I think the answer is some combination of the following:
    1. Dogs were domesticated earlier ( I think there is anthropolic evidence for this)
    2. After domesitcation dogs were dispersed much more widely. Larger gene pool means more variants to choose from
    3. Wolf behavior is more complex and maleable than cat behavior – most the the morphological diversity in dogs is based on a specific behavior.
    4. Possible but less likely- dogs were domesticated from a larger original gene pool than cats.
    5. Wolves are large and therefore have more uses that they can be selected for ( related to 3.)

    The more I think about it the more I think that 3 is the answer. I’d add the the first cats were probably great at getting rid of vermin but because of their behavior and smaller size they werent useful as ‘guard cats’ or ‘huntiing cats’ etc

  50. Because in the wild felines have been evolving by natural selection into many different species with a wide range of traits, while canines have not changed too distinct among species in the wild. So there is much more room for breeders to change canines than felines with selective breeding in a short period of time.

  54. OK, everyone else has put out the ideas I would normally lead with, so I’ll go with the wildcard, hinted at by the last comment as I type this.

    Cat breeds are, in fact, just about as varied as dog breeds for appearance, save one quality – size.

    Dogs, being absurdly obsequious to their human masters, can be trusted to remain safe at very large sizes.

    Cats, being largely indifferent to their human servants, can be trusted to become a mortal threat at very large sizes.

    Put another way, breeders trying for big dogs got big dogs, while breeders trying for big cats got et.

  56. I believe that dogs have been associated with humans for over 100 thousand years as evidenced from archeological findings in Africa. (citation needed) On the other hand, cats probably only became associated with humans about 10 thousand years ago with the advent of agriculture and grain surplus storage. Cats just moved in and did what they were already doing – killing anything that moves. People said, “Ooh, that’s cute.”

    It’s interesting that dogs seem to have accompanied humans as they spread around the globe. There are ancient sculptures of dogs from Peru and other ancient sites. No cat statues until Egypt, which is cat’s home town anyway.

  57. Observed natural variation suggests that both dogs and cats have sufficient standing genetic variation to allow artificial selection for a wide range of sizes and gross physical characteristics.

    However, it is not clear how much standing genetic variation exists in either species for fundamental BEHAVIORAL traits.

    In the case of cats, it is a common observation that big cats in the wild are scaled-up versions of domestic house cats, showing almost identical behaviors – body postures, stalking/hunting methods, sleeping all day…

    Now, setting aside the question of whether there is more standing genetic variation in the behavior of dogs than cats, the fact is that the NATURAL behavior of wolves, before artificial selection was attempted, was far more amenable to socialization with humans. Dogs/wolves are pack animals that understand hierarchy. Training for obedience taps into their natural instincts. If an animal is naturally amenable through training alone to obedience and socialization, that animal then becomes a prime subject for artificial selection for traits suited to a wide range of tasks.

    As for cats… well, to make a trivial point, before glass windows were common, you couldn’t even restrict their movements, so controlling their breeding would have been quite a task, even if it were desirable. And their natural behavior is much less suited to true socialization with humans. Cats cause havoc, and humans control the havoc only by restricting the size of domestic cats.

    Most cats are not pack animals. Although cats can be trained to some degree, they are never reliably obedient. Their “domestication” was really a process of cohabitation with humans for mutual benefit, rather than a master/servant relationship. And, although cats are no longer kept principally for vermin control, we still have literally billions of wild birds killed by cats every year. This suggests that it is extremely difficult, if not impossible, to breed hunting behavior out of cats. If cats are not reliably obedient, and you cannot easily breed out hunting behavior, then anything slightly smaller than a cat is a potential prey target. That being so, who would want a “domestic” cat larger than a few pounds anywhere near children or other domestic animals?

    1. I should add, in summary:

      Dogs and cats have been around humans for a long time, and cats probably also carry sufficient standing genetic variation to allow a wide range of potential physiological phenotypes. But genetic variation in behavior appears to be far more limited; and the natural behavior of cats is not amenable to socialization & training. So artificial selection of cats for a wide range of traits has never been attempted.

  58. Ceiling Cat was tired. He had created the heavens and the earth, light, stars, waters, land, vegetation, day, night, a bunch of animals to fly in the sky, swim in the ocean, walk and creep over the earth. But before He could rest, He wanted to create beings in His own image because Ceiling Cat thought that He was perfect and something so perfect should have a perfect likeness. He created these things and called them cats. Ceiling Cat looked upon His work and He was pleased for they were perfect like Ceiling Cat.
    Then Ceiling Cat said, ‘It is not good that cats should be alone; I want to make cats helpers to give them fusses and buy them nip. But who will help the helpers? I want to make dogs to help the helpers.”

    “However, I feel a sudden need to be in another room and don’t want to go to the trouble of creating these things fully formed; that’s a lot of work!” So, before Ceiling Cat darted off, He whipped up some wolves and apes and put in place some quick rules of natural selection, genetic drift, random mutation and such so that He didn’t need to mind the whole works.

    While things were taking place on earth, Ceiling Cat started to take a nice Ceiling Cat nap. However, just as He was falling asleep, a disturbing thought entered Ceiling Cat’s mind: “Where are Ceiling Cat’s helpers and where are Ceiling Cat’s helpers’ helpers?” Ceiling Cat started seeing Himself in an infinite regress and and it felt funny so instead of taking a rest, Ceiling Cat took some nip to even things out.

    In a few moments (things move fast for Ceiling Cat when He takes nip), Ceiling Cat saw that some ridiculous ape things had evolved according to the rules He set in place. Ceiling Cat laughed, for the apes amused Him.

    The apes were busy little things – they had already befriended His wolves. Ceiling Cat was impressed that such a silly looking creature like these apes (no fur and hair in weird places and they walked on two legs – hilarious!) could figure out a process to domesticate the wolves. He thought they’d screw this all up and Ceiling Cat would need to intervene via cattus ex machina.

    However, in no time, the silly looking apes had used artificial selection (sorta like Ceiling Cat’s natural selection) and dogs joined Creation. Their appearances varied as much as snow flakes differed (not really, Ceiling Cat likes hyperbole – suffice it to say there were a lot of dogs and they looked a lot different from each other) because the apes bred the dogs to suit the various tasks the apes needed them to do. Since the dogs made the apes’ lives safer and helped them hunt food, the apes lived longer and had more time to devote to giving the the cats fusses.

    Ceiling Cat was pleased at this and He purred, strutting back and forth with His head and tail held high.

    😸

    1. I do believe you’ve just won the thread. And now I’m kicking myself for not realizing the Truth of the matter earlier…I coulda been a contender!

      b&

    3. This doesn’t sound very plausible. There is no banishing, smiting, genocide or homophobia.

      1. Whoah. Have you ever looked at your paws, man? I mean, like, REALLY looked. They’re huge, man. They can scratch everything except themselves.

  59. The dissing of dogs here is jocular, and so doesn’t bother me, though I’m primarily a dog person. Love dogs, love cats, but can’t have them because they’d kill my birds. An inside cat would be ideal because I’m infested with mice. Thinking about it.

    “Do I contradict myself? Very well, then I contradict myself, I am large, I contain multitudes.”

    Walt Whitman

    1. But you can have the best of both worlds! An indoors cat who accompanies you outdoors on harness and leash. What’s not to love?

      b&

        1. I rather suspect a Maine Coon would be even more eager for walks than most other breeds. Go for it!

          (And, just a word of advice: from an early age, get the cat comfortable perched on your shoulders, which is where Baihu happens to be as I type. When you’re on the trail and the cat isn’t interested in walking, it’s much easier to carry the cat that way than in your arms.)

          b&

  60. You ask for theories but that is not possible; hypotheses yes but theories certainly not.

  61. It’s because dogs are team players. Dogs hunt cooperatively like humans do, and can be trained to help with hunting. The different dog breeds are mostly bred to assist with different kinds of hunting. Spaniels are gun-dogs, terriers go down rabbit holes, bloodhounds track by scent, dachshunds go down foxholes, and so on. Often they work in groups of dogs and usually under human supervision and direction. In order to create a dog more suited to whichever task its owner favours, they have been bred to different sizes and shapes and personalities. Dachshunds are long and thin for better entry to fox burrows, and Great Danes were used by German nobility to hunt bears and deer, hence their enormous size.

    Domestic cats, while more social than their ancestors, still do not have the skills to hunt cooperatively, and thus cannot be trained to assist humans with hunting different types of game. They can only do what they do, hunt rodents and small animals on their own; a useful skill but not one requiring huge variations in size. Cats’ main other role as companion animals was one they were already fitted for by size, they didn’t need to be bred smaller for it as dogs did. Cats cannot hunt socially so they cannot be trained to assist humans, so they stayed basically the same size; mouse hunting and lap-sitting size.

    1. terriers go down rabbit holes

      Ah — like theologians!

      dachshunds go down foxholes

      One wonders how many Dachshunds are atheists….

      b&

        1. Well, there’s our problem. We’ve been using terriers to hunt theologians, when we need to breed a new kind of dog better suited for the task!

          b&

  62. As some people above have said, the use of cats was not as varied as that of dogs, but this doesn’t really answers the question. We still need to know why they were not used for as many different tasks as dogs. My guess is that since cats’ behavior is more difficult to manipulate than dogs’, and dogs were available (dogs were domesticated before cats), there was little incentive for humans to breed cats for special tasks, which dogs could do with a smaller human effort.

  64. I don’t think this is a hard question. Domestic dogs show more variation because they were guided in their evolution by humans to have a function; to DO something (guard, protect, herd, retrieve, be companions and look a certain way). Cats, so far as we can say that they are domesticated (I have one who sometimes bites me as a greeting), were mostly bred apparently to BE something. Except as rodent control, the only function of cats is to serve our vanity. Cats in the wild are much more variable than their domestic cousins due to actually having to survive in their natural environments. I’m not a biologist and it may be that there are genetic reasons that the cat species humans chose to domesticate (or the one that chose us!)has less natural variability.

  66. LEASHES! If you can tie an animal to a post, you can control its choice of mates. If not, not…

    It’s been argued that one reason for monotony in domesticated cats is that until the age of navigation, just about all cats were within the range of wild Felis sylvestris, and introgression from wild cats slowed divergence in domestic [not domesticated!] from wild/feral optima.

    And cats may simply have less room for nonlethal morphological traits than ancestral dogs did. As an “owner” of a Manx, I note that her suite of skeletal divergences from the norm — not particularly great for a dgo — are sublethal to lethal in a homozygote.

  67. Because cats are as close to perfection as they want to be. And because d*gs are easier to breed (have you ever tried herding cats, let alone breeding them…?). Any possibility of a bottleneck in the domestic cat lineage, that didn’t occur with d*gs?

  68. I’m very to the game so I’ll go for the short answer. Humans train dogs but cats train humans.

  69. The correct answer has been hinted at, but I will put it more bluntly: cat just won’t let their servants choose their mates for them.

  70. Yes, dogs serve a wider range of purposes for people than cats. But how did that happen? Were dogs somehow more capable or more dexterous or adaptable? Certainly not.

    Dogs use their mouths to hold things and carry things, but so do cats (prey, kittens). Humans bred dogs to use their mouths for more different things. Why?

    I think it all boils down to the fact that the original wild dogs were bigger and more dangerous to humans than the original wild cats.

    As a result, humans kept dogs on leashes or in cages much of the time, whereas they didn’t bother doing that with cats.

    As a result, humans were better able to control which dogs bred with which. And that’s why humans ended up using more of their creative breeding techniques on dogs than cats.

    Semi-domesticated cats could come and go as they pleased, because humans were not afraid of them. Those cats mated out in the woods or wherever they liked, free of human control.

    Dogs needed to be controlled because their bite could kill a human. In contolling dogs for this reason, humans also ended up controlling their breeding.

  71. The answer is that over thousands of years cats have been carefully breeding the perfect human capable of opening cans, procuring catnip, giving rubs as and when required, etcetera. Humans breeding cats! The very idea is laughable

  72. Throw a bunch of dogs of various sizes into an enclosure and allow them to interbreed freely and come back in ten or 15 generations and you will probably find a population of medium sized animals with with medium length coats as freely interbreeding populations regress to a hybrid mean Thus, only the intense artificial selection caused by human intervention maintains the range of dog breeds A shorter experiment could be performed by surveying the mixed breed dogs at the local animal shelter. Cats, on the other have not been subject to intense selection for size and optimum body characteristics are usually conserved. One other interesting question is why melanism is common in domestic cats but rare in other members of the felidae.

  73. Without reading any comments, cats until recently have broadly always selected their own mates, retaining a ‘natural’ mix including the genes which are selected against by humans. Partly this is becauser they are smaller & less easy to control.

    Dogs have had their breeding far more carefully controlled, & as they have often been ‘working animals’ in a way that cats cannot be, being pack animals rather than lone animals like cats, they have been selected for traits to fulfil those roles. They are habituated to humans so that they will look when humans poit or where humans look where wild dogs or wolves will not.

    We all know that we select for less aggressive animals usually, which is why dogs often have puppy like characteristics & like other domestic animals, smaller brains & sometimes pied coats (feral pigeons exhibit the same feature so I suppose that might be linked to tameness??).

    1. I might add that now more cats are being kept indoors & breeders are controlling their mating, so there are cats with no hair, claws, oe with very short legs. Frankly I find breeding such characteristics abhorrent when they are for ‘human pleasure’ & harmful to an animal’s health.

      Anyone interested in dog breeding & genetics should take a look at the report by Patrick Bateson from 2010, which shows how enormously dog breeds have changed in the last century or so, as breeders have exagerrated unnatural characters such as the folds of skin on a bulldog or the shortness of a Dachshund’s legs:
      http://www.ourdogs.co.uk/special/final-dog-inquiry-120110.pdf

      He highlighted these areas of concern –
      “a. Poor management of bitches and litters in some breeding establishments.
      b. Widespread inbreeding.
      c. Selection for extreme breed characteristics which, over time, has resulted in the development of disabling anatomical and physiological characteristics.
      d. Purchase of dogs with behavioural characteristics that are unsuited to the environmental niche which the dogs are likely to occupy, namely that of the domestic household, or by owners whose lifestyle is unsuited to owning a dog.”

      By the way, Patrick Bateson is related to William Bateson, the Mendelist who coined the term genetics, & he is president of the Zoological Society of London.

  74. Previously I had submitted Darwin’s answer to this question; the tendency of cats for “night prowling”. However, while walking today I was pondering it some more and realized that there were a few recent facts that Darwin was not aware of.

    The “founding” species for ALL domestic cats is the same wild population and at the lower end of the size spectrum. In contrast, the founding species for all domestic dogs was at the higher end of the size spectrum. It is easier to breed down than it is to breed up in size as larger ‘pets’ require more resources. And hence we have pigmy goats, ponies, and I believe domestic sheep are smaller than their wild counter-parts.

    And what about ‘natural’ selection? Do founder species arriving on a new island tend to diversify down in size rather than up? Since smaller sizes require fewer resources, it would be interesting to examine if this tendency exists.

    Of course, this only explains the lack of variation in SIZE of the domestic cat, and doesn’t address the relative lack of variation in other traits (though, I suppose size variation could be a kick-starter for other traits as well). I still think we need Darwin’s “night prowling” to explain the relative lack of variation in other traits.

    1. Darwin’s actual words were “nocturnal rambling habits” but I think he also calls it “night prowling” in one of his letters.

      1. Well found! Chapter 1 p.42 for “On the other hand, cats, from their nocturnal rambling habits, cannot be matched” – but a quick look at the online Darwin archives & I could not see ‘night prowling’…?

    2. Oh & your size point – smaller animals often beget larger descendants on islands, while larger animals tend to dwarfism. Hence giant tortoises & pygmy elephants. But I am sure there are many many variables & it depends on who or what gets there first. You don’t see terrestrial mammals on remote islands very much, compared with reptiles or birds of course.
      For example…
      http://en.wikipedia.org/wiki/Island_gigantism

  76. Okay
    We domesticated Dogs from a wild ancestor, most genetic evidence suggests grey wolves. Up until 15000 years ago you wouldn’t be able to distinguish between the wild type and the domesticate type. Similar to Dmitri Belyaev experiment with silver foxes. Early genetic history of dogs suggest that it was from multiple pools of grey wolves and there was back crosses as well

    So it is only relatively recently that we have started having distinct varieties of dog. Each “breed” would be founded on a very limited number of individuals so founder effect may explain why there is such diversity.
    Unlike in the wild we have policed these islands preventing out breeding and further isolating the genetic material of that breed.

    So why not cats, I’m going with less diverse founder population as cats are not social animals as such smaller breeding group to begin with. Secondly they weren’t really domesticated they just chose to live with us until the revolution… sorry they weren’t domesticated easily and then once domesticated they weren’t breed to be anything other than pest control and house pet. So the question is could we play with the cat in the same manor as the dog has been? I don’t know is my answer

    http://genome.cshlp.org/content/15/12/1706.full
    http://www.vetmed.ucdavis.edu/Catgenetics/Feline%20Genome%20Project/Feline_Genome_Project.html#

    1. Stephen Budiansky in The Covenant of the Wild talks of animals ‘choosing’ domestication, & if human artificial selection is included within ‘Natural Selection’ as I would argue (humans being a product of Nature, their behaviour, however bizarre, must be ‘natural’), then domestic breeds are INCREDIBLY successful.

    2. I love the little homophone error with “manor”. You were thinking about the monarchic traits of cats, weren’t you? 😉

      1. Yes or I really can’t see my own mistakes with ease. I read what I think I’ve written rather than what I’ve written so I always farm out proof reading to other people.

  77. Q: “Why are dog breeds so variable compared to cat breeds?”

    As, almost all of them unsupported facile:
    1. Cats have domesticated us for half the time, or less, that we have domesticated dogs. (See below.)

    2. Humans have found more active uses for dogs – help in guarding communities and eventually hunting for them vs help in guarding farming products (which goes to partially answer #1, the time aspect ) – so have bred them more actively and in more places (hunter-gatherers and farmers vs farmers).

    3. Dogs are pack animals while cats are more solitary, so dogs interact more and stronger with humans.

  78. Only just joined this thread – I was out yesterday attending a full blown Catholic requiem mass for a cousin – bells and smells.

    There is one question that I haven’t seen in any of the comments: why is there so much genetic variability in the ancestral wolf that allowed such a range of breeds of dogs to arise? Are we seeing clues in modern dogs as to the origins of the wolf itself millions of years ago?

    I have no idea whether such variability exists in the African Wildcat that is, as yet, untapped by humans.

    1. I do not see why there should be more genetic variety to start with. Besides, how would we measure that? Wild cats are widespread through Africa & Eurasia, while wolves never pread to Africa but presumably used Beringia to get into the Americas. Geographically then there ia a good spread for both, so one would expect a good genetic variety perhaps…

  79. Several posts(5,8,25,33,34)touched on the reason with 41 nailing it, but Jerry wants to know why. Evolution seeks perfection in survival and predators survive by eating other animals. Cats are the ‘purrfect’ predator. Their shape regardless of size, their tools for killing, their cunning, their detachment, their ability to escape enclosure, in short all their qualities have evolved for one thing – predation. Purring could even express their contentment after a kill.

    Wild dog species lacked the detachment cats developed in their evolution. This made dogs more easily domesticated and changeable.

    Humans capitalized on the predatory perfection of cats when they allowed cats to stay around to catch rodents. The cats’ detachment kept humans from changing the cats with domestication and breeding. Cats are still not completely domesticated as dogs are even though they have evolved to accept our ministrations and seem to like it.

    Bottom line – a ‘domestic’ cat has a chance in the wild, but a dog has little chance unless it finds human contact. Cats are the ultimate predator and have little room for evolutionary change.

    1. Dogs often survive in the wild. In many developing countries, dogs roam the streets in packs; they are ferrel and dangerous to humans.

      An example of stray dogs can be seen in Moscow where the dogs ride the subways. The dogs for the Russian space program were chosen among the strays in Moscow.

      1. That is why I mentioned that a dog in the wild would need some kind of human contact to survive. A cat can survive on lizards, rats and small prey without the help of humans or our garbage. I have seen this in the country where cats go feral, breed and live without our help at all.

        BTW I like your Ceiling Cat Premise the best of all us! Thanks for giving me the opportunity to mention that.

        1. Thanks for my smart ass contribution. 🙂

          I think in developing countries those dogs are ferrel – living like coyotes do today. Eating whatever they find. Humans don’t have anything to do with them because they are dangerous.

  80. Forgive me it this post pops up more than once, I’m having WordPress issues…

    As far as the mechanics go for physical appearance, the DNA of dogs has “tandem repeats” (VNTRs), providing an enormous elasticity to the genome, whereas cats or cows do not… hence such a ridiculously varied body plan for dogs, while cats–no matter how much we breed them–look pretty much the same, and cows just look like, well, cows. I’m sure someone else will come forward who knows far more about this than me; I just picked this up from a Nat Geo Wild program several months ago.

    Google “tandem repeats dogs” and see what comes up. 🙂

  81. Interesting question, hard to answer.
    I am thinking that the answer could be, even partially to non-natural selection, a form of evolution where the “owner” of the dog or cat selects which puppy or kitten to be kept till adulthood or sexual maturity (and let them breed, see further).
    The dog, as the prototype – wolfs _ in nature live in packs, and the majority of the wild felines live a solitary life, (OK, the lions are not).
    As we know (?), the cats are tied to the PLACE where they live (territory), the dogs are more tied to the pack leader (humans) that to the place where they live.
    So when the humans moved to another place, the dogs came with them, the cats remained on the spot, thus they genes remained too.
    Humans used dogs for a various reason, for labor or for company. There were selected big dogs for bear hunting, smaller dogs for fox hunting, you got the idea. On the other hand cats had a much narrower use, for rodent control or for company.
    The simple answer would be: dogs behavior is leader (owner) oriented, they follow they leader to far places and breed there with other gene pools, dogs have been selected for various purposes, for hunting different games and for defense with multiple purposes or as a companion. Cats are more egocentric, territorial and they had been selected only for a few jobs, like rodent (rat/mice) hunting or as a companion.

  82. It seems that there are two classes of potential answers:

    1) That dogs have undergone a more intensive selection process.

    (This seems to be the most popular hypothesis discussed here.)

    2) That dogs have a higher mutation rate than cats,

    From my (non-scientific) observations, I’d favour #2 since there seems to be more variation in dogs than in any domesticated animal In other words it’s not that cats are unusually stable, more that dogs are more genetically plastic.
    Perhaps dogs are more susceptible to duplication mutations that permit dogs to survive mutations that would doom other species?

    1. The mutation rate is probably not what’s important. It’s standing genetic variation – i.e. the amount of non-neutral polymorphism present in the starting population. Artificial selection proceeds very fast compared to natural selection, and principally explores the phenotypic possibilities that are accessible by recombining existing genotypes. Artificial selection for a trait will stall when it exhausts that standing variation. Any further change must indeed wait for new mutations to arise – and this is usually too slow to be useful in mammals.

    2. #2 I think “plasticity” is a good way of describing a variety of genetic (maybe mutation rates, maybe the larger genome) and ontogenic factors.

      But I think it must be the *combination* of #2 and #1 – without #1, wolves don’t show the same differentiation, but presumably are similar as far as #2 goes.

      /@

  84. People are forever trying to breed the perfect d*g, so they constantly try to improve their (D*gs’) appearance, size, temperament etc..
    Cats, on the other hand, are already perfect.

  86. Well, let’s break this down.

    We’re not talking about skull variation here. A quick look at the skull of a Persian cat (http://www.catthevet.com/wp-content/uploads/2013/07/Persian-Cat-skull-variations.jpg) and the skull of a bulldog (http://www.angelfire.com/mi/dinosaurs/images/casts/dog_english_bulldog_skull_cast.jpg) will reveal that we’re perfectly capable of drastically altering the shape of the skull in both species. If the dogs have an edge on this one, it’s slight.

    Both species also have long-haired and no-haired variants, as well as substantial variation in coat color. So again, if there’s an edge one way or the other when it comes to fur/hair, it’s small.

    However, this is not true for body size. Jerry cited cats as generally ranging from six to twenty pounds, whereas dogs range from 2 to 180. There’s a drastic difference in the range of sizes, but it’s highly biased downward in cats. The smallest cats are close to the smallest dogs in size, but the largest cats are nowhere near the size of the largest dog.

    One major reason may well be that large cats are likely to be much more dangerous to humans. As a former cat owner (she passed away five year ago), I think it’s fair to say that at one time or another, most cat owners receive a serious scratch from their cat. A wound from a larger cat could prove fatal, especially prior to modern medicine.

    There’s also the matter of the hunting/”play” instinct. A large cat capable of hurting an adult could easily kill a small child, and it would be very easy for running children to trigger a cat’s reflex to chase prey.

    Well, perhaps these are reasons not to breed a large cat, but large dogs can be dangerous for similar reasons. Dogs have a similar chasing instinct, and a bite from a large dog could easily injure or kill a person. Yet, we have figured out ways to breed large gentle dogs like the Mastiff who are no threat even to small children.

    Here’s the key, I think. You can breed the hunting instinct almost completely out of a dog, and still have a useful breed capable of keeping watch, hauling wood or nets, etc. It would then be possible to take that nonhunting dog and breed for body size to get a large gentle dog.

    However, I don’t think there would be an incentive to do this with a cat. The primary purpose of a cat in ancient times was to kill pests attacking grain stores, though it’s slightly unclear whether we domesticated cats for this purpose or they domesticated themselves. Regardless, a non-hunting cat would not have been a useful animal to keep around. Cats are stricter carnivores than dogs, so it would have been extremely difficult to keep an animal that needed to eat other animals but was unable to catch them itself.

    So, I would say that reason we do not see the range of variation in cats that is seen in dogs stems both from the danger a large cat poses to humans and because breeding a house cat into a large gentle cat (a “catstiff”, if you will…) would require you to breed an intermediate type that would require its owners to procure large amounts of animal-based food while the intermediate cat itself served less of a purpose than its housecat ancestors.

    1. Some very good points there.
      I particularly like the observation that cats are much more specialised meat eaters than dogs, the latter being more omnivorous, less specialised.
      A large cat would not just be more dangerous than a large dog (remember, a large dog can accept you as the ‘leader’, due to its hierarchical social instincts), it would also require lots of ‘precious’/’expensive’ meat to feed a large cat. Not an economically attractive proposition.
      It would only have been possible after humans got organised in stratified societies with accumulation of resources by a few that could ‘waste’ meat on a large cat. Only quite recently, in other words.

  87. Variation in genomic/phenotypic plasticity in part as a result of their evolutionary histories. Dogs as generalists, cats as spcialists, approximately. Couple this with the differences that we as human selectors have sought to shape them deliberately into. Dogs – we have sought and strived for great variation, cats – not so much.

  88. There are various reasons, most of them already mentioned.
    1 – I think 50 (A DiLuca) points out an important observation: different cat species are/were already very specialized and might have less genetic variability than wolves to start with (that is a testable hypothesis, of course).
    2 – Wolves (and peye dogs) with their hierarchical social structure are very much more inherently domesticable than cats (cf. the conditions for domestication pointed out by Jared Diamond in Guns, Germs and Steel). Humans just have to ‘replace’ the leader of the pack.
    3 – Partly due to point 2 above, dogs have been domesticated very much longer than cats. Hunter/gatherers have dogs, cats were only domesticated with grain-based agriculture, about 10000 years ago, for rodent control. So dogs had a much longer time to fill the niches that humans created for them.
    4 – Once these niches were created and filled by dogs, there was not really room for cats to fill them, since we already had domesticated dogs to fill them. And even for more recent niches we had already very domesticated dogs to use for a new niche.

    Another point, maybe not fully relevant here, (although possibly related to points 1 and 2) is that dogs possibly ‘domesticated themselves’, by following humans.

    1. Of course, the last point might also be applicable to cats: where there were ‘heaps of grain’ rodents converged, and the cats followed their prey.

  89. A very different question is (Jerry, I hope that by this I do not infringe on the Roolz by switching the subject) why haven’t we domesticated and used rodents in so many functions and shapes as dogs?
    Rodents are known for genetic variability and high mutation rates, Why not a guard rabbit? Never mind Monty Pythons Holy Grail (killer rabbit), why not?
    We only use them as pets (‘good’), experimental animals (‘good’) or see them as vermin (‘bad’), why not more?
    Are their brains too small?
    I’ve been working (long ago, another life) with rats and rabbits, they are quite clever, sometimes incredibly so.

          2. And in the summer, take it for rides in my convertible. That would be the funnest of all. 🙂

        1. They seem clever and easy to tame. I’ve seen many in a zoo who were almost cuddly with their zoo keeper. People have kept monitors that are quite tame too and unlike crocs won’t up and eat you.

          2. I think the venom of their bite is nullified when they don’t eat decaying meat.

          3. Or maybe you should brush its teeth regularly. Good luck!
            One advantage of komodos over dogs & cats is that as poikilotherms they are much more economical in the meat department

    2. And while we are at it (digressing from the subject) there is a deluge of questions.
      Why are pigs -intelligent, social and high EQ-, only used for meat and finding truffles?
      Why did we never domesticated crows and kind: highly intelligent, High EQ, but not. Why only chickens and turkeys?
      Jared Diamonds criteria fall short here. Admittedly he was only referring to ‘big’ animals.
      Highly intriguing nnevertheless.There is no end to it, methinks.
      Note, my effort at 88 is hoping to obtain the prised rare award, not this contribution. This is just a small digression we hope the ceiling cat will allow.

  90. Here’s my take – just for fun – (I am not seriously competing and began typing with hundred or so comments less). It should only be read when more serious people, and biologists had their attention and one is truly desperate. My take is a variation of what Aelfric, 3 already pointed out.

    WHY ARE DOG BREEDS SO MUCH MORE DIFFERENT FROM EACH OTHER THAN ARE CAT BREEDS?

    The biological niche of humans seems very similar to that of the Grey Wolf (Canis lupus) once early humans arrived in the northern hemisphere and the ice started to melt. Competition, but also commonalities brought human and wolf/dog into an intense love-hate relationship.

    Humans bred the dog from the Grey Wolf and it became the companion that could fill “cultural niches” which opened up over time alongside the development of human culture. The savage wolf remained the untamed counterpart and the other side of the relationship and a symbol of evil (famously in the Grimm’s fairytales). They were driven away from human civilisations.

    Human and wolf are predators of larger game that hunt in packs. Both are endurance hunters that wear their prey down. Necessary social skills to coordinate a pack of hunters, hierarchies to determine who gets to feed first can be found in both species in a comparable or compatible way. And perhaps crucial, these traits have a use outside of hunting. It allowed humans to take the wolf with them through the ages and through the development of culture, and had a versatile animal to breed through artificial selection of appropriate animals.

    Wolves: Behavior, Ecology, and Conservation: Behavior, Ecology, and Conservation, p164: Wolf populations are composed of packs and lone wolves […] but packs form the basic units of population. Most lone wolves are only temporarily alone as they disperse from packs and either start their own pack, or join existing packs. (found with google scholar)

    Until the Paleolithic, humans were purely hunters but started domestication of animals at the beginning of the Mesolithic (~15.000 BCE). Lone wolves might have started to show up around early human groups, found food there and were tolerated. They were slowly domesticated and perhaps saw humans as an Ersatz pack. Wolves are highly territorial animals. A lone wolf could have alerted the humans when intruders, man or beast emerged near the settlement, drawn in by the lure of vengeance and livestock. A lone wolf could be fed with the remains and would pay off its costs very quickly.

    Once humans began to tame them and breed them, they found a companion that was highly useful for the battue. They could smell and rouse prey in much more effective ways than humans could —a successful cooperation of similar hunters. Such wolf-dogs easily paid for their meal, too. As highly social animals they accept their lot in a hierarchy which was a prerequisite to keep them around.

    When humans began to herd animals, yet another trait could be utilized. Wolves goad their prey to exhaustion, a trait that could bred into goading of larger herds, which perhaps even only allowed humans to manage larger herds of domestic animals.

    This, too, was possible by referring to and emphasising the traits wolves already had within their natural niche, hunting behaviour and social skills. Later, a function of the canine companion was to watch the yard, again by exploiting their ancient trait of territorial behaviour. As they were now around and in the house all the time, they were slowly bred into the niche of the pet, lapdog and friend. The diverse breeds of dogs could then be interbred and many more variations were possible.

    I have to keep the cats on a shorter leash. The family of the cats are almost always solitary hunters. One notable exception are lion prides, but which are organized around kin groups of females (all are related) and are thus stable over generations. They are formidable hunters, whereas the males are not. Male lions roam about in small groups or as buddies, but are poor hunters. I am not aware that any human culture ever made use of their abilities, which might have to do that their social behaviours as well as their hunting skills do not align at all with human interest, and there was no reason to breed them. There is no lone wolf counterpart among the cats – a highly social yet momentarily solitary animal.

    In summary, dogs have evolved into more diverse forms because they evolved alongside human culture and could be bred into the newly created “cultural niches”, that referred back to traits their wolf ancestors already had, such as social pack behavioirs, accepting their place in a hierarchy, lone wolves that would find another pack and integrate (cooperate with non-kin groups), their endurance hunting behaviours that was useful for hunting but also for keeping herds. And territorial behaviors that made them formidable alarm systems first, and later allowed them to occupy yet another “cultural niche” on the farms and settlements, and yet once around the house, as pets.

    By contrast, cats were only useful once humans had settlements and corn (which attracted rat and mice). Here they found a “cultural niche” as vermin killers. It played well to their traits, as they would pay for themselves and keep the pest in check with little further human interaction. Once around the house, like dogs, the cats could occupy “cultural niches” such as pets. But since the bigger cats were never really useful, socially incompatible, with different hunting patterns, they were never bred into such “cultural niches”.

  91. Continuing where I left off at #80, allow me to (tandem) repeat: While it would be foolish to dismiss the human contribution to the multiple breeds of dog today, I humbly submit that their plasticity is inherent and due to mechanics within the dog’s genome:

    http://blog.greencupboards.com/2011/01/19/who-designed-your-dog/ –
    “Tandem repeats, which are sections of the DNA sequence that repeat themselves over and over again, are responsible for the broad scope of modern day dog.”

    http://eweb.furman.edu/~jfoltz/Courses/BIO102/lect/Wolf2woof/Dogs_Evol.pdf –
    “Canids are inherently more genetically plastic than other Carnivore and other mammals…. The genetic basis is Tandem Repeats (TRs)in nucleotide bases.”

    http://www.karelianbeardog.us/kbd_science.html –
    “Dogs are believed to have more physical and behavioral variations that any mammal on this planet…. A group of scientists at UT Southwestern… noticed something fascinating: specific regions in the dog’s long strings of DNA code that are prone to mutation, called tandem repeat sequences. These tandem repeats are like a single word repeating many times within a sentence, for example, A-C-A-C-A-C-A-C-A-C. They have identified what they believe to be a genetic mutation mechanism that is responsible for the dog’s rapid evolutionary changes.”

    1. This is fascinating, good post! But the high variability in repeat length (and the ‘purity’ of the repeats) doesn’t appear in the wild cousins of dogs (wolves, coyotes, foxes). So it seems the high variability in repeat length is, itself, a product of artificial selection.

      In other words, the enhanced plasticity of the domestic dog appears to have been, itself, selected for by breeders.

      Interestingly, there appears to be a natural selection correlate; natural selection too, appears to have selected for increased mutability at times. In the link below, it has selected for increased infidelity of a DNA replicase

      http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1001943

      1. This article by Laidlaw et al 2007 (J Hered 98:452) (http://www.ncbi.nlm.nih.gov/pubmed/17437958) seems to indicate that the high slippage mutation rate associated with increased tandem repeat frequency does occur among other Canidae, but not in other Carnivora (but also occurs in rodents – known for frequent chromosomal rearrangements). So it seems unlikely that the high tandem repeat/slippage mutation frequency resulted from selective breeding, but was probably already present in the population prior to domestication (which would, of course, have allowed for greater diversity of domestication-associated traits, as well as other morphological variants).
        Dogs also appear to have a higher frequency of retrotransposons.
        Here is a nice review from 2010, just fyi: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3322674/

  92. And. . . . the comments are now over. At least any post after this one does not count in the contest.

    Thanks, all! It may take a while to adjudicate given my travels.

  93. Not to be too pushy, but I posed this question to my Evolution course (whom had some interesting hypotheses), and we are waiting to hear your brilliant insights!

    1. This is just an idea, and I’m sure others had it. Dogs came pre-socialized, so they were willing and able to take human direction as a putative pack leader. Cats came unsocialized, as they all descend from a solitary European wildcat (dogs descend from the social gray wolf) and so you couldn’t get cats to DO STUFF without first selecting them for sociality. Why would anyone do that when dogs already had the sociality? If you look at the morphological variation among wild felid species, it is at least as divrse as that of wild dogs, so I don’t think cats lack genetic variation, ergo you could make cat breeds as diverse as dog breeds. But since most dog breeds originated as working breeds, you’d have to take that extra step in selecting for cat socialization before you could create working breeds of cats. Nobody wanted to do that, and I suspect it would be hard. Why bother if you can get dogs to do stuff already?

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