by Matthew Cobb
It’s Thursday, and we all need cheering up. In the UK, several hundred thousand 17 and 18 year olds will get the results of their A and AS level exams, which will have a decisive influence on their future. So here for them, and for the rest of us who don’t have to get their results (although some of us have children in that age bracket to worry about), is a hamster eating a piece of baby corn:
This being a somewhat educational blog, we can’t just go ‘aww, so cute’. So here are today’s questions. Write on one side of the paper only:
– Is it strictly speaking ‘eating’? What’s a good definition of ‘eating’?
– The advantage of having a shopping basket in your mouth is fairly obvious. Why haven’t other animals evolved this adaptation? Or have they?
– If you look at a hamster skeleton, can you tell that the living animal has a pouch? Might stegosaurs have had pouches to stuff all those ferns in?
Here’s a picture of a hamster skull ((c) skullsunlimited.com). If this were a fossil, would we reconstruct the hamster with pouches?
To get some idea of how big those pouches are, here’s a reconstruction from the National Museum of Ireland, which seems to have attached condoms to a hamster skeleton:
And to remind you what it’s all about, this video shows a blue hamster snuffling up rice:
Weird! That hamster appears to have three ears.
Very wrinkled outer ears, I suspect.
Matthew, you are now officially MC Hamster!
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🙂
Matthew,
You have most definitively “jumped the shark” with this post. Just sayin’.
How so? Sharks are in the eye of the beholder, but the questions are genuine, especially the one about knowing from a fossil whether there were pouches.
What do you mean by “jumped the shark.” I sincerely hope that’s not a criticism.
Comes from a Happy Days episode, although I don’t see why it’s applicable here
http://en.wikipedia.org/wiki/Jumping_the_shark
Greedy. Om gnome gnome gnome!
And I didn’t know about “blue” hamsters. Thank you!
1. The movie shows that some processing is necessary in cases. In analogy with cows, I would say this is “eating”. Eating := internal food processing.
2. Pelicans.
3. Theoretically, could one observe increased load structures and wear & tear on the neck & skull region?
There are also 23 years olds getting my A-Level results today.
That hamster was quite impressive. I had no idea their pouches (is that their technical name?)were so large.
“This being a somewhat educational blog”
Blog? This is a blog? Does Jerry know?
Many birds store food temporarily in either their crop or in a gular pouch.
The good news is that the university uptake for Physics & Chemistry have gone up by circa 20%. Another nail in the coffin for ancient superstition courtesy of education.
I feel I’ve been left in suspense with the corn eating hamster – how did the hamster eat it afterwards? Birds have their crop but that’s not really the same thing. If birds have a crop, maybe the steggy could.
I don’t think steggy would have a crop – that guy’s like a cow. Maybe other dinos though….
The pouch is a modified cheek; there’s an argument as to whether any dinosaurs had a cheek proprement dit. Probably not. So poor old steggy had to just swallow all that stuff down. Hundreds of kilos of it per day, just to keep alive. And then they went extinct.
Poor thing. But he had that cool cow like stomach! He had a caecum maybe?
Gastroliths are also possible, though as far as I know they’ve only been found in association with sauropod fossils.
Hundreds of kilos? Probably not that high. If I recall correctly, large dinosaurs currently aren’t thought to have had quite the same metabolic rates as equivalent sized mammals.
I see a good selective advantage for a small mammal dodging predators to be able to grab food in passing and keep moving to consume it in relative safety later. However if you are a 30 foot long herbivore such as a stegosaurus you can’t really hide in a small hole to quietly chew your stash. Like a herd of bison on a plain you are left with size, physique and behavior to deter predators. That does not of course preclude such an adaptation in whatever filled the hamster niche. My guess is that it would be tough, and controversial, to define these structures based upon fossilized skeletal remains. As noted above wear patterns might tell you something, but I bet you could get multiple possible explanations.
The crop in birds, I think, is more about breaking down seeds for digestion than about storage, as you note it’s not the same sort of structure. Mammals have a bunch of adaptations to allow them to consume large volumes of vegetation, ruminants take one approach, another is the cecotrophy, as practiced by rabbits. However those seem to be adaptations to eating tough plants such as grasses which didn’t evolve until a hundred million years after the stegs became extinct. Leaf eaters, such as monkeys have gone with intestinal adaptations and I think similar adaptations are also seen in vegetarian reptiles. However, I have no idea what the gut of a seed eating reptile, something that might be more similar to a hamster in terms of its niche, looks like.
Yes, no grass in those days, which was handy for the dinosaurs because I’m told they hated the thought of mowing their lawns and it was nice to have ground cover plants instead. 😉 There is some talk of hadrosaurs feeding babies “crop milk” but that’s probably unlikely.
“Crop milk” sounds about as appetizing as the semi-fermented fish that penguins barf into their infants. I suppose it’s all about perspective.
I nearly fell off my chair at the image of a steg riding a lawnmower – thanks 🙂
A stegosaurus on a lawnmower is cool, but still not as cool as Tyrannosauruses in F-14s.
Or this
The only way that could be more awesome would be if it had a bunny wielding hand grenades perched on the head of the T-Rex.
b&
One night my wife went out into the garage for something. Back in the house, I heard a startled exclamation, and then an urgent not-whisper, “Darrell get out here!”
So of course, out I go. Seeing that it is pitch dark in the garage I decide to turn on the light (duh!). My wife, looking like she is somewhere between fight or flight mode and laughter as she is intently studying the dark shadows in the garage, says “there’s something in here!!”
Sure enough as I start moving toward the area she is staring at something starts moving around, making a racket a 20 lb raccoon would be proud of. As I carefully search through all the “stuff” cluttering up the garage, fully expecting a sizable critter of some sort, I catch a glimpse out of the corner of my eye of a wee little furry sausage shape fleeing for new cover. We laughed our asses off.
Yeah, turned out to be a poor hungry little hamster. We made him comfortable in a cardboard box with some water then checked the fridge for some appropriate food. We just happened to have some already cleaned baby carrots, quite large by hamster standards, and so we offered him those. As soon as the carrots were out of my hand the hamster pounced on them like a Serval
and began to frantically jam them into his mouth. Not being familiar with hamsters I was worried and tried to gently slow him down, to no avail. He had several of these comparatively huge carrots bulging out on both sides of his face.
Well, after he was settled we started calling around the neighbors to see if anyone knew of anyone missing a hamster. Turned out the little guy had mysteriously disappeard from a house near by sometime the day before. Somehow this little guy survived for more than 24 hours, and moved across at least 100 yards of open terrain, in an environment alien to it that numerous snakes, coyotes, dogs, cats, hawks, owls and probably a few more animals that would enjoy eating a hamster, call home.
In the wild, hamsters move around a lot. Looking around on the internet, I find quotes saying they have a territory of about 3 miles each, and run 5-8 miles per night while foraging.
Wow! That is amazing for such a little rodent.
I presume that the huge circular gap between the incisors and the molars is indicative of a cheek pouch, it is there to allow access of baby corns to the pouch, otherwise it would make more sense to fill the gap in with teeth. So I suppose any other skeleton exhibiting a similar gap might be investigated for the possibility of cheek pouches.
You could be right, though the difference between a hamster and a rat (here: http://www.warrenphotographic.co.uk/20644-brown-rat-skull) is pretty minimal – the lower jaw ‘gap’ is marginally deeper in the hamster. Any rodentologists out there?
I’m not, but from what I’ve seen of different rodent skulls, that seems to be fairly common across the different rodent genuses.
As far as skull evidence for cheek pouches goes, I’m wondering if there’s specific structures in the skull that serve as anchor points.
I’m only going to use this side of the paper but, knowing that a few animals have food storage systems my curiosity needed some satisfaction so Wikipedia was engaged. Note that the testing guidelines didn’t specify a closed book.
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Cheek pouches are pockets on both sides of the head of some mammals between the jaw and the cheek. They can be found on mammals including the platypus, [edit: bats], some rodents, and most monkeys. The cheek pouches of chipmunks can reach the size of their body when full.
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The full body size of the chipmunk pouch and that most monkeys have pouches surprised me, and I had forgotten that the platypus has pouches.
– Oral pouching, maybe? I think I would prefer eating to at least encompass getting the food past the opening of the throat.
– Maybe some animals use their stomachs as pouch substitutes? I’ve seen dogs gulp their food then walk a few feet away and regurgitate. Having the stomach acids passing through the throat could be damaging, however, several animals regurgitate for their young. How do penguins store food for so long?
– doG doesn’t know but, it seems like it might be answerable.
After seeing that second video, I’m of half a mind to do a video art project of a live re-creation of Pac Man. Not sure what should play the role of the ghosts, though….
b&
“skullsunlimited.com” Exclamation mark, question mark.
Verily, Rule 34 must be true.
Returning to the question though … without a “face on” view, it’s hard to say, but the view presented does look rather as if there is more “depth” to the mandible than I see on most mammal jaw bones (few) which I’m familiar with. Trying to be more precise, there seems to be more variation in distance form the midline in the lingual-buccal direction. Most jaw bones I’ve looked at confine the bone to a fairly thin plank for maximal stiffness (in the plane of movement of the mandible) from minimal weight/ material.
Looking at the skulls site, I find a “face-on” view image at http://www.skullsunlimited.com/userfiles/image/category5_species_1601_large_3.jpg
… and it looks as if the mandible has a significant angle between the plane that directs the force of the teeth to their roots, while the posterior portion of the mandibles looks as if it is angled to resist forces in a different plane.
Does that provide a testable hypothesis?