by Greg Mayer
I promised baby tapirs, so here are baby tapirs! (From Zooborns.)
Adult Malay tapirs, as you’ll recall, are particolored:
The three other species of tapir, all from the Americas, also have spotted/striped young. Here’s a lowland tapir, found throughout much of cis-Andean tropical South America; the others are very similar in appearance.
We can thus see that all baby tapirs look much alike, and quite different from adults. Adults are either self-colored (the American species) or particolored (the Malay tapir). (It’s interesting that both young and adults have white edges to their ears.) The question is, is this coloration of the juveniles an adaptation? Or is it an ancestral feature of no current utility, which makes a brief appearance in the young, but is then lost (like the coat of hair that human babies have in utero)?
17 thoughts on “How the tapir got his spots II”
Well obviously it’s a whim of the “designer,” just like P. falciparum is. That’s why we know ID is based on religion, ultimately the Bible, because its “designer” is arbitrary and cruel.
Anyway, the baby’s cute, sort of like a piglet, only cuter thanks to spots and stripes.
Here’s a thought. If the baby’s colouring has no camouflage utility, might it serve as a signal to adult tapirs saying “I’m a baby, please look after me?” Perhaps one could test this by putting a jacket around a baby to see what effect this has on parenting.
I’m no biologist: so shoot me down.
I’m not a biologist either; but the baby’s coloring is obviously camouflage: it also looks remarkably close to a fawn’s ‘dapples’ both of which mimic the pattern of light on a forest floor during the day.
Of course that’s not to say that that would in any way prevent the same patterns from making an adult of the species go: “Dawwwwww, how cuuuute!!”
The adult, on the other hand, I dunno about … my first thought was actually: that looks sorta like a Panda’s black and white coloring (which doesn’t, as near as I can tell, do squat to blend in with the bamboo forests pandas call home) and one can never forget the Peacock’s Tail which is more or less exactly ANTI-camouflage: biology is very messy and accidents can and do happen all the time … it’s just that they also tend to mostly die out so quickly (relatively speaking) that we never see them.
I wonder if ear movements have some social signaling function in tapirs? That might explain the white edges.
Aren’t piglets of wild boars also striped? Or am I just making that up because I was wandering how these piglets taste … ?
A number of years ago an openair opera concert in Copenhagen next to the zoo scared a tapir to death. Supposedly the vet students at the nearby veterinary college ate it after having performed the necropsy.
I remember that. It was an opera sound test caused by the unfamiliar sounds, actually, and the tapir died from stress. At least, that’s what the news said at the time.
Never heard that someone ate it. I really wonder what it tastes like.
Are the babies left alone for extended periods in the wild? That could lean it towards camouflage.
I’m a bit confused about why it’s more reasonable to start with the assumption that these are atavistic and not adaptive?
As I interpret it, this debate can be summed up as whether or not a statement like
(1) “This coat pattern was once adaptive, now it isn’t, and it persists in nearly 100% the population”
is really a more reasonable assertion than
(2) “It is currently (or was at least VERY recently) advantageous.”
Assuming that’s a fair interpretation, then if it were currently neutral, would we expect to see it conserved across Tapir species (i.e. it is neutral in all populations)? I suppose this could maybe happen if it (very) recently lost it’s fitness benefits, in which case it’s questionable whether not this counts as “currently” advantageous.
What about similar patterns (as mentioned previously) in other vertebrates (not just in Artiodactyla): many species of birds, cats, canines, fish, etc. have natal coloration and patterns similar to the Tapir’s stripes and spots, as do some adults. Have we really not yet studied whether or not similar cryptic patterns and coloration in all of these other species confer survival benefits for the young?
If we really know nothing from previous studies of other taxa, then what can we learn from existing wild populations that have variation in coat color and pattern, like feral pigs, cats, chickens, etc? It seems predation experiments in any of these species could help resolve the issue?
If it’s simply a question of whether or not we can take what we know about other species and infer that coat pattern and color in young Tapirs provides a survival advantage, then (short of doing controlled experiments on a group of threatened/endangered animals…) we should at least be able to check for conditions that would support or refute making such an assertion, and base our claims on those grounds.
So are there really no potential threats to young wild tapirs? Surely things like big cats, wild canines, people, etc. could potentially prey upon a baby Tapir, and would rely on sight to capture it? Are there hits of parental care benefits that come from the coloration (as Leigh mentioned)? Tapirs do seem to have poor vision, so I’m doubtful this is a big part of what shapes coat color, though it’s perhaps more consistent with color and pattern being unimportant to parental care?
Anyway, feel free to clarify and/or correct me if I’m missing something. I just don’t see why we should be so certain of calling this an atavistic trait and not a currently advantageous one.
I’m with ObSciGuy. The ubiquity of striping, spots, and dappled patterns in juveniles in many unrelated animals suggests adaptation to me. Why assume vestigiality?
If the stripe/spots aren’t camouflage, and if tapir close-range vision is poor, maybe they help mama see her offspring and not roll over on them?
What would prevent feral grandmas from leaping out of the brush and pinching its widdle cheeks?
Adorable! If it were green I’d suggest that it evolved to be camouflaged in watermelon patches.
I agree that the spots are most likely “sun dappling” camouflage.
Tapir calves have the pattern as camouflage. When their mothers are foraging, the babies can hide in undergrowth very well. Like baby peccaries, various deer species and a heap of other animals.
Adult Malaysian Tapirs have the white saddle supposedly for camouflage – it breaks their outline in the jungle, making them harder to spot. Having said this, there is a mutation (or perhaps a sub-species – it’s unknown at this point) that means that some adult Malaysian Tapirs are all black and have no white saddle.
Either way, the white saddle most likely started as a mutation. Malaysian Tapirs are estimated to have diverged from the three tapir species of the Americas around 20 million years ago, but for whatever reason, none have lost the white ear tips.
There are rumours of a dwarf Brazilian Tapir subspecies (or entire species, according to some) that allegedly don’t have the white tips. However, if there is a separate (sub)species, it is almost completely unknown at this point in time – more research is needed to confirm or disprove the theory.
I have kept a variety of chickens that are not your average egg/supermarket breeds, and all the chicks have very camouflaged coloring/striping patterns. This seems pretty ubiquitous in animal young and if not originally selected for is probably a nice coincidence that certainly would not be selected against. I assume the animal loses it as it ages because an adult is much more able to look after itself and not need it as much. Or perhaps all ancestral chickens were striped like chipmunks. http://www.heirloomheritagefarms.com/buttercup.html
Don’t young deer have similar patterns?
/me is thinking about Bambie’s spot’s of course.
Anybody who’s ever been in the jungle would know that the spots are for camouflage. It mimics the spots of light that shine down through the leaves. Baby tapirs are very hard to spot in the jungle. I had a pet baby tapir for a while. He loved to swim and could hold his breath for a very long time under water.