Some animals seem to be the same color all over. But the basic format is light bellies, from fish to fowl to fawns. I’m sure some animals have lighter topsides. What are they.
I’m not sure there are any, other than peroxide blonds. I can think of advantages to having a dark top but light bottom, but I can’t think of any advantages for the other way around.
I think some fish and other marine animals are – those whose predators come from above them.
Hmm. I think I’d need an example. Predation from above is precisely why fish tend to be dark on top; if they were light on top they’d be easier to spot from above.
Exactly. The whole point of the light belly, dark back paint scheme is that when you look down on the creature it blends in with the darkness below, when you look up it blends in with the lightness above, and when you look from the side the shadows on the lighter belly and the light on the dark back average out to close to the same shade.
Does this count? It’s a pattern of Paint Horse called splash overo.
http://image04.webshots.com/4/6/38/1/53563801lzZIOT_ph.jpg
http://hiddencreekestate.com/horses/images/horses/phantom1t.jpg
First, that’s the norm; the opposite of what the OP is asking for.
Second, I don’t think domesticated colorization counts. There are goldfish and koi, for example, that have been bred to have light, or even white, dorsal surfaces.
Yup – brain fart on my part. I withdraw my comment.
Well, now that you mention it, I suppose I meet the OP’s criteria. Blonde hair on the top of my head, light brown beard, and dark brown hair everywhere else. No peroxide involved.
I couldn’t think of any, but apparently there are a few black-bellied birds.
In the last example, the dark-on-the-bottom scheme is “breeding plumage”, leading me to guess that this pattern is more sexy than practical.
How about the Sifaka lemur?
Skunk
Honey badger
European badger
All carnivores. Huh.
Not uniformly so, but some giant pandas have dark bellies and white backs.
Interesting question. After a little googling, there seem to be examples of salamanders, sheep, hamsters and birds with darker/black bellies but none of those would be considered the norm.
The pattern is known as countershading, and is extremely common in animals that want to avoid detection.
Another bird that is black below and pale above is the breeding male Bobolink.
These other types of color pattern are found in species that are not cryptically colored. Such conspicuous color patterns may be for breeding purposes, social signalling, or warning coloration to show a predator that the species is dangerous.
For an example of the latter, see the hog-nosed skunk. The honey badger, or ratel, may be another example.
Oh, sure. My dog when he comes in from the rain.
Btw, the wikipedia article on countershading gives the example of a caterpillar. It is darker on the bottom, but I do not think it is poisonous and it obviously isn’t trying to attract mates. I’m having a bit of trouble imagining how it is camouflage, but perhaps the bottom part is meant to have the color of a twig.
Without a caption it’s hard to say what that illustration is trying to depict. However, I would guess it shows a caterpillar that habitually feeds in an upside down position, and so is darker on the underside. The upper illustration shows it in normal feeding position, when its “reverse countershading” works. The lower illustration shows it in upright position, when it doesn’t.
Well, there are more than I would have thought.
I’ve often heard how “clever” animals are to be darker on top, and I think that’s guff. They are just carrying on the pattern of fish, who live in an entirely different world. The better way to put it is that belly color seldom matters, has no impact on survival rates. The tops of animals are obviously important, as the ermine in snow converts to stoat in the summer.
I’m not so sure I’d dismiss a function right off the bat. Belly fur can be substantially different from the upper coat in terms of length, thickness and texture as well as in coloration. At least some of those differences have to result from selection pressures.
I can imagine that light-colored fur would have slightly different thermal properties than dark-colored fur. Perhaps a light belly is useful in environments where the ground gets hot the during day and one would like to reflect infra-red. (The back fur, being driven more by camouflage needs might have to stay darker regardless of temperature).
That’s just a WAG, but I sure wouldn’t chalk it up to fish ancestores without more analysis.
While many terrestrial mammals are rarely seen from below, they very frequently are seen from the side, and countershading is important from that viewpoint too. Belly color certainly matters, since this color pattern is so prevalent in a variety of unrelated taxa, from insects to vertebrates. “Just carrying on the color pattern of fish” won’t work for mammals, since ancestral mammals were almost certainly nocturnal and probably not countershaded.