The natural folds and wrinkles of a hand imitate elephant skin.
Italian artist Guido Daniele began as a hyper-realistic illustrator. He has painted backdrops, trompe l'oeil art, and done body painting on both bodies as well as his series of animal hand painting, which he calls "Handimals." He's used some of these animals in an advertising campaign for the World Wildlife Fund.
This one seems to switch back and forth
from a hand and arm to a swan's head.
This parrot has a ferocious beak.
Notice the dark thumbnail.
At first, I couldn't see the hand at all.
This one is more hand than dolphin unless you squint.
Then it's a oddly angry dolphin.
An alligator who has just swallowed something.
This eagle obviously looks like a pair of hands in the back,
but I can't see evidence of hands or fingers in the eagle's body.
Here's another angry animal that morphs from eagle to hand.
This illustrates the universal hand gesture for "bird."
The human arms are black.
A curious giraffe.
A great use of perspective fools your eye.
An iguana with a lot of character.
This one might make a deceptive shadow on a wall, as well.