Ectrodactyly is not only a genetic characteristic in humans, but can also occur in frogs and toads,[22] mice,[23] salamanders,[24] cows,[4] chickens,[9] rabbits,[9] marmosets,[9] cats and dogs,[25] and even West Indian manatees.[9] The following examples are studies showing the natural occurrence of ectrodactyly in animals, without the disease being reproduced and tested in a laboratory. In all three examples we see how rare the actual occurrence of ectrodactyly is.