Given the importance we affix to looking someone (or something) else in the eyes, itâ€™s no wonder that heterochromic creatures, or creatures with two different eye colors, are so striking. Though heterochromia is fairly rare in humans, its occurrence is far higher among animals, especially cats. Take a look! Heterochromia is a genetic trait that, depending on the creature it happens in, can be due to inbreeding, genetic inheritance or mutation. In some breeds of cats, like the Turkish Angora, heterochromia is a desirable trait that breeders try to maintain. One cat in this list â€“ Venus â€“ is heterochromic due to chimerism, a different genetic trait that causes her body to express different pigmentation genes for each half of her body.