Abnormally leucistic or near albino birds have been reported. The two kinds of white alligators are albino and leucistic. The true albino squirrels have pink eyes. The only known albino alligators are in captivity. Both albino and melanistic individuals have also been reported. The eyes of an albino snake are typically red or pink. Laboratory mice can have a variety of coat colours, including agouti, black and albino. Mammoth Cave is home to the endangered Kentucky cave shrimp, a sightless albino shrimp. Most are derived from the albino Wistar rat, which is still widely used. Nina Sky is an American female duo composed of identical twins Nicole and Natalie Albino. Many reptiles labeled as albino are, in fact, not completely lacking in all colour pigments. An albino anole has been reported and photographed. It is the result of the Burmese gene (cb), part of the albino series. Koprowski's attenuated vaccine was prepared by successive passages through the brains of Swiss albino mice. Chop Top has pale skin, like an albino.