Tetrachromacy is demonstrated among several species of bird, fish, amphibian, reptile, insect and some mammals. Monitor lizards have become a staple in the reptile pet trade. Rat snakes are commonly kept as pets by reptile enthusiasts. There are also several introduced species of reptile and amphibian. One state reptile, the bog turtle, is Critically endangered. Sea turtles are the first biofluorescent reptile found in the wild. Remains of pig, deer, rodent, reptile, monkey, crab and fish were found. One species, the atoll fruit dove, is specialised in taking insect and reptile prey. This allowed the evolution of a number of flightless birds and large reptile species. Nevada is the only state to possess a skeleton of this extinct marine reptile. A parallel convergence occurred with the now extinct marine reptile ichthyosaur. The tuatara is a notable reptile endemic to New Zealand. Many cultures have legends of creatures which are part human and part reptile. Chameleons have the most distinctive eyes of any reptile. Supercooling is also a common feature in some insect, reptile, and other ectotherm species.