Taken from the Wikipedia article on boas. Spot the wind up:-

"Though still exported from their native region in South America in significant numbers, boa constrictors are widely bred in captivity, both for the casual pet trade and among serious herpetocultural hobbyists. In addition to normal-appearing specimens, animals exhibiting a wide variety of weird traits, such as neon colors,pattern mutations (e.g. albinism), and even snakes with legs are being produced. Many of these are quite expensive."