A Little More About Reptiles: According to Dr. Christoph Mans, a zoological veterinarian / exotic animal specialist at the University of Wisconsin - Madison Veterinary Care Hospital. There are more than 3,400 species of snakes worldwide, and they exist on every continent except Antarctica. Some snakes, like the corn snake, are friendly and can make excellent pets for people who like to keep snakes. The corn snake can get up to 6 feet in length and is native to the southeast and central United States. In New York, the most commonly seen snake is the garter snake. Posing no harm to humans, garter snakes eat only fish and amphibians. However, that species is too "dangerous" according to the DEC to be privately possessed.