Snakes of North America
CLASS REPTILA
ORDER SQUAMATA
SUBORDER SERPENTES
FAMILY LEPTOTYPHLOPIDAE (slender blind snakes)
This family of snakes is composed of 50 species in two families. They are generally regarded as the most primitive snakes, having a pelvic girdle and vestiglial hind limbs. They have a single lung and oviduct and are well adapted to their burrowing life style. They feed exclusively on small invertebrates such as ant and termite larvae. Leptotyphlopids are oviparous. There are two species of this family in North America.
FAMILY BOIDAE (boas and pythons)
Boidae is a large family of snakes that includes all five of the world's giant snakes. Boids are an ancient family that are characterized by a mixture of modern and primitive traits. They have flexible jaws found in more advanced families but also retain a pelvic girdle, vestigial hind limbs, and many use both lungs. While there are close to one hundred species of boids worldwide, there are only two species of boas found in North America, both in the sub-family Eryciniae.
COLUBRIDAE (colubrid snakes)
The Colubrid snakes are sometimes refered to as "typical snakes". They comprise the largest family by far with over 2000 species worldwide. Most are medium sized snakes, and all lack a pelvic girdle and have no vestigial hind limbs and whose left lung is either absent or greatly reduced. Most species are considered members of two large subfamilies, Colubrinae and Natricinae which are distinguished by the presence (Natricinae) or absence (Colubrinae) of spines on the lumbar vertebrae. Both subfamilies contain over 200 genera. The Colubrinae subfamily includes two of the genera popular with herpetoculturists, Elaphe and Lampropeltis. The Natricinae subfamily includes water snakes (Nerodia) and garter snakes (Thamnophis) among others. With a family this large, there will always be disagreements about classification, especially regarding the numbers and types of subspecies. This list includes 102 species of Colubrid snakes found in North America. Subspecies are not included in this scheme. Other lists may vary.
