Heterodon is a genus of harmless colubrid snakes endemic to North America. They are stout with upturned snouts and are perhaps best known for their characteristic threat displays. Three species are currently recognized. Members of the genus are commonly known as hognose snakes, hog-nosed snakes, North American hog-nosed snakes, and colloquially puff adders.
Heterodon
Western hog-nosed snake (H. nasicus)
Colubridae is a family of snakes. With 249 genera, it is the largest snake family. The earliest fossil species of the family date back to the Late Eocene epoch, with earlier origins suspected. Colubrid snakes are found on every continent except Antarctica.
Colubridae
Two Indian rat snakes (grey and yellow)
A natricine, Thamnophis sirtalis
A dipsadine, Sibon longifrenis