any member of the most common family of snakes, Colubridae, characterized by the complete absence of hind limbs, the absence or considerable reduction of the left lung, and the lack of teeth on the premaxilla and usually having a loose facial structure, relatively few head scales, and ventral scales as wide as the body. There are more than 1,600 species of colubrids, and they account for about two-thirds of the world's snakes. Most have solid and conical teeth; some have grooved teeth at the rear of the upper jaw and produce a venom that induces paralysis. A few have short, erect fangs in the front half of the mouth. For most of the venomous colubrid species, a bite unaccompanied by chewing is rarely harmful to humans. In a few species with fangs, a single bite can be dangerous and possibly fatal.

Colubrids lay eggs, but some (especially the aquatic forms) are live-bearing. Colubrids occur in virtually all habitats.