A colubrid (from Latin coluber, snake) is a snake that is a member of the Colubridae family. It is a broad classification of snakes that includes well over half of all snake species on earth. Colubrid species are found on every continent, except Antarctica.
A colubrid's body is almost completely covered in scales. They have highly flexible jaws, allowing them to consume large prey items, and have no remnant of a pelvic girdle.
While most colubrids are non-venomous (or have venom that isn't known to be harmful to humans) and are normally harmless, a few groups, such as genus Boiga, can produce medically significant bites, while the boomslang and the twig snakes have caused human fatalities. The venom is a modified form of saliva, secreted by glands in the upper jaw.
The venom-injecting fangs associated with venomous colubrids are almost always in the back of the mouth, unlike those of vipers and elapids. Even non-venomous colubrids often have fangs in this position, and use them to puncture egg-shells or similar food.
The Colubrids are certainly not a natural group, as many are more closely related to other groups, such as elapids, than to each other. This family has classically been a dumping ground for snakes that don't fit anywhere else. There is on-going mitochondrial DNA research which may sort out the familial relations within this group.
Subfamily Colubrinae - nearly 100 genera
Subfamily Homalopsinae - about 10 genera
Subfamily Natricinae - about 30 genera
Subfamily Pareatinae - 3 genera
Subfamily Pseudoxyrhophiinae - about 20 genera
Subfamily Xenodontinae - some 55-60 genera