Types of cat snakes

Boiga is a genus of rear-fanged snakes in the family Colubridae, the largest and most diverse snake family. The common name cat snake comes from the vertical, slit-shaped pupil that contracts in bright light much like a cat's eye, a hallmark of nocturnal predators. With 30+ species in our database, Boiga is a large and well-studied group spread across the Old World tropics, and it is one of the better-known examples of mildly venomous, rear-fanged colubrids.

The genus ranges widely across South Asia, Southeast Asia, southern China, the Indonesian and Philippine archipelagos, Australia, and parts of sub-Saharan Africa. Most cat snakes are arboreal, living in trees, shrubs, and vine tangles, and many are equally at home in forest, mangrove, plantation, and garden settings. Their climbing lifestyle and tolerance for disturbed habitat means they are often found near human dwellings, including inside roofs, sheds, and outbuildings where geckos and birds are easy to find.

Cat snakes are recognizable as a group by a combination of traits: a large, distinct head that is clearly wider than the slim neck, large eyes with vertical pupils, and a long, strongly compressed body well suited to moving through branches. Coloration varies widely between species, from plain browns and grays to bold bands, blotches, and rings in yellows, oranges, and blacks. Many species are slender and ribbon-like in build. The Brown Tree Snake is the most infamous member, notorious as an invasive species that devastated native bird populations on Guam after being accidentally introduced.

On venom and safety, cat snakes are rear-fanged and mildly venomous. They carry enlarged, grooved teeth at the back of the upper jaw and a Duvernoy's gland that produces a venom used to subdue small prey. For most healthy adults a bite typically causes only local effects such as swelling, redness, and pain, and serious envenomation of humans is uncommon because the fangs sit far back and venom delivery to people is inefficient. Even so, mildly venomous is not the same as harmless, reactions can vary between individuals, and a bite from a rear-fanged snake can be more significant than expected. Never assume a wild snake is safe to pick up, do not handle a snake you cannot positively identify, and if anyone is bitten, treat it as a medical emergency and call US Poison Control at 1-800-222-1222 or your local emergency services.

Ecologically, cat snakes are mostly nocturnal, arboreal hunters. Their diet centers on lizards, especially geckos, along with birds and their eggs, bats, frogs, and small mammals, and the rear fangs and mild venom help them control active prey in the trees. Like the great majority of colubrids, Boiga species are egg-layers that produce clutches of several eggs. They tend to be alert and can be defensive if cornered, raising the forebody, gaping, and striking, but they rely first on climbing, hiding, and fleeing rather than confrontation.