Types of keelbacks

Helicops is a genus of aquatic snakes traditionally placed in the family Colubridae, the largest and most varied family of snakes. Colubridae is a sprawling group that includes the majority of the world's harmless and mildly venomous species, and within it Helicops sits among the New World watersnakes. As classification has been refined, many researchers now place Helicops in the subfamily Dipsadinae (the Neotropical dipsadines), but for general purposes it remains a colubrid-type snake rather than a member of the front-fanged venomous families like vipers or elapids.

These snakes are native to South America, ranging widely across tropical and subtropical regions including the Amazon and Orinoco basins and reaching into parts of the Atlantic forest and surrounding wetlands. They are tied closely to water and live in rivers, streams, lakes, marshes, flooded forests, and slow backwaters. Many species spend most of their lives in or near the water and are rarely found far from it.

In general terms, members of Helicops are recognizable as stout, water-adapted snakes with eyes and nostrils set high on the head, which lets them watch and breathe while staying mostly submerged. Keeled scales give many of them a rough texture, and patterns often run to bands, blotches, stripes, or spotting in browns, olives, and darker tones that blend with muddy water and riverbeds. Several common names reflect this look, such as the various keelbacks and the brown-banded watersnake. Telling individual species apart usually requires close attention to scale counts and locality rather than color alone.

Helicops are rear-fanged snakes, meaning any venom-conducting teeth sit toward the back of the upper jaw rather than at the front. They are not considered dangerous to people in the way vipers or coral snakes are, and bites typically cause only minor local effects. Even so, no wild snake should be handled. Rear-fanged species can deliver saliva and venom with a sustained or chewing bite, individual reactions vary, and identification mistakes in the field are easy to make. Treat any wild snake as best left alone, and if a bite occurs or a snake's identity is uncertain, seek medical evaluation rather than self-treating. In the United States contact Poison Control at 1-800-222-1222, and elsewhere contact local emergency services.

Ecologically, Helicops are predators of the water column. Their diet is dominated by fish and amphibians, including frogs and tadpoles, which they pursue and seize in the water. Activity is often nocturnal or crepuscular, and the snakes are agile swimmers that can stay hidden along banks and bottoms. Reproduction varies across the genus: some species lay eggs while others give live birth, a flexibility seen in a number of aquatic snake lineages. They are generally non-aggressive and rely on concealment and a quick retreat to water when threatened.