Types of keelbacks

Rhabdophis is a genus of snakes in the family Colubridae, the largest snake family and the one that contains most of the world's so-called typical snakes. Members are commonly called keelbacks because of the raised ridge, or keel, running down the center of each dorsal scale, which gives the body a rough, matte texture rather than a smooth shine. Our database lists 30+ species, including Heller's Red-necked Keelback, the Tiger Keelback, the Chinese Tiger Keelback, and the Siamese Red-necked Keelback. The repeated use of red necks and tiger-like banding in those names points to the bold collar and crossbar patterns common in the group.

These are snakes of eastern and southeastern Asia, ranging across regions such as Japan, Korea, China, and into Southeast Asia. They are strongly tied to water and damp ground, turning up around rice paddies, marshes, pond edges, ditches, streams, and wet meadows. This is a semi-aquatic, terrestrial group rather than a tree-dwelling one. Most are slender to moderately built, medium-sized snakes with round pupils and the keeled scales described above. Many species show a distinctive band of red, orange, or yellow on the neck just behind the head, which is one of the most reliable field cues for the group, though color and pattern vary widely between species.

Honest safety framing matters here, because keelbacks break the usual rule that colubrids are harmless. Several Rhabdophis species, the Tiger Keelback most famously, are rear-fanged and genuinely dangerous. They have enlarged grooved teeth at the back of the upper jaw and a Duvernoy's gland that produces a venom affecting blood clotting. Serious bites can cause internal bleeding and have caused human deaths. On top of that, many species sequester defensive toxins from the toads they eat and store them in specialized nuchal glands in the neck, so that a predator biting the neck gets a dose of toad poison. Because of this, no Rhabdophis should be treated as a safe snake to pick up. Do not handle a wild keelback, and if a bite occurs seek emergency medical care immediately.

Ecologically, keelbacks are active hunters of cold, wet-skinned prey. Amphibians are the core of the diet, especially frogs and toads, which is exactly why some species can recycle toad toxins for their own defense. Fish and tadpoles are also taken, and the diet can shift with age and season as different prey become available. They are mostly diurnal to crepuscular, foraging by day and in the cooler hours near water.

Reproduction in the genus is egg-laying. Females deposit clutches of eggs in moist, sheltered spots such as leaf litter, soil, or rotting vegetation, and the young hatch already equipped with the genus's neck defenses, sometimes even drawing on toxins passed from the mother. When threatened, a keelback may flatten and raise its neck to flash the bright collar and present its toxic nuchal region toward an attacker rather than fleeing, a warning display that doubles as a delivery system for the stored poison.