Diamondback Water Snake – Nerodia rhombifer

Trigg County KY


The Diamondback Water Snake is Kentucky’s largest species of water snake and is impressive both in size and disposition. Adults often attain 48” in length and are known to reach a maximum of 63” in total length. As with other species of water snakes the females are generally much larger than the males and are of greater girth proportionally. Also, as with other species of Nerodia, the Diamondback Water Snake is quick to defend itself. It has been suggested that the perils of an aquatic environment are often greater than those in more terrestrial settings. This may have resulted in water snakes evolving a more rapid expression of self defense than is the norm for most other genera of snakes. This species is also capable of excreting copious amounts of musk from its vent as a further deterrent.

Aside from size, males can be recognized by a number of protuberances beneath the chin and this is the only water snake native to Kentucky with this feature. Gravid females give birth to large litters of live young in late summer. The young are similar to the adults in coloration but are typically of higher contrast. Primarily nocturnal, the Diamondback Water Snake is usually seen basking on summer days and foraging after dark. Early and late in the year when the nights are still cool this snake will often reverse this trend and become more active during the daylight hours.


Perhaps our most aquatic species of water snake, the Diamondback is seldom found more than a few feet from water and is often encountered within the water itself while prowling for food. Prey consists of fish, frogs and aquatic salamanders with studies suggesting fish as the primary diet of adults. Most fish that are consumed are considered rough species (non-game) by most with bullhead catfish figuring prominently in some locations. The Diamondback has little trouble feeding on bullheads despite their sharp dorsal and pectoral spines. This snake is also apt to scavenge upon dead or dying fish as well as other carrion.


Marshall County KY


In Kentucky, the Diamondback Water Snake is found throughout the Jackson Purchase Region through portions of the Western Coal Field. We have observed this species in a number of locations including Fulton, Hickman, Ballard, Marshall, Trigg and Hopkins counties. In these area’s it prefers permanent water sources and is usually associated with oxbows, river swamps and other quiet water situations.

Phil Peak





Fulton County KY