Equipped with powerful venom, large fangs and a noisy rattle to dissuade potential predators, rattlesnakes seem well protected from most threats. However, some of the most dangerous predators of rattlesnakes are other snakes. Called ophiophages ("snake-eaters"), black racers, coachwhips, kingsnakes, milk snakes, indigo snakes and mussuranas are all capable of turning a deadly rattlesnake into a tasty meal.
Chasing Down Rattlesnakes
Despite their scientific name, black racers (Coluber constrictor) are not constrictors at all; instead, when attempting to subdue prey, they simply grab it and start eating—usually headfirst. As they only attain a lithe 5 feet in length, large rattlesnakes do not have to fear black racers. However, juvenile rattlesnakes are at great danger from the prowling predators, and black racers may devour several newborns at a time if they encounter a group that has not yet dispersed. Coachwhips (Masticophis spp.) are fast visual hunters that often prowl with their heads held high off the ground. Though their typical prey includes rodents, birds, lizards and eggs, coachwhips will eagerly consume rattlesnakes when they have the chance. It is not clear if coachwhips have immunity to rattlesnake venom or not—they use their great speed to avoid a rattlesnake’s strikes.
Why They're Kings
Common kingsnakes (Lampropeltis getula) are notorious ophiophages, and will consume rattlesnakes as readily as they will garter snakes. Immune to the venom of native pit vipers and capable of consuming a snake nearly as long as they are, kingsnakes also consume frogs, lizards, turtles, rodents and eggs. Some subspecies consume more rattlesnakes than others do: Florida kingsnakes (L. g. floridana) are primarily rodent eaters, but eastern (L. g. getula) and California kingsnakes (L. g. californiae) commonly feed upon snakes. Rattlesnakes have developed a defense against ophiophagous snakes known as "body bridging" in which they lift the middle portion of their body up and attempt to use it as a shield against the predator. Nevertheless, kingsnakes are often able to bite the rattlesnake behind the head, and quickly apply constricting coils, which ultimately kills the rattlesnake.
Near Royalty: Other Kingsnakes and Milk Snakes
Most members of the genus Lampropeltis—which includes a variety of kingsnakes and milk snakes—consume snakes. While most prefer lizards, prairie kingsnakes (L. calligaster), milk snakes (L. triangulum), Arizona mountain kingsnakes (L. pyromelena), California mountain kingsnakes (L. zonata), Mexican kingsnakes (L. mexicana) and gray-banded kingsnakes (L. alterna) will consume other snakes from time to time. Though specific data about their level of immunity to native pit vipers is lacking, it is likely that most exhibit some immunity to rattlesnake venom and may consume rattlesnakes.
The large snakes of the genus Drymarchon—colloquially called indigo snakes or cribos—are capable predators of rattlesnakes. Indigo snakes often inhabit gopher tortoise burrows, and eat any animals they can catch and overpower with their strong jaws. Among other prey, indigo snakes and cribos eagerly consume small rattlesnakes. Like indigo snakes and cribos, snakes of the genus Clelia attain large sizes—some grow to 9 feet or more in total length. Called mussuranas by the locals, the snakes eagerly consume other snakes—including deadly pit vipers like the fer-de-lance (Bothrops asper) and neotropical rattlesnakes (Crotalus durissus). Mussuranas incapacitate their prey by injecting venom through a pair of small fangs located in the rear of their mouth.
- Papeis Avulsos de Zoologia: The Genera Boiruna and Clelia (Serpentes: Pseudoboini) in Paraguay and Argentina
- Southeastern Naturalist: Prey Records for the Eastern Indigo Snake (Drymarchon couperi) [PDF]
- HerpNet.net: Milk Snake—Lampropeltis triangulum
- Timber Rattlesnakes in Vermont and New York: Biology, History, and the Fate of an Endangered Species; Jon Furman
- CaliforniaHerps.com: Coluber flagellum piceus—Red Racer
- Savannah River Ecology Laboratory: Eastern Kingsnake (Lampropeltis Getula)