Snake “Nests?”
Clearing up Misconceptions
A common word I see associated with snakes is “nest.” People see several snakes and ask if there is a “nest” nearby. One prevalent myth claims that a water-skier fell into a “nest” of cottonmouths and died from dozens of bites. Seeing a snake enter or leave from a concrete foundation, crawl space, or garage often leads people to believe they have a “nest” of snakes on their property.
As a wildlife educator, my problem with the concept of a snake “nest” is that it often evokes distasteful and inaccurate images in the listener. People picture an unwanted infestation such as large numbers of disease-carrying rodents gathering in a communal brooding spot and rearing multiple litters of mice or rats. People who are fearful of snakes are often quick to jump to the conclusion that the sight of a single snake crossing their yard may indicate a large number of dangerous animals nearby. This is almost never the case.
Do snakes sometimes gather in numbers? Sure. Several species of snake will gather to mate after emerging from brumation (the reptilian version of hibernation). Often, dozens of males will be attracted by the pheromones of a female and will pile up in order to mate with her. Snakes in the U.S. which display this behavior include gartersnakes (Thamnophis) and watersnakes (Nerodia). Anaconda (Eunectes) of South America are also known for this behavior, referred to as “breeding balls.”
This behavior is the source of the “nest of cottonmouths” story that everyone seems to know of. Many people assume any snake seen in or near water is a cottonmouth (also known as a water moccasin), so when they see a mass of writhing watersnakes, a myth is born. This, however, is not a “nest.”
Many species of snake gather in numbers to overwinter in a den, including several rattlesnake species (Crotalus), copperheads (Agkistrodon), ratsnakes (Pantherophis), racers (Coluber), and others. They gather in late fall and disperse in the spring. These dens can be naturally occurring, such as rock piles on a mountainside or the root system of a fallen tree, or the den can be artificial, such as the concrete foundation of a building. Still, though, these are not “nests.”
Sometimes pitvipers such as Timber Rattlesnakes (Crotalus horridus) and Eastern Copperheads (Agkistrodon piscivorus) will gather in one area to give birth. This is referred to as a rookery or parturition site. As with the previous examples, the term “nest” is not an accurate descriptor here.
Most snakes lay their eggs (or give live birth to fully formed young) in suitable locations with no preparation or alteration (nesting). Typically, these are places like under or inside rotting logs, in rock crevices, dense vegetation, leaf piles, animal burrows, loose soil, and other naturally occurring crevices or holes. So, in the vast majority of cases, the term nest would not be remotely applicable.
A few snake species occasionally dig out their own nesting spots, such as Pinesnakes and Gophersnakes (Pituophis) and Hog-nosed Snakes (Heterodon, Leioheterodon). After laying, most species of snake leave the nest and never see their young, which are left to fend for themselves. There is some evidence that the female Madagascar Giant Hognose (Leioheterodon madagascariensis) attends her clutch of eggs.
Interestingly enough, there is a species of snake that actually does build a nest. The female King Cobra (Ophiophagus hannah), native to Southeast Asia, gathers leaves into a pile and then enters that pile to lay her clutch of eggs. Even more fascinating is that the female will actually stay and defend the nest from would-be predators, including nosy humans. After hatching, the female leaves and the baby cobras are on their own. This is a nest, but it is the exception in the snake world instead of the rule.
As I mentioned earlier, the word “nest” often evokes images of filthy masses of rodents, the walls of a home infested with ants, termites, or cockroaches, a cup-shaped mass of twigs made by a bird, or perhaps a “ball” of venomous snakes just waiting to envenomate an innocent bystander. None of these apply to snakes (except the few exceptions detailed above) but still, some people love to use the word “nest” in association with snakes in order to instill fear, spread myths, and as a justification for killing or “eradicating” them. Indeed, “snake nest” is a popular phrase used by animal removal and extermination companies.
As with most snake myths, once we examine the facts, they are quickly and easily dispelled.
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