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The Eastern hog-nosed snake (Heterodon platirhinos) is a medium-sized snake with an upturned scale on the end of its snout. The scale gives the snake a pig- or hog-like appearance. In Canada, Eastern hog-nosed snakes are found in Southern Ontario south of the Canadian Shield. They are also found in the Eastern United States as far south as Florida and Texas. The Eastern hog-nosed snake is well-known for its elaborate defensive display: first, the snake flattens its neck into a cobra-like hood, and if that does not deter predators, it flips onto its back and plays dead. (See also Snake Species in Canada.)
Description
The Eastern hog-nosed snake is a medium-sized snake. Adult snakes are typically 50–85 cm in length and can grow up to a maximum of 1.16 m, with females being larger than males. The Eastern hog-nosed snake is noticeably more stout-bodied and slower-moving than other Ontario snakes, such as the common gartersnake. The feature that the hog-nosed snake is named for is the large, upturned scale on the end of its snout, which is used for digging in sandy soils.
Eastern hog-nosed snakes vary widely in colour. Their base colour can be brown, tan, grey, yellow, rust, or on the rare occasion, black. Although they are sometimes a solid colour, they often have a pattern of alternating dark blotches along their back and sides, and usually have two dark spots on their neck. The scales of the hog-nosed snake are keeled. A keeled scale has a small ridge down the middle, giving the snake an overall rough appearance rather than a shiny one.
Habitat and Distribution
Within Canada, the Eastern hog-nosed snake can only be found in Southern Ontario, specifically south of the French River and in the Carolinian forest in the province’s extreme southwestern corner. In the Eastern United States, the Eastern hog-nosed snake is found as far south as Florida and Texas, and west to Kansas.
Their preferred habitat has sandy, well-draining soil, into which they burrow using their snouts. They use these burrows as a place to sleep at night, hibernate in the winter and lay their eggs. So long as this type of soil is present, Eastern hog-nosed snakes can live in a variety of habitats, including forests, wetlands, fields, shrubland, beaches and dunes.
Reproduction and Development
Eastern hog-nosed snakes mate in both spring and fall. In late June or July, the female typically digs a burrow that reaches 7–20 cm below the surface, where she lays 7–40 eggs. After about two months, in August or September, the hatchlings emerge, each about 20 cm in length.
In Canada, Eastern hog-nosed snakes reach maturity in 3–5 years; in the southern parts of their range, they can reach maturity within two. In Canada, individuals are known to live for more than 20 years.
Diet and Predation
The primary prey of Eastern hog-nosed snakes are toads, although they will eat other prey if it is available. While hunting, they use fangs near the back of their mouth to inject their prey with a very mild venom. The placement of these fangs means that hog-nosed snakes are unable to envenomate larger animals such as humans, unless they are allowed to bite and hold on for a very long time. Even if the snake manages to envenomate a human, the chemical composition of the venom makes it non-dangerous to mammals.
Defensive Display
Eastern hog-nosed snakes are prey to other snakes and to predatory birds. They have some of the most noteworthy anti-predator defences of all Canadian snakes. When first threatened, the snake may flatten out its neck, spread out a cobra-like “hood,” lift its head and hiss loudly.
If this does not deter the predator, the snake will engage in death-feigning behaviour, or “playing dead.” It turns onto its back, writhing along the ground, and goes limp with its mouth open and tongue hanging out. It also excretes a foul odour and may additionally defecate or regurgitate food in order to appear as unappealing to a potential predator as possible. If the Eastern hog-nosed snake is turned back onto its belly while playing dead, it simply rolls over again. It remains in this position until its predator has been inactive for several minutes, at which point the snake will turn back over and slither away.
Status and Threats
The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) categorizes the Eastern hog-nosed snake as threatened, as does the country’s Species at Risk Act. Globally, the International Union for Conservation of Nature categorizes the Eastern hog-nosed snake as “least concern.”
Habitat loss and fragmentation is widespread across this snake’s range. This is especially problematic because they live in an intensely developed area of Ontario and additionally require a specific soil type. Road mortality is also an issue in developed areas, as hog-nosed snakes need to travel between suitable habitats and move quite slowly during their frequent trips across thoroughfares.
Additionally, the hog-nosed snake is commonly persecuted by humans. Humans commonly kill the snakes on sight, often mistaking the hog-nosed snake for a dangerous species, such as a venomous cobra or puff adder (neither of which are found in Canada).
