Eastern Hog-nosed Snake

Eastern Hog-nosed Snake Joe Crowley

Eastern Hog-nosed Snake
(Heterodon platirhinos)

Other names: eastern hognose snake, Heterodon platyrhinos browni, Heterodon browni, Heterodon platyrhinos platyrhinos

The eastern hog-nosed snake, and other robust, rear-fanged snakes, were included in the family Colubridae but have recently been placed in the family Xenodontiidae.

Characteristics

The eastern hog-nosed snake has an unmistakable upturned snout, which gives this species its name. The coloration and patterning of this species is highly variable. Some individuals may have alternating dark blotches down the back and sides on a lighter background, which can be olive, tan, yellow, brown or grey. Others may lack patterning altogether and are a solid colour, usually olive or grey. Although the blotches down the back and sides may be absent on some individuals, a large blotch behind each eye is always present. This thick-bodied snake has a wide neck, which it flattens out (much like a cobra’s hood) during its defensive display. The scales of the eastern hog-nosed snake are keeled (ridged down the centre), and the underside of the tail is noticeably lighter in colour than the belly. These snakes can grow to just over a metre in length.

Similar Species

In Ontario, the eastern foxsnake, massasauga and milksnake also have blotches running down the back and sides, and the northern watersnake can have faint banding. All these species, however, lack the upturned snout, which among Ontario snakes is unique to the eastern hog-nosed snake. It is also the only snake in the province that can flatten its neck into a “hood” as a cobra does.

Habitat

The eastern hog-nosed snake inhabits fields, forests, shrubland, beaches and old dune habitats. Along the eastern shore of Georgian Bay, it can also be found in forest clearings and rock outcrops, as long as other suitable habitat is available nearby. This species is generally found in habitats with sandy, well-drained soils, into which this snake burrows. It is commonly encountered on beaches due to its affinity for open, sandy areas.

Biology

The eastern hog-nosed snake breeds in the spring and late summer. In June or July, females lay between seven and 37 eggs, although on average 10 to 18 eggs, in burrows in sandy soil, which the snake excavates with its upturned snout. This species may also deposit eggs in rotting logs or under rocks or leaves. The eggs hatch after about two months, and the young are approximately 20 centimetres in length at birth. In Ontario, eastern hog-nosed snakes reach maturity after four or five years but in warmer climates may do so in as little as two years. Individuals can live up to seven years in the wild. Eastern hog-nosed snakes hibernate underground below the frost line, often in burrows that they excavate in sandy soil. This species is not known to overwinter communally.

The eastern hog-nosed snake uses very mild venom to immobilize its prey. As it swallows its prey, the snake injects its venom through fangs at the back of its mouth. This species cannot inject venom into larger animals such as humans unless allowed to hold on (e.g., to a hand or finger) for some time. Its venom is not dangerous to humans.

When disturbed, the eastern hog-nosed snake will raise its head, flatten its neck as a cobra does, hiss loudly and lunge toward the threat. This snake keeps its mouth closed during these bluff strikes. If this impressive display does not scare away a potential predator, the snake may roll onto its back and play dead with its mouth gaping and tongue hanging out, emit a foul-smelling odour and sometimes defecate or regurgitate food. This behaviour is meant to deter predators that do not eat dead or rotten animals. If the eastern hog-nosed snake is turned over onto its belly, it will promptly flip onto its back and play dead again.

Threats & Trends

The soil characteristics of hog-nosed snake habitat predispose those sites to conversion to agricultural fields and waterfront recreational areas. As a result, much of the historic habitat of the eastern hog-nosed snake has been destroyed in southern Ontario, and remaining habitat is under constant development pressure from these human land uses. Human persecution is also a serious threat to this species. Uninformed people often kill eastern hog-nosed snakes, mistaking their defensive display for that of a dangerous species. These snakes often use beach habitats, which increases the potential for persecution because many people also use these areas. Road mortality is also a threat to this species, and high mortality rates have been documented on some roads in Ontario.

Current Status & Protection

The eastern hog-nosed snake is currently listed as Threatened under the Ontario Endangered Species Act, 2007 and Threatened under the federal Species at Risk Act. The species has also been designated as a Specially Protected Reptile under the Ontario Fish and Wildlife Conservation Act. These acts offer protection to individuals and their habitat. The habitat of this species is further protected in Ontario by the Provincial Policy Statement under the Planning Act. The International Union for Conservation of Nature lists the global status of the easternhog-nosed snake as Least Concern. The species’ status was last confirmed in January 2010. Additional detail about legal protection for species at risk in Ontario is available on our Legal Protection page.

Learn more about reptile and amphibian conservation and what you can do to help these species on our Reptile and Reptile and Amphibian Stewardship page.

 

Back to top

Range

American Bullfrog Range Map

Ontario range (click to enlarge)

In Canada, the eastern hog-nosed snake is limited to southern Ontario. Locally, the occurrence of toads, the primary food source of this snake, may limit its distribution. This species occurs throughout most of the eastern United States as far south as Florida and Texas.

Donate Now
Sign up for  E-news
JOIN US
Twitter   Facebook   YouTube   Tumblr
On Nature