Eastern Hognose Snake
Heterodon platyrhinos

by Jeff LeClere

Status

Eastern hognose snakes have no special status in Minnesota.

Description

This is a medium to large Minnesota snake that may be 24 to 46 inches long and has a very stout body. It is not considered venomous. Spotted specimens have a brown or yellow ground color with darker brown or black spots. These alternate with smaller dark spots on the sides. The blotches may turn into rings on the tail. There may be red or orange pigment in the skin between the scales, and this pigment may occasionally infringe upon the scales themselves. Some populations and older adults are a solid color that may or may not have remnants of blotches. The ground color on solid individuals may be black, gray, or olive. Olive is the most common solid color phase in Minnesota. The labials are light colored on all the variations regardless of dorsal coloration.

Subspecies

There are no recognized subspecies of the eastern hognose snake, Heterodon platyrhinos.

Range

Minnesota eastern hognose snakes seem to follow the Mississippi and St. Croix Rivers, as this is the source of most of the records to date. Cass and Hubbard are the northern-most counties in which these snakes are found in Minnesota to date.

Habitat

Eastern hognose snakes are not as choosy about their habitats as their western cousins. Heavily wooded areas, prairies, and grasslands are common habitats. Like western hognose snakes, however, these snakes prefer sandy or loamy soil in which to burrow. Eastern hognose snakes are found in more damp situations as they feed heavily upon amphibians. They are also found under flippable cover (as that afforded by rocky hillsides or logs) more often than western hognoses, although still rarely.

Habits

Heterodon platyrhinos will fan its head and neck much like a cobra when alarmed. Loud and prolonged hissing is accompanied by short jabs with the head as often away from the attacker as toward it. The snake will not open its mouth to bite, and hognose snake bites originating from anger or defense are rare. If the attacker continues to press upon the hognose, it will open its mouth, writhe as if in pain and finally roll onto its back with its mouth open and tongue hanging out. It cannot be induced to move. Because the snake keeps it's mouth open during the entire "death scene" the lining at the back of the mouth closes off the opening to the esophagus to prevent the swallowing of dirt. This is also aided by an increase in saliva, which may run out of the mouth (readily seen when the snake is picked up), taking much of the dirt with it. If it is righted, it immediately rolls onto its' back again. Not until the snake feels safe will it right itself and continue on with its normal activities. Eastern hognose snakes are more elaborate with their act than the western hognoses, and even though they will perform the act in captivity for a longer period of time, they soon quit "acting" in captivity.

Eastern hognose snakes are diurnal and actively hunt for food. They may be observed basking in early morning and again at dusk. They are one of the few snakes that digs its own burrows although they do not live in them for prolonged periods of time. Logs, rocks, boards, and other cover are used-especially just before shedding. These snakes breed in the spring. They are oviparous and lay 10 - 30 eggs in a sandy area. The eggs hatch in about two months and the young are 5 - 12 inches at hatching. They are much brighter colored than the adults. H. platyrhinos hibernate from October to late April in mammal or self constructed burrows.

Food

Eastern hognose snakes consume amphibians, mainly toads, and use their snout to dig them up as toads spend much time in self made burrows. They also consume small mammals, birds, birds' eggs (ground nesters), insects, lizards, snakes, reptile eggs, and carrion. They are immune to the toxic secretions that toads produce via the partoid glands. Hognose snakes are opisthoglyphous (having fangs at the back of the mouth) and they use this feature to "deflate" toads which may puff themselves up with air to unswallowable proportions. I mentioned earlier these snakes were non-venomous, but there is some evidence that they may be mildly venomous (LeClere, 1996). Although there have been many cases of Heterodon envenomation, its toxicity is controversial. McAlister (1963) took extract from the salivary glands of H. platyrhinos and injected white mice, spring peepers, Pseudacris crucifer, Fowler's toads, Bufo woodhousei fowleri, and chorus frogs, Pseudacris triseriata in the thige obsoleta quadrivittata, and got a bad reaction from a bite from a Madagascar giant hognose snake, Leioheterodon modestus. A study conducted on a greater number of humans and different species of amphibians, reptiles, and mammals may provide better answers.