Western hognose snake

Species of reptile

The western hognose snake (Heterodon nasicus) is a species of snake in the family Colubridae. The species is endemic to North America. There are three subspecies that are recognized as being valid, including the nominotypical subspecies.

The specific name, nasicus, is derived from the Latin nasus ("nose"), a reference to the snake's upturned snout. The dusky hognose's subspecific name, gloydi, is in honor of American herpetologist Howard K. Gloyd (1902–1978). The Mexican hognose's subspecific (or specific) name, kennerlyi, is in honor of American naturalist Caleb Burwell Rowan Kennerly. Although bites may uncommonly be medically significant, the species is not regarded as venomous.

The western hognose snake occurs from southern Canada throughout the United States to northern Mexico. It frequents areas with sandy or gravelly soils, including prairies, river floodplains, scrub and grasslands, semi deserts, and some semiagricultural areas. Although it is more common that it will flatten its head, some individuals may puff up, filling the throat with air. This is more common with adolescent males.

In the wild, the western hognose snake feeds predominately on amphibians, such as large and medium sized tree frogs, as well as small or medium sized toads and small lizards. There have been accounts of H. nasicus eating the occasional rodent in the wild as well. Not being a true constrictor, Heterodon bites and chews, driving the rear fangs into the prey as a way of introducing the saliva to help break down the toxins from toads. There have been many cases of hognose snakes in captivity that will not eat for about two to three and a half months, from the months January to mid March. This is because hognose snakes' instinct is to brumate underground during the winter months.

Adult western hognose snakes have been observed in copulation as early as February and March. The species is oviparous, with females laying 4–23 elongate, thin shelled eggs in June–August. The eggs take approximately 60 days to hatch. Each hatchling is in total length, and reaches sexual maturity after approximately two years (this is predominantly based on size, not so much age).

SubspeciesAuthorityH. n. gloydiEdgren, 1952Gloyd's hog nosed snakeUnited States: southeastern Kansas and southeastern Missouri, eastern Oklahoma and all of Texas excluding the panhandle, the Trans Pecos and the extreme southern Rio Grande Valley. H. n. kennerlyiKennicott, 1860Mexican hog nosed snakeMexico from Tamaulipas and central San Luis Potosí, north and west along the Sierra Madre Occidental, entering the United States in the extreme southern Rio Grande Valley, the Trans Pecos, southwestern New Mexico and southeastern Arizona. H. n. nasicusBaird & Girard, 1852Plains hog nosed snakeThe Texas panhandle and adjacent New Mexico, north through western Oklahoma and Kansas to southwestern Manitoba and southeastern Saskatchewan in Canada. Also occurs in prairie regions of Minnesota and prairie relicts of Illinois.

Although some local declines have been reported, the species H. nasicus is widespread, has a large overall population size (> 100,000), and is effectively protected by a variety of conservation programs. It is therefore currently classified as Least Concern by the IUCN. The eastern hognose snake (Heterodon platirhinos) is classified as a threatened species in some regions of its range and is therefore protected under those states' laws.