The western hognose snake, Heterodon nasicus, is a small member of the colubrid snake family, ranging in size from 16 to 36 inches (about 40 to 90 cm). Also known as the puff adder, it is native to the midwestern United States but is found in parts of southern Canada and northern Mexico as well. Hognose snakes vary greatly in color, and are distinguished from other types of snakes by their stout appearance and upturned snout. Their diet consists of small rodents, amphibians and reptiles.
The snake is not considered dangerous and rarely bites people. It possesses large, grooved teeth in the rear of its mouth that carry a mild venom, which is thought to be used to subdue prey. Hognose snakes are typically not aggressive unless they are shedding, which may render them hostile.
There are numerous methods of defense that the Western hognose snake employs. At the first sign of danger, a western hognose snake will coil its tail tightly to resemble the rattle of a rattlesnake and will often inflate a hood on its neck similar to a cobra. If it still feels threatened, it will hiss loudly and strike at the offender in an attempt to frighten it off. As a last resort, the snake will play dead, rolling over on its back, usually with its mouth open and its tongue hanging out. It will not attempt to struggle if handled, but if placed on its belly, it will promptly roll onto its back again.
The western hognose snake has numerous color varieties from tan to brown or gray, with small spots down its back and two or three faint or distinct dark blotches on its sides. Most western hognose snakes have a pattern of large black spots on the underside. Active during the daytime, they are found in prairies, grasslands, and floodplains. While abundant in lowlands, they might also live as high as 8,000 feet (2,450 m) above sea level.
The species lays four to 23 thin-shelled eggs in soft, sandy soil between June and September. The young snakes hatch seven to nine weeks later. Hatchlings are between 6-7 ½" (15-19 cm) in length and reach maturity after two years.
A subspecies of the western hognose snake, the plains hognose snake, or H. n. nasicus, shares much of the same range and has a similar diet and habits. It differs in appearance by having more than 35-40 midline spots and nine or more scales between the prefrontal scales on its head.
Plains hognose snakes are found from Alberta and Manitoba in Canada southward to Texas and New Mexico in the United States. Both the plains hognose snake and western hognose snake are smaller than the similar eastern hognose snake, H. platyrhinos, which is native to most of the eastern and central United States.