Heterodon simus
southern hog-nosed snake

The genus Heterodon is endemic to North America. Heterodon simus, the Southern Hognose Snake, is found in the southeastern United States, primarily from North and South Carolina, south to the coastal tip of Florida, and west as far as Mississippi.

Habitats often include areas of sandy woods, fields, dry river floodplains, and hardwood hammocks. They prefer loose, sandy soils and pine forests. Southern Hognose Snakes are found in temperate zones that range from a low of 20 degrees in winter to highs over 100 degrees Fahrenheit in summer months.

Heterodon simus, is a short, stoutly built snake with a pointed upturned snout and wide neck. The colors range from yellow, to light brown, or grayish, and are often tinted with colors of red. Coloration is fairly constant, not highly variable as in Eastern Hognose Snakes. The scales are keeled, and usually in rows of 25. The underside of tail is not distinctively lighter in color. The anal plate is divided in halves. This is the smallest of Heterodon species, they range in total length from 330 to 559 mm, females are usually larger than males. Heterodon means 'different tooth', which refers to the enlarged teeth on the rear of the upper jaw. These teeth inject a mild venom into their prey, and serve to puncture inflated toads like a balloon to enable ingestion. They use their blunt nose to search through leaf litter and soil for prey.

Southern Hognose Snakes are best known for their bizarre, anti-predatory behavior. Heterodon simus are sometimes called Puff Adders and "spreadheads" because they flatten their heads and necks, hiss loudly, and inflate their bodies with air, producing a show of hostility that has earned them a bad reputation. If the predator fails to retreat or further provokes these snakes, they will roll on their back, open their mouth, give a few convulsive movements, and then lie still as though dead. If these snakes are turned right side up they promptly roll over again.

Southern Hognose Snakes hibernate singly, not in hibernacula with other snakes. They are more likely than their close relatives, Eastern Hognose Snakes, to be active on cold days.

Southern Hognose Snakes eat mostly toads, primarily Scaphiopus species, and occasionally frogs and lizards.

This species has an important predatory niche in the environment. Aside from this, it rarely affects humans.

Southern Hognose Snake populations are rapidly declining throughout their range, they are believed to have been extirpated from at least two states already. Primary factors contributing to their decline include urbanization, habitat destruction, the introduction of red fire ants, increases in predation by feral cats and dogs, and pollution. Southern Hognose Snakes occupy similar habitats to Red-cockaded Woodpeckers, a federally listed endangered species. H. simus is being considered for federal listing as an endangered species.