Southern hognose snake
- Taxon: Reptile
- Range: Alabama, Florida, Georgia, Mississippi, North Carolina, South Carolina
- Status: At-risk species, petitioned for listing on July 11, 2012; 90-day-finding that petitioned action may be warranted
First described by Carl Linneaus in 1766 from a specimen received from Charleston, South Carolina, the southern hognose snake is the smallest of the five species of hognose snakes native to North America. All belonging to the genus Heterodon, there is the eastern hognose snake (H. platirhinos; occurs throughout much of the eastern United States; overlaps with the southern hognose snake’s range), the western hognose snake (H. nasicus; occurs from southern Canada to northern Mexico through the central United States), the Mexican hognose snake (H. kennerlyi; occurs in Texas, Arizona and New Mexico), and the dusty hognose snake (H. gloydi – occurs in Texas).
The southern hognose snake is the smallest of the hognose snakes, typically ranging from 12.9-21.8 inches in length with a maximum size of 23.8 inches. Adult females tend to be longer than males but males tend to have longer tails than females. The heads of southern hognose snakes are dusky brown, short, and have sharply upturned snouts. There is a dark bar that often occurs on the snout in front of the eyes. There is also a dark brown or black stripe that occurs on either side of the neck and a short dark stripe that may occur from the rear of the eye to the corner of the mouth.
The back of the body is beige or tan with three longitudinal rows of dark brown blotches near the head and tail outlined with black and a light orange to tan stripe along the center of the back. The belly colors vary from white, cream, yellowish, or pinkish brown with a faint brownish pigment, usually near the tail. The underside of the tail is the same color as the belly, unlike Eastern hognose snakes where the tail section is lighter in color than the belly.
Hognose snakes are known for their defensive displays – hissing, flattening of their necks, and feigning death. These “theatrics” have earned them nicknames like hissing adder, blow viper, puff adder, spreading adder, and hissing sand snake. southern hognose snakes will hiss and flare their necks when threatened like other hognose snakes but tend to be less theatrical than the other species.
During the winter months, the southern hognose snake is rarely seen above ground. But its annual cycle is characterized by seasonal peaks of activity; breeding season and hatchling season. In early spring, the snakes begin to emerge from underground to breed, with mating occurring from April through August. Eggs, oval and pale in color, are laid underground from July through August and hatch approximately 60 days later. The clutch size has been reported ranging from 6-19 eggs. Hatchlings resemble adults but body color and patterning is more pronounced. Extensive foraging for food occurs during the hatchling season as snakes prepare to spend their winter months underground.
Commonly associated with the longleaf pine ecosystem, southern hognose snakes occupy very dry upland habitat with well-drained, sandy soils. They favor habitat where the canopy is open with a grassy understory.
Little is known about their underground habitat aside from the fact that they excavate their own hibernacula, burrowing more or less vertically into sandy soil in inconspicuous spots. They do not depend on stump holes or other underground chambers, although there have been recent reports of the snakes using pocket gopher mounds and gopher tortoise burrows. Three main habitat elements for the species are clear: well-drained soils, suitable vegetation structure and composition, and presence of prey.
Frogs and toads make up the largest portion of the snake’s diet. They are also known to eat small lizards. The specialized upturned snout of the hognose snake is used to dig out buried prey. As members of the genus Heterodon (meaning different tooth), hognose snakes have enlarged, ungrooved teeth in the rear of their mouths called rear fangs. Some scientists have hypothesized that those are used to puncture inflated toads and spadefoot toads. More likely, the snake is injecting mildly toxic venom into its prey. Venom, produced by a gland called the Duvernoy’s gland, exits through ducts connecting to the fang sheaths.
Native to the Coastal Plain of the southeastern United States, the southern hognose snake is known from North Carolina, South Carolina, Georgia, Florida, Alabama, and Mississippi. The range map below shows historic range, counties with known records of occurrence, and areas within the range where the species may no longer occur.
The primary concerns for the future of the southern hognose snake are habitat-based. Habitat loss, conversion and fragmentation resulting in the loss of longleaf pine savanna habitat across the range of the species are the top concerns, further exacerbated by impacts from urbanization and climate change.
Road mortalities are also a concern for the species. Snakes tend to use roads as an external source of warmth and their vulnerability to vehicle encounters increases when they travel outside of their normal home range. For southern hognose snakes, their cryptic coloration, small size, slow movement, and behavior of remaining motionless when threatened, makes them particularly susceptible to road mortality. During one survey conducted in North Carolina from 1985-2012, of the 764 southern hognose snakes detected, 643 (84%) were found dead on a road.
Invasive species are also having impacts on this snake. Red imported fire ants have been linked to population declines of several native species, including the southern hognose snake. Feral hogs are having an impact, not only through direct consumption of snakes but habitat alteration through their rooting behaviors.
Collecting individual snakes for the pet trade and the general increase in human harassment (and persecution) continues. In fact, over the last couple of decades, the number of hognose snakes in the pet trade has expanded. Western hognose snakes comprise most of the pet trade but there is evidence that collection for the pet trade is a threat for the southern hognose snake as hatchlings often sell for more than $200 at reptile shows.
Snake fungal disease, caused by the fungus Ophidiomyces ophiodiicola, is a serious emerging fungal pathogen that has been implicated in widespread snake mortalities across the Eastern United States. While there have been no documented cases of snake fungal disease in the southern hognose snake, the disease has been detected in every state within the range of the species.
Recommended conservation measures
While the species does not currently warrant listing per the Endangered Species Act, the species has been declining. In order to protect the species from unsustainable loss of viability in the future, certain conservation measures have been recommended.
- Continue habitat management and purchase of lands
- Appropriate fire management benefits the species
- Maintain contiguous parcels to ensure connectivity for genetic integrity
- Conduct standardized surveys across the species’ range
- New information
- State protections through State listing of the species
- Consider road closures where possible during peak breeding and dispersal seasons
- Conduct outreach to inform the public about the benefit of the species in the wild in order to reduce impacts from harassment, persecution and collection for the pet trade.
Partnerships, research and projects
Suitable habitat for southern hognose snakes can be found on national wildlife refuges, national forests, state lands, and other conservation areas across the species’ range. Prescribed burning and other types of habitat restoration activities on these lands have benefited the species and will further contribute towards maintaining and restoring habitat. Most conservation lands owned by federal and state agencies are expected to remain protected and managed for conservation purposes into the future.
Department of Defense
Throughout the southeast, 10 military installations have records of southern hognose snakes and an additional 26 instillations have potential for them. While no installations specifically include southern hognose snake habitat and population management prescriptions and goals within their Integrated Natural Resource Plans (INRMPs) most of the INRMPs do include specific management for other longleaf species such as the red-cockaded woodpecker and gopher tortoise, which would provide some benefit to southern hognose snakes.
America’s Longleaf Restoration Initiative
The Department of Defense, U.S. Forest Service, U.S. Fish and Wildlife Service, and multiple state agencies are all active partners in America’s Longleaf Restoration Initiative. This collaborative effort with multiple public and private sector partners actively supports range-wide efforts to restore and conserve longleaf pine ecosystems. Local Implementation Teams lead those conservation efforts and play a leading role in southern hognose snake habitat restoration and management.
Candidate Conservation Agreements with Assurances
Throughout the range of the southern hognose snake, several Candidate Conservation Agreements with Assurances (CCAAs) have been developed or are being developed. CCAAs are voluntary commitments made by non-federal partners to undertake actions that will remove or reduce threats to candidate or other at-risk species, providing net conservation benefits that have the potential to preclude the need to list a species under the Endangered Species Act. Two CCAAs in place that have the potential to benefit the southern hognose snake are the Camp Blanding Joint Training Center CCAA and The Quail County Programmatic CCAA. These agreements provide enrolled landowners with certain regulatory assurances, should a species become listed in the future.
The southern hognose snake is listed as state threatened in South Carolina and Georgia, and state endangered in Alabama and Mississippi. In North Carolina, it is ranked as a state species of special concern and in Florida is it ranked as a species of greatest conservation need.
How you can help
- Protect and restore upland habitat utilized by this snake. Maintain open characteristics of habitat through the use of prescribed fire and encourage restoration of large tracts of longleaf savanna ecosystem.
- Help avoid contributing to road mortalities by traveling cautiously through know southern hognose snake habitat during periods of peak activity (breeding season, hatchling season, and egg-laying season).
- Support research to determine the root cause of southern hognose snakes’ decline.
- Continue to inventory and monitor known populations.
- Continue outreach and education on the species.
Subject matter experts
- Melanie Olds, South Carolina Ecological Services Field Office, (843)727-4707 ext. 205, firstname.lastname@example.org
Federal Register notices
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