Southern Hognose Snake (Heterodon simus)

Description:    Southern Hognose snakes are small, heavy-bodied snakes, typically averaging about 1.5 ft (0.45 m) in length and reaching a maximum of about 2 ft (0.60 m). They have gray, tan, or red bodies with three rows of dark brown to black square blotches with one larger blotch row down the spine, and two smaller blotch rows on each side of the body. They have a cream colored belly with black mottling. They also have a variable red, yellow, or orange “stripe” that runs down the spine. Unlike the sympatric, more common eastern hognose (Heterodon platirhinos), they have a much more sharply upturned rostral (nose) scale, and are never solid black or gray. The underside of the tail is the same color as the belly.

In contrast, the eastern hognose is lighter in coloration. Southern hognose typically have a pronounced dark bar that runs between the eyes and toward the tail. This species is commonly confused with other venomous species, such as copperheads or pygmy rattlesnakes. However, the identifying “hog – nose” allows for easy identification. Scales are heavily keeled, giving a rougher texture, and the anal plate is divided.

Range & Habitat:    Southern Hognose snakes are native to the southeastern Coastal Plain from northern North Carolina and south through Florida. Historically, disjunct populations occurred in central Alabama and extreme southeastern Louisiana, but many of these populations have likely become extirpated in the past couple of decades. They can be found in upland sandhills, xeric pine-oak with wiregrass, and coastal dune habitats. The species shows a strong association with longleaf pine habitats, of which less than 3% remain. Longleaf pine provides suitable habitat with open canopies, abundant stump holes, and support for gopher tortoise populations, offering thermal gradients and refugia for hognoses. Hognose can occupy agricultural areas with sandy soils, though it is less frequently documented with H. simus.

Habits:    Southern Hognose Snakes are primarily diurnal (active during the day) surface-active snakes, with the highest surface activity from September to October, most often from late morning into early afternoon. They are seldom observed outside these windows, contributing to their reputation as “rare”. Defensively, they may flatten their necks (like a cobra), hiss, and open their mouths; however, they are less likely to “play dead” than other hognose species. Many individuals will freeze and move hesitantly, a strategy likely tied to crypsis in open, sandy habitats.

Although most hognoses are identified as toad specialists, studies indicate diets are often dominated by the six-lined racerunner (Aspidoscelis sexlineata) and the eastern spadefoot toad (Scaphiopus holbrookii) in parts of their range. They possess enlarged rear maxillary teeth and secrete toxins using specialized Duvernoy’s glands. These adaptations likely reduce prey struggling during ingestion and minimize the risk of injury to the snake’s delicate skull and jaws. In humans, bites may occasionally cause mild localized effects such as swelling or irritation, but are not medically significant. While hunting, they use their rostral scale (nose tip) to excavate buried prey items; one observation showed a hognose digging 4.5 in (11.5 cm) into packed sand to capture a spadefoot toad. In addition to their primary prey, they may also take large invertebrates, such as ox beetles (Strategus antaeus). Predation events have seldom been documented, but predators may include kingsnakes, raptors, and mesomammals.

Natural nest data are sparse for southern hognoses. Captive females construct U-shaped burrows and deposit their eggs 4-6 in (10-15 cm) deep into sandy substrates under logs or rocks. It is speculated that mating occurs in mid to late May, with eggs laid in early summer in small clutches of 6-14 eggs, and neonates emerging at 6-7 in (15-18 cm). Most neonates are encountered in September through October, indicating they hatch in early fall.

Conservation Status & Threats:    Widespread declines have been reported across the historical range, with apparent extirpations from Mississippi and Alabama, where no modern records (>30 years) exist. Primary threats include the loss and fragmentation of longleaf pine/sandhill habitat, conversion to dense pine plantations, agriculture, disruption of natural fire regimes, road mortality, and hypothesized impacts from Red Imported Fire Ants (Solenopsis invicta), particularly on eggs and neonates. It is crucial to protect large, sandy upland complexes and to maintain frequent, growing-season prescribed fire to keep an open herbaceous ground layer. In turn, this will protect the southern hognose from habitat fragmentation and road impacts. Despite extensive efforts, southern hognoses remain extremely difficult to study, underscoring the need for targeted, long-term research to better understand their natural histories and population health.

The U.S. Fish and Wildlife Service proposed listing the southern hognose as a federally threatened species, and it is protected by law in all the states where it occurs.

Pertinent References

• Jordan, R. A. 1998. Species profile: Southern Hognose Snake (Heterodon simus) on military installations in the southeastern United States. Technical Report SERDP-98-4, U.S. Army Engineer Waterways Experiment Station, Vicksburg, MS.
• Beane, J. C., K. R. Messenger, and D. L. Stephan. 2011. Natural history notes: Heterodon simus diet. Herpetological Review 42(2):292.
• Beane, J. C., S. P. Graham, T. J. Thorp, and L. T. Pusser. 2014. Natural history of the Southern Hognose Snake (Heterodon simus) in North Carolina, USA. Copeia 2014(1):168-175.