Reptiles of North Carolina
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NC Records

Heterodon simus - Southern Hog-nosed Snake


Photo: Jeff Beane
Photo: K. Futch
Photo: K. Futch
Photo: Carla Edwards
Taxonomy
Class: Reptilia Order: Serpentes Family: COLUBRIDAE Subfamily: Dipsadinae Other Common Name(s): Southern Hognose Snake
Taxonomic Comments: Heterodon, as currently considered, consists of four species of small to medium-sized dipsadid snakes native eastern and central North America, from southern Canada to northern Mexico.

Species Comments: Heterodon simus, the Southern Hog-nosed Snake, is one of two Heterodon in North Carolina. This species is found in the southeastern United States, from North Carolina to Florida and west to Mississippi. In North Carolina, it is restricted to the Coastal Plain, though there are some records from the lower Piedmont.

No subspecies are recognized.

See the Heterodon platirhinos species account for information on past taxonomic confusion related to the Linnaean name "Coluber simus".

The generic epithet Heterodon is derived from the Greek heteros, "different", and odon, "tooth", in reference to their enlarged posterior teeth. The specific epithet simus is Latin for "flat-nosed" or "pug-nosed".

Taxonomic References: Meylan (1985).
Identification
Description: Southern Hog-nosed Snakes are small, stout-bodied snakes with a distinctive upturned snout. Their dorsal color is brown, gray, or tan, with dark brown middorsal blotches alternating with small dark dorsolateral blotches. The venter is pale whitish, often stippled with gray or brown. The coloration of the tail is similar to that of the venter. On the head, there are distinct dark stripes running from the posterior orbit to the posterior supralabial, and two large dark blotches on the back of the head to the parietals. There is also a dark transverse bar across the snout, in front of the eyes.
Morphological Features: Southern Hog-nosed Snakes have 25 keeled midbody scale rows, reducing to 21 posteriorly. Ventral counts range from 112-134 (112-132 in NC specimens; Palmer and Braswell, 1995), with 28-55 (28-49) subcaudals and typically a divided anal plate. Head scale counts are typically as follows: 8 supralabials, 10-11 infralabials, 1 loreal, 2 nasals, and 3-4+4-5 temporals. Additionally, a ring of 9-12 ocular scales are arranged in a ring around the eye, and 3-13 additional, small azygous scales may separate the prefrontals from the internasals. The rostral is prominently upturned, more so in this species than in H. platirhinos. Palmer and Braswell (1995) noted variation in scalation across multiple specimens in NC.

Southern Hog-nosed Snakes have a maximum recorded total length of 61 cm (24 inches). Palmer and Braswell (1995) reported a 57.8 cm female specimen from NC. Tail lengths account for approximately 12-23% of total length. Females reach larger sizes than males; males have longer tails, more subcaudals and tail bands and fewer ventrals. Females also tend to have more clustered scales between the internasals and prefrontals (3-13) than males (1-9).

Southern Hog-nosed Snakes have distinctly enlarged posterior teeth and Duvernoy's glands, and their secretions may produce mildly toxic effects in some people, though this has not been tested. Broadly, these snakes are not dangerous to humans or pets. Typically, this species does not bite and will not feign death as readily as its congener H. platirhinos.
Technical Reference: Palmer and Braswell (1995); Ernst and Ernst (2003).
Field Guide Descriptions: Palmer and Braswell (1995); Ernst and Ernst (2003); Beane et al. (2010).
Online Photos:    Google   iNaturalist   GBIF
Observation Methods: Southern Hog-nosed Snakes may be found out in the open during the day, under cover in burrows, or while crossing roads.
Distribution in North Carolina
County Map: Clicking on a county returns the records for the species in that county.
Key Habitat Requirements
Habitat: Southern Hog-nosed Snakes are strongly associated with xeric, pine-oak sandhills in the Coastal Plain, all with well-drained, sandy or loose loamy soils (Palmer and Braswell, 1995; Beane et al., 2010). Open fields with the same type of soils may also be used.
Biotic Relationships: Beane et al. (2014) reported that prey items of Southern Hog-nosed snakes included lizards (Aspidoscelis sexlineatus and Scincella lateralis), spadefoot toads (Scaphiopus holbrookii), and one Brown Tree Stink Bug; racerunners and spadefoot toads made up the majority of prey items. Additional prey records include various anurans (frogs and toads), fence lizards, small mammals, and an Ox Beetle larva (Ernst and Ernst, 2003; Beane et al., 2011).

Predation on Southern Hog-nosed snakes is not well documented, but they are known prey of ophiophagous snakes (Eastern Kingsnakes). Other possible predators include birds and mammals.
Life History and Autecology
Breeding and Courtship: Sexual maturity occurs at approximately 36 cm total body length. Mating occurs in the spring and summer (April to August).
Reproductive Mode: Southern Hog-nosed Snakes are oviparous and lay eggs in July that hatch in September. Clutches average 9 white, elongate eggs that average 28–30 mm long.

Hatchlings average 15 cm in total length.
Terrestrial Life History: Southern Hog-nosed Snakes are diurnal and can be found crawling abroad or across roads, but spend most of their time underground in sandy soils. In North Carolina they have been recorded from March to November; most records are from September and October, followed by May and June. During colder months they may hibernate underground by burrowing (or using a mammal burrow), but little is known about their habits.

Much remains to be learned about the natural history of this species. Home range estimates have not been reported.
General Ecology
Adverse Environmental Impacts
Status in North Carolina
NHP State Rank: S1S2
Global Rank: G2
Status in North Carolina: T

Photo Gallery for Heterodon simus - Southern Hog-nosed Snake

12 photos are shown.

Recorded by: Amy Taylor
New Hanover Co.
Comment: 		Recorded by: C Edwards
New Hanover Co.
Comment:
Recorded by: C Edwards
New Hanover Co.
Comment: 		Recorded by: Keith Farmer, C. Edwards, C. Helms
New Hanover Co.
Comment:
Recorded by: K. Futch
New Hanover Co.
Comment: 		Recorded by: K. Futch
New Hanover Co.
Comment:
Recorded by: K. Futch
New Hanover Co.
Comment: 		Recorded by: Jeff Beane
New Hanover Co.
Comment:
Recorded by: Carla Edwards
New Hanover Co.
Comment: 		Recorded by: K. Futch
New Hanover Co.
Comment:
Recorded by: K. Futch
New Hanover Co.
Comment: 		Recorded by: K. Futch
New Hanover Co.
Comment: