Heterodon

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Heterodon

Eastern hog-nosed snake,
Heterodon platirhinos

Scientific classification

Kingdom:	Animalia
Phylum:	Chordata
Subphylum:	Vertebrata
Class:	Reptilia
Order:	Squamata
Suborder:	Serpentes
Family:	Colubridae
Subfamily:	Xenodontinae
Genus:	Heterodon Latreille In Sonnini & Latreille, 1801

Synonyms

Boa
Coluber
Natrix
Oxyrhina
Pelias
Scytale
Scytalus
Vipera^[1]

Common names: hog-nosed snakes,^[1] North American hog-nosed snakes.^[2]

Heterodon is a genus of harmless colubrids found in North America. These are stout snakes with upturned snouts that are perhaps best known for their characteristic threat displays. Three species are currently recognized.^[2]

1 Description
2 Behavior
3 Feeding
4 Captivity
5 Species
6 Cited references
7 External links

[edit] Description

Western hog-nosed snake, H. nasicus

Adults grow to 30-120 cm in length. The body is stout and the head is slightly distinct from the neck. The latter is expandable, the anterior ribs being capable of spreading to flatten that portion of the body, something like a cobra. The tail is short and the anal scale divided. The dorsal scales are keeled with apical pits in 23-25 rows. The rostral scale is projecting, upturned, recurved and keeled dorsally. There are usually 1-20 accessory scales (azygous) that separate the internasals and the prefrontals. A subocular ring is present with 8-12 ocular scales. There are 7-8 upper labials and 9-13 lower labials. The ventrals number 114-152 and the subcaudals 27-60.^[1]

The color pattern is extremely variable. H. nasicus tends to be sandy colored with black and white markings, while H. platirhinos varies from reds, greens, oranges, browns, to black depending on locality. They are sometimes blotched and sometimes solid-colored.

Members of this genus are considered to be rear-fanged and venomous, but the venom they excrete is not considered to be dangerous to humans.^[3]

[edit] Behavior

When threatened, hognose snakes will flatten their necks and raise their heads off the ground, not unlike a cobra, and hiss. They may sometimes feign strikes, but are not apt to bite. This behaviour has earned them several nicknames, such as "puff adder", "blowing adder", "flathead", "spreading adder" or "hissing adder". Note, though, the nickname "puff adder" is only a nickname and is not scientifically correct. There is a highly venomous viper from Africa called the puff adder, Bitis arietans. If this threat display does not work to deter a would-be predator, hognose snakes will often roll onto their back and play dead, going so far as to emit a foul musk from their cloacas and let their tongue hang out of their mouths. If they are rolled upright while in this state, they will often roll back as if insisting they really are dead.

Hognose snakes' most distinguishing characteristic is their upturned snout, which is believed to aid in digging in sandy soils.

[edit] Feeding

The bulk of Heterodon diet is made up by rodents, and lizards. H. platirhinos is an exception, and specializes in feeding on toads, having an immunity to the toxins toads secrete.

[edit] Captivity

Hognose snakes are frequently found in the exotic pet trade. H. nasicus are often considered to be the easiest to care for, and captive bred stock is easily found. H. platirhinos is commonly found, but their dietary requirements can be a challenge for some keepers.

[edit] Species

Species^[2]	Authority^[2]	Subsp.*^[2]	Common name^[2]	Geographic range^[4]
H. nasicus	Baird & Girard, 1852	2	Western hog-nosed snake	Froum southeastern Alberta and northwestern Manitoba in Canada, south to southeastern Arizona and Texas in the United States and into northern Mexico. Disjunct populations in Minnesota, Iowa, Illinois, Missouri and Arkansas.
H. platirhinos	Latreille, 1801	0	Eastern hog-nosed snake	United States: eastern-central Minnesota to extreme southern New Hampshire, south to southern Florida and west to eastern Texas and western Kansas.
H. simus	(Linnaeus, 1766)	0	Southern hog-nosed snake	United States: from the coastal plain in southeast North Carolina, south to Lake Okeechobee in Florida and west to southeastern Mississippi.

*) Not including the nominate subspecies (typical form).

[edit] Cited references

^ ^a ^b ^c Wright AH, Wright AA. 1957. Handbook of Snakes. Comstock Publishing Associates. (7th printing, 1985). 1105 pp. ISBN 0-8014-0463-0.
^ ^a ^b ^c ^d ^e ^f Heterodon (TSN 174153). Integrated Taxonomic Information System. Accessed on 30 November 2006.
^ Are Hognosed Snakes Venomous? at Hognose.com. Accessed 1 December 2006.
^ Behler JL, King FW. 1979. The Audubon Society Field Guide to North American Reptiles and Amphibians. New York: Alfred A. Knopf. 743 pp. LCCCN 79-2217. ISBN 0-394-50824-6.