''Heterodon'' is a genus of harmless colubrid snakes endemic to

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

.Platt, Dwight R. 1983.
Heterodon
'. Catalogue of American Amphibians and Reptiles. Society for the Study of Amphibians and Reptiles, 351: 1-2. They are stout with upturned snouts and are perhaps best known for their characteristic threat displays. Three species are currently recognized. Members of the genus are commonly known as hognose snakes, hog-nosed snakes, Wright AH, Wright AA. 1957. ''Handbook of Snakes of the United States and Canada''. Ithaca and London: Comstock Publishing Associates. (7th printing, 1985). 1,105 pp. (in 2 volumes) . (Genus ''Heterodon'', p. 296 + Figure 25 on p. 81 + Map 28 on p. 298.) North American hog-nosed snakes, and colloquially as puff adders (though they should not be confused with the venomous African

viper The Viperidae (vipers) are a family of snakes found in most parts of the world, except for Antarctica, Australia, Hawaii, Madagascar, and various other isolated islands. They are venomous and have long (relative to non-vipers), hinged fangs tha ...

s of the genus ''

Bitis ''Bitis'' is a genus of venomous vipers found in Africa and the southern Arabian Peninsula. It includes the largest and the smallest vipers in the world. Members are known for their characteristic threat displays that involve inflating and defla ...

'').

Description

Adults grow to in total 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, similar to 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 In snakes, the internasal scales are those on top of the head between the scales that surround the nostrils. Wright AH, Wright AA (1957). ''Handbook of Snakes of the United States and Canada''. Ithaca and London: Comstock Publishing Associates. (7 ...

and the prefrontals. A subocular ring is present with 8-12

ocular scales In scaled reptiles, the ocular scales are those forming the margin of the eye.Wright AH, Wright AA. 1957. ''Handbook of Snakes''. Comstock Publishing Associates (7th printing, 1985). 1105 pp. . The name originates from the term ''oculus'' which ...

. There are 7-8

upper labials In reptiles, the supralabial scales, also called upper-labials, are those scales that border the mouth opening along the upper jaw. They do not include the median scaleWright AH, Wright AA. 1957. Handbook of Snakes. Comstock Publishing Associates ( ...

and 9-13 lower labials. The

ventrals In snakes, the ventral scales or gastrosteges are the enlarged and transversely elongated scales that extend down the underside of the body from the neck to the anal scale. When counting them, the first is the anteriormost ventral scale that cont ...

number 114-152 and the subcaudals 27-60. 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 have enlarged rear maxillary teeth, two on each side, and possess a slightly toxic

saliva Saliva (commonly referred to as spit) is an extracellular fluid produced and secreted by salivary glands in the mouth. In humans, saliva is around 99% water, plus electrolytes, mucus, white blood cells, epithelial cells (from which DNA can be ...

. In a few cases involving bites from '' H. nasicus'', the symptoms reported have ranged from none at all to mild tingling, swelling and itchy skin. Nevertheless, they are generally considered to be very harmless to humans. Hognose snakes' most distinguishing characteristic is their upturned snout, which is believed to aid in digging in sandy soils.

Behavior

When threatened, the hognose snake will flatten its neck and raise its head off the ground, similar to a cobra, and hiss. It may sometimes feign strikes, but is extremely reluctant to bite. This behavior has earned the hognose snake several nicknames, such as "blowing adder", "flathead", "spreading adder", or "hissing adder". If this threat display does not work to deter a would-be predator, the hognose snake will often roll onto its back and play dead with its

mouth In animal anatomy, the mouth, also known as the oral cavity, or in Latin cavum oris, is the opening through which many animals take in food and issue vocal sounds. It is also the cavity lying at the upper end of the alimentary canal, bounded on ...

open and tongue lolling, going as far as to emit a foul musk from the

cloaca In animal anatomy, a cloaca ( ), plural cloacae ( or ), is the posterior orifice that serves as the only opening for the digestive, reproductive, and urinary tracts (if present) of many vertebrate animals. All amphibians, reptiles and birds, a ...

. Emission of cloacal musk is considerably less likely than in many other species. If the snake is rolled upright while in this state, it will often roll over again as if to insist that it is really dead. Unfortunately due to their appearance and impressive

defensive display Deimatic behaviour or startle display means any pattern of bluffing ethology, behaviour in an animal that lacks strong defences, such as suddenly displaying conspicuous eyespot (mimicry), eyespots, to scare off or momentarily distract a predator ...

, hognose snakes are commonly mistaken to be

copperhead Copperhead may refer to: Snakes * ''Agkistrodon contortrix'', or copperhead, a venomous pit viper species found in parts of North America * ''Austrelaps'', or Australian copperhead, a genus of venomous elapids found in southern Australia and Tas ...

s and subsequently killed. This is especially true in the southeastern regions of the United States, where copperheads are especially prevalent by comparison to other areas it shares with the hognose.It's not a copperhead!
a
southernzombie.com
. Accessed 31 August 2009.

Feeding

The bulk of the ''Heterodon'' species diet is made up of rodents and

lizard Lizards are a widespread group of squamate reptiles, with over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic since it excludes the snakes and Amphisbaenia alt ...

s. ''H. platirhinos '' is an exception, and specializes in feeding on toads, having an immunity to the toxins that toads secrete.

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.

Species

''* Not including the

nominate subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

Description

Behavior

Feeding

Captivity

Species

References

External links

Further reading