''Heterodon'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of harmless

colubrid Colubridae (, commonly known as colubrids , from , 'snake') is a family of snakes. With 249 genera, it is the largest snake family. The earliest fossil species of the family date back to the Late Eocene epoch, with earlier origins suspected. Colu ...

snake Snakes are elongated limbless reptiles of the suborder Serpentes (). Cladistically squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales much like other members of the group. Many species of snakes have s ...

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

.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 A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

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 puff adders (though they should not be confused with the

venom Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a sti ...

ous African

viper Vipers are snakes in the family Viperidae, found in most parts of the world, except for Antarctica, Australia, Hawaii, Madagascar, New Zealand, Ireland, and various other isolated islands. They are venomous and have long (relative to non-vipe ...

s of the genus ''

Bitis ''Bitis'' is a genus of Viperidae, 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 Deimatic behaviour, threat displays that invol ...

'').

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 COBRA or Cobra, often stylized as CoBrA, was a European avant-garde art group active from 1948 to 1951. The name was coined in 1948 by Christian Dotremont from the initials of the members' home countries' capital cities: Copenhagen (Co), Brussels ...

. The tail is short and the anal scale divided. The

dorsal scales In snakes, the dorsal scales are the longitudinal series of plates that encircle the body, but do not include the ventral scales. Campbell JA, Lamar WW (2004). ''The Venomous Reptiles of the Western Hemisphere''. Ithaca and London: Comstock Publis ...

are keeled with apical pits in 23-25 rows. The

rostral scale The rostral scale, or rostral, in snakes and other scaled reptiles is the median plate on the tip of the snout that borders the mouth opening. Wright AH, Wright AA (1957). ''Handbook of Snakes of the United States and Canada''. Ithaca and London: ...

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 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 which is Latin f ...

. There are 7-8 upper labials and 9-13 lower labials. The ventrals number 114–152 and the

subcaudals In snakes, the subcaudal scales are the enlarged plates on the underside of the tail. Wright AH, Wright AA (1957). ''Handbook of Snakes of the United States and Canada''. Comstock Publishing Associates, a Division of Cornell University Press. (7t ...

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

red Red is the color at the long wavelength end of the visible spectrum of light, next to orange and opposite violet. It has a dominant wavelength of approximately 625–750 nanometres. It is a primary color in the RGB color model and a seconda ...

green Green is the color between cyan and yellow on the visible spectrum. It is evoked by light which has a dominant wavelength of roughly 495570 nm. In subtractive color systems, used in painting and color printing, it is created by a com ...

s, oranges,

brown Brown is a color. It can be considered a composite color, but it is mainly a darker shade of orange. In the CMYK color model used in printing and painting, brown is usually made by combining the colors Orange (colour), orange and black. In the ...

s, to

black Black is a color that results from the absence or complete absorption of visible light. It is an achromatic color, without chroma, like white and grey. It is often used symbolically or figuratively to represent darkness.Eva Heller, ''P ...

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 as spit or drool) 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 ...

. 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 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

, 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 A mouth also referred to as the oral is the body orifice through which many animals ingest food and animal communication#Auditory, vocalize. The body cavity immediately behind the mouth opening, known as the oral cavity (or in Latin), is also t ...

open and

tongue The tongue is a Muscle, muscular organ (anatomy), organ in the mouth of a typical tetrapod. It manipulates food for chewing and swallowing as part of the digestive system, digestive process, and is the primary organ of taste. The tongue's upper s ...

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

cloaca A cloaca ( ), : cloacae ( or ), or vent, is the rear orifice that serves as the only opening for the digestive (rectum), reproductive, and urinary tracts (if present) of many vertebrate animals. All amphibians, reptiles, birds, cartilagin ...

. 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, hognose snakes are commonly mistaken to be copperheads 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. at . Accessed 31 August 2009.

Feeding

Hognose snakes live chiefly on toads and can neutralize that animal’s poisonous skin secretions physiologically.

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 (: 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. ...

Description

Behavior

Feeding

Captivity

Species

References

External links

Further reading