Hognose

Taxobox
name = Hognose Snake

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image_caption = Eastern Hognose Snake, "Heterodon platyrhinos"
regnum = Animalia
phylum = Chordata
classis = Reptilia
ordo = Squamata
subordo = Serpentes
familia = Colubridae
subdivision_ranks = Genera
subdivision = Heterodon
Leioheterodon
Lystrophis

The hognose snake is a type of colubrid snake characterized by an upturned snout. They are notorious for playing dead when threatened. The hognose snakes consist of three distantly related genera that are artificially grouped together by the "hognose" common name: "Heterodon" which are predominantly found in United States and northern Mexico. "Leioheterodon" the Madagascar hognose snakes, and "Lystrophis" the South American or tri-colored hognose snakes.

Species

Genus "Heterodon":
*Mexican Hognose Snake, "Heterodon kennerlyi" (Kennicott, 1860)
*"Heterodon nasicus":*Dusty Hognose Snake, "Heterodon nasicus gloydi" (Edgren, 1952):*Western or Plains Hognose Snake, "Heterodon nasicus nasicus" (Baird & Girard, 1852)
*Eastern Hognose Snake, "Heterodon platirhinos" (Latreille, 1801)
*Southern Hognose Snake, "Heterodon simus" (Linnaeus, 1766)

Genus "Leioheterodon":
*Speckled Hognose Snake, "Leioheterodon geayi" (Mocquard, 1905)
*Malagasy Giant Hognose Snake, "Leioheterodon madagascariensis" (Duméril & Bibron, 1854)
*Blonde Hognose Snake, "Leioheterodon modestus" (Günther, 1863)

Genus "Lystrophis":
*South American Hognose Snake, "Lystrophis dorbignyi" (Duméril, Bibron & Duméril, 1854)
*Jan's Hognose Snake, "Lystrophis histricus" (Jan, 1863)
*"Lystrophis matogrossensis" (Scrocchi & Cruz, 1993)
*Tri-color Hognose Snake, "Lystrophis pulcher" (Jan, 1863)
*Ringed Hognose Snake, "Lystrophis semicinctus" (Duméril, Bibron & Duméril, 1854)

Description

Hognose snakes' most distinguishing characteristic is their upturned snout, which aids in digging in sandy soils by using a sweeping, side to side motion. They also like to burrow in masses of humus.

Hognose snakes are extremely variable in color and pattern. "H. nasicus" and "H. kennerlyi" tend to be sandy colored with black and white markings, while "H. platirhinos" varies from reds, greens, oranges, browns, to melanistic (i.e. black) depending on locality. They are sometimes blotched and sometimes solid-colored. "L. geayi" is a brown or tan colored snake with dark speckling on it. "L. madagascariensis" is typically green and yellow with a black checkerboard pattern along its back. "L. modestus" is normally a gold-brown color. The species in the genus "Lystrophis" are referred to as tri-color hognose snakes and sometimes as false coral snakes because they display alternating bands of red, white, and black.

"Leioheterodon" are the largest of the hognose snakes, capable of reaching lengths of 1.8 m. "H. platirhynos" gets slightly larger than other species of the genus, reaching lengths of 80 cm, where other species in the genus as well as "Lystrophis" species usually average around 65 cm at adult size.

Hognose snakes ("Heterodon") are rear-fanged and technically venomous, but the venom they excrete is not considered to be dangerous to humans and they will never bite in defense (as the only way to get bitten by a hognose snake is to smell like their prey). There has been some debate whether or not hognose are venomous, but there is evidence that their saliva has some toxicity to smaller prey items, such as toads and frogs. The fangs have been referred to as just "enlarged teeth", but they are genuine fangs that are used for venom delivery and also prey restraint. Despite the common belief, there is no evidence to support the fangs being used for "toad popping". Under this belief, the toads inflate their lungs to make swallowing difficult, but the fangs would penetrate the lungs and deflate them. However, whole toads with intact lungs are commonly regurgitated by recently captured hognoses.

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 and fecal matter from their cloaca and let their tongue hang out of their mouth, sometimes accompanied by small droplets of blood. If they are rolled upright while in this state, they will often roll back as if insisting they really are dead. It has been observed that the snake, while appearing to be dead, will still watch the animal that caused the death pose. The snake will 'resurrect' sooner if the threat is looking away from it than if the threat is looking at the snake. [cite journal | first = G.M. | last = Burghardt | coauthors = Greene, H.W. | year = 1988 | title = Predator simulation and duration of death feigning in neonate hognose snakes | journal = Animal Behaviour | volume = 36 | issue = November-December | pages = 842–44 | doi = 10.1016/10.1016/S0003-3472(88)80127-1 | accessdate = | doi_brokendate = 2008-06-22]

Diet

"Heterodon" are diurnal active foragers that typically consume their prey live without any constriction or body pinning.

For most hog nose snakes the bulk of their diet is made up by rodents, and lizards. "H. platyrhinos" is an exception, and specializes in feeding on toads although other food items such as eggs, insects and mice can make up as much as 50% of their diet.

In 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. platyrhinos" is also commonly found, but their dietary requirements can be a challenge for some keepers, and there is anecdotal evidence to suggest that feeding them a diet of exclusively rodents contributes to liver problems and a shortened life span. [ [http://www.hognose.com/pages/species/east.htm Hognose.com: Eastern Hognose Species Description] ] "Leioheterodon" species are imported regularly from Madagascar, and are not often bred in captivity and get much larger, so can pose a set of different challenges for care. "Lystrophis" species are fairly new to the commercial reptile trade, and are now commonly bred in captivity, but can be some of the more expensive hognose snakes available.

Popular culture

*The song "Copperline" by James Taylor contains the lyrics::"Half a mile down to Morgan Creek, leaning heavy on the end of the week.:Hercules and a hognosed snake, down on Copperline, we were down on Copperline." [http://www.chapelhillmuseum.org/Exhibits/Ongoing/JamesTaylorExhibit/ "Carolina on my mind: The James Taylor story,"] exhibit at the Chapel Hill Museum, Chapel Hill, North Carolina. Information retrieved 2007-12-24.]

References

External links

* [http://www.hognose.com Hognose.com]
* [http://www.albinohognose.nl Dutch Breeder of colour mutations of hognose, many pictures]
* [http://www.embl-heidelberg.de/~uetz/LivingReptiles.html The European Molecular Biology Laboratory Reptile Database]

* * [http://www.herpnet.net/Iowa-Herpetology/index.php?option=com_content&task=view&id=66&Itemid=26 Western Hognose Snake] Species account from the Iowa Reptile and Amphibian Field Guide

* * [http://www.herpnet.net/Iowa-Herpetology/index.php?option=com_content&task=view&id=49&Itemid=26 Eastern Hognose Snake] Species account from the Iowa Reptile and Amphibian Field Guide