Common names: hog-nosed snakes, North American hog-nosed snakes.

Heterodon is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of harmless colubrid

Colubrid

A colubrid is a member of the snake family Colubridae. This broad classification of snakes includes about two-thirds of all snake species on earth. The earliest species of the snake family date back to the Oligocene epoch. With 304 genera and 1,938 species, Colubridae is the largest snake family...

s found in North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

. They are stout with upturned snouts and are perhaps best known for their characteristic threat displays. Three species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 are currently recognized.

Description

Adults grow to 30-120 cm (12-47 in.) 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, similar to a cobra

Naja

Naja is a genus of venomous elapid snakes. Although there are several other genera that share the common name, Naja are the most recognized and most widespread group of snakes commonly known as cobras. The genus Naja consists of 20 to 22 species, but has undergone several taxonomic revisions in...

. The tail is short and the anal scale

Anal scale

In snakes, the anal scale is the scale just in front of and covering the cloacal opening. This scale can be either single or paired . When paired, the division is oblique. It is preceded by the ventral scales and followed by the subcaudal scales....

 divided. The dorsal scales

Dorsal scales

In snakes, the dorsal scales are the longitudinal series of plates that encircle the body, but do not include the ventral scales.When counting dorsal scales, numbers are often given for three points along the body, for example 19:21:17...

 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

Ocular scales

In scaled reptiles, the ocular scales are those forming the margin of the eye. The name originates from the term oculus which is Latin for "eye" and, in the broadest sense, refers to a scale associated with the eye...

. There are 7-8 upper labials and 9-13 lower labials. The ventrals number 114-152 and the subcaudals 27-60.

The color pattern is extremely variable. H. nasicus

Heterodon nasicus

Heterodon nasicus is a harmless colubrid species found in North America and northern Mexico. Three subspecies are currently recognized, including the typical form described here.-Description:...

 tends to be sandy-colored with black and white markings, while H. platirhinos varies from red

Red

Red is any of a number of similar colors evoked by light consisting predominantly of the longest wavelengths of light discernible by the human eye, in the wavelength range of roughly 630–740 nm. Longer wavelengths than this are called infrared , and cannot be seen by the naked eye...

s, green

Green

Green is a color, the perception of which is evoked by light having a spectrum dominated by energy with a wavelength of roughly 520–570 nanometres. In the subtractive color system, it is not a primary color, but is created out of a mixture of yellow and blue, or yellow and cyan; it is considered...

s, oranges, brown

Brown

Brown is a color term, denoting a range of composite colors produced by a mixture of orange, red, rose, or yellow with black or gray. The term is from Old English brún, in origin for any dusky or dark shade of color....

s, to black

Black

Black is the color of objects that do not emit or reflect light in any part of the visible spectrum; they absorb all such frequencies of light...

 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

Saliva , referred to in various contexts as spit, spittle, drivel, drool, or slobber, is the watery substance produced in the mouths of humans and most other animals. Saliva is a component of oral fluid. In mammals, saliva is produced in and secreted from the three pairs of major salivary glands,...

. In a few cases involving bites from H. nasicus

Heterodon nasicus

Heterodon nasicus is a harmless colubrid species found in North America and northern Mexico. Three subspecies are currently recognized, including the typical form described here.-Description:...

, the symptoms reported have ranged from none at all to mild tingling, swelling and numbness. Nevertheless, they are generally considered to be harmless.

Behavior

When threatened, the hognose snake will flatten its neck and raise its head off the ground, similar to a cobra

Cobra

Cobra is a venomous snake belonging to the family Elapidae. However, not all snakes commonly referred to as cobras are of the same genus, or even of the same family. The name is short for cobra capo or capa Snake, which is Portuguese for "snake with hood", or "hood-snake"...

, and hiss. It may sometimes feign strikes, but is extremely reluctant to bite. This behavior has earned the hognose 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

Mouth

The mouth is the first portion of the alimentary canal that receives food andsaliva. The oral mucosa is the mucous membrane epithelium lining the inside of the mouth....

 open and tongue

Tongue

The tongue is a muscular hydrostat on the floors of the mouths of most vertebrates which manipulates food for mastication. It is the primary organ of taste , as much of the upper surface of the tongue is covered in papillae and taste buds. It is sensitive and kept moist by saliva, and is richly...

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

Cloaca

In zoological anatomy, a cloaca is the posterior opening that serves as the only such opening for the intestinal, reproductive, and urinary tracts of certain animal species...

. 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.

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

Unfortunately due to their appearance and impressive defensive display, hognose snakes are commonly mistaken to be copperhead

Copperhead

Copperhead may refer to:Snakes:* Agkistrodon contortrix, a venomous pit viper species found in parts of North America.* Agkistrodon piscivorus, a.k.a. the cottonmouth, another venomous pit viper species found in North America....

s and subsequently killed. This is especially true in the south-eastern regions of the United States.

Feeding

The bulk of Heterodon diet is made up of rodent

Rodent

Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....

s, and lizard

Lizard

Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...

s. H. platirhinos is an exception, and specializes in feeding on toad

Toad

A toad is any of a number of species of amphibians in the order Anura characterized by dry, leathery skin , short legs, and snoat-like parotoid glands...

s, having an immunity to the toxins 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

Species	Authority	Subsp.*	Common name	Geographic range
H. nasicus Heterodon nasicus Heterodon nasicus is a harmless colubrid species found in North America and northern Mexico. Three subspecies are currently recognized, including the typical form described here.-Description:...	Baird Spencer Fullerton Baird Spencer Fullerton Baird was an American ornithologist, ichthyologist and herpetologist. Starting in 1850 he was assistant-secretary and later secretary of the Smithsonian Institution in Washington, D.C...  & Girard Charles Frédéric Girard Charles Frédéric Girard was a French biologist specializing in ichthyology and herpetology.Born in Mulhouse, France, he studied at the College of Neuchâtel, Switzerland as a student of Louis Agassiz. In 1847, he accompanied Agassiz as his assistant to Harvard... , 1852	2	Western hog-nosed snake	Southeastern Alberta Alberta Alberta is a province of Canada. It had an estimated population of 3.7 million in 2010 making it the most populous of Canada's three prairie provinces...  and northwestern Manitoba Manitoba Manitoba is a Canadian prairie province with an area of . The province has over 110,000 lakes and has a largely continental climate because of its flat topography. Agriculture, mostly concentrated in the fertile southern and western parts of the province, is vital to the province's economy; other...  in Canada Canada Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean... , south to southeastern Arizona Arizona Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...  and Texas Texas Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...  in the United States United States The United States of America is a federal constitutional republic comprising fifty states and a federal district...  and into northern Mexico Mexico The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of... . Disjunct populations in Minnesota Minnesota Minnesota is a U.S. state located in the Midwestern United States. The twelfth largest state of the U.S., it is the twenty-first most populous, with 5.3 million residents. Minnesota was carved out of the eastern half of the Minnesota Territory and admitted to the Union as the thirty-second state... , Wisconsin Wisconsin Wisconsin is a U.S. state located in the north-central United States and is part of the Midwest. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michigan to the northeast, and Lake Superior to the north. Wisconsin's capital is... , Iowa Iowa Iowa is a state located in the Midwestern United States, an area often referred to as the "American Heartland". It derives its name from the Ioway people, one of the many American Indian tribes that occupied the state at the time of European exploration. Iowa was a part of the French colony of New... , Illinois Illinois Illinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,... , Missouri Missouri Missouri is a US state located in the Midwestern United States, bordered by Iowa, Illinois, Kentucky, Tennessee, Arkansas, Oklahoma, Kansas and Nebraska. With a 2010 population of 5,988,927, Missouri is the 18th most populous state in the nation and the fifth most populous in the Midwest. It...  and Arkansas Arkansas Arkansas is a state located in the southern region of the United States. Its name is an Algonquian name of the Quapaw Indians. Arkansas shares borders with six states , and its eastern border is largely defined by the Mississippi River... .
H. platirhinos	Latreille Pierre André Latreille Pierre André Latreille was a French zoologist, specialising in arthropods. Having trained as a Roman Catholic priest before the French Revolution, Latreille was imprisoned, and only regained his freedom after recognising a rare species he found in the prison, Necrobia ruficollis... , 1801	0	Eastern hog-nosed snake	United States: eastern-central Minnesota to extreme southern New Hampshire New Hampshire New Hampshire is a state in the New England region of the northeastern United States of America. The state was named after the southern English county of Hampshire. It is bordered by Massachusetts to the south, Vermont to the west, Maine and the Atlantic Ocean to the east, and the Canadian... , south to southern Florida Florida Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...  and west to eastern Texas and western Kansas Kansas Kansas is a US state located in the Midwestern United States. It is named after the Kansas River which flows through it, which in turn was named after the Kansa Native American tribe, which inhabited the area. The tribe's name is often said to mean "people of the wind" or "people of the south... .
H. simus Heterodon simus Heterodon simus is a harmless snake species found in the southeastern United States. No subspecies are currently recognized.-Description:Adults are 35.5-61 cm in length. Stout with a wide neck and a sharply upturned snout...	(Linnaeus Carolus Linnaeus Carl Linnaeus , also known after his ennoblement as , was a Swedish botanist, physician, and zoologist, who laid the foundations for the modern scheme of binomial nomenclature. He is known as the father of modern taxonomy, and is also considered one of the fathers of modern ecology... , 1766)	0	Southern hog-nosed snake	United States: from the coastal plain in southeast North Carolina North Carolina North Carolina is a state located in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north. North Carolina contains 100 counties. Its capital is Raleigh, and its largest city is Charlotte... , south to Lake Okeechobee Lake Okeechobee Lake Okeechobee , locally referred to as The Lake or The Big O, is the largest freshwater lake in the state of Florida. It is the seventh largest freshwater lake in the United States and the second largest freshwater lake contained entirely within the lower 48 states...  in Florida and west to southeastern Mississippi Mississippi Mississippi is a U.S. state located in the Southern United States. Jackson is the state capital and largest city. The name of the state derives from the Mississippi River, which flows along its western boundary, whose name comes from the Ojibwe word misi-ziibi... .

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