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Heterodon is a genus of harmless colubrid snakes endemic to North America.[1] They are stout with upturned snouts and are perhaps best known for their characteristic threat displays. Three species are currently recognized.[2] Members of the genus are commonly known as hognose snakes, hog-nosed snakes,[3] North American hog-nosed snakes,[2] and colloquially as puff adders (though they should not be confused with the venomous African vipers of the genus Bitis).
Adults grow to 30–120 cm (12–47 in) 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 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.[3]
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. 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.[4]
Hognose snakes' most distinguishing characteristic is their upturned snout, which is believed to aid in digging in sandy soils.
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 open and tongue lolling, going as far as to emit a foul musk from the cloaca. 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.[5]
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.[6]
The bulk of the Heterodon species diet is made up of rodents and lizards. H. platirhinos is an exception, and specializes in feeding on toads, having an immunity to the toxins that toads secrete.
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.
* Not including the nominate subspecies
Heterodon is a genus of harmless colubrid snakes endemic to North America. 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, North American hog-nosed snakes, and colloquially as puff adders (though they should not be confused with the venomous African vipers of the genus Bitis).
Heterodon es un género de culebras inofensivas de la familia Dipsadidae, nativas de Norteamérica, desde el norte de México hasta el sur de Canadá. Son culebras robustas con el hocico elevado.
Los adultos de estas especies crecen hasta 30 a 120 cm de longitud. El cuerpo es robusto y la cabeza es ligeramente distinta del cuello. Las costillas anteriores pueden aplanarse lo que permite ampliar el cuello cuando asume una actitud amenazante, de una forma similar al cobra. La cola es corta y las escamas dorsales son carenadas con fosas apicales en 23 a 25 filas. La escala rostral es recurvada y proyectada hacia arriba.[1]
La coloración es muy variable. H. nasicus suele tener un color arenoso con marcas blancas y negras, mientras que la coloración de H. platirhinos varía mucho dependiendo de la localidad, desde un color rojo, naranjo, marrón, hasta verde o negro. A veces son manchadas y a veces de color uniforme.
Los miembros del género Heterodon son generalmente considerados como inofensivos. Tienen dientes maxilares posteriores alargadas, dos a cada lado, y poseen una saliva ligeramente tóxica. Las mordeduras son poco frecuentes y en algunos casos involucrando a H. nasicus, los síntomas reportados mencionan un leve hormigueo, hinchazón y entumecimiento.[2]
La mayoría de los miembros de Heterodon se alimentan principalmente de roedores y lagartijas. H. platirhinos es una excepción, y se alimenta sobre todo de sapos, contando con una inmunidad a las toxinas que ellos secretan.
Se reconocen las siguientes:[3]
Heterodon es un género de culebras inofensivas de la familia Dipsadidae, nativas de Norteamérica, desde el norte de México hasta el sur de Canadá. Son culebras robustas con el hocico elevado.
Kärssmadu (Heterodon) on maoperekond.[2]
Kärssmadude perekonda klassifitseeritakse roomajate andmebaasis järgmised maoliigid[3]:
Need maod elavad Põhja-Ameerikas.
Inimestega kohtudes käituvad need maod üsna omapäraselt. "Loomade elu" 5. köites, lk 284, kirjeldatakse nende käitumist inimesega kohtudes järgmiselt: "Alguses käituvad nad väga agressiivselt ja püüavad ehmatada: lamendavad kahekordselt keha eesmise osa, laiendavad tunduvalt kaela ja pead, sisisevad valjusti ja sooritavad avatud lõugadega raevukaid sööste vaenlase poole. Kui see hirmutamine mõju ei avaldanud, kaob mao kogu agressiivsus ja hakkab peale vaatemängu teine osa: madu hakkab avatud suu ja rippuva keelega krampi kiskuma ning kui krambid lõpevad, jääb liikumatult maapinnale lamama, kõht ülespoole. Tekib täielik illusioon surmast: madu ei reageeri puudutamisele, ta keha on lõtvunud ja omandab passiivselt sellise asendi, mis talle antakse. Kuid kui eemalduda, siis tõstab madu pea üles, vaatab ringi ja teinud kindlaks, et oht möödunud, pöördub kõhule ning roomab minema.[4]
Selles artiklis on kasutatud prantsuskeelset artiklit fr:Heterodon seisuga 26.04.2014.
Heterodon Dipsadidae familiako narrasti genero bat da. Ipar Amerikan bizi dira.
Heterodon Dipsadidae familiako narrasti genero bat da. Ipar Amerikan bizi dira.
Heterodon est un genre de serpents de la famille des Dipsadidae[1].
Les espèces de ce genre se rencontrent en Amérique du Nord[1].
Les adultes mesurent de 30 à 120 centimètres selon les espèces, avec une tête bien démarquée du corps. Les couleurs sont très variables, du brun-beige-sable aux rouges, verts, orange, en fonction des espèces et des sous-espèces. Ils présentent en général des taches plus sombres sur le corps.
Les serpents de ce genre sont venimeux mais ce venin n'est pas mortel pour l'homme, et ils semblent ne s'en servir que pour se nourrir et non pour se défendre.
Ce sont des reptiles diurnes et carnivores qui consomment divers petits rongeurs, lézards ou amphibiens, Heterodon platirhinos étant spécialisé dans ce genre de proies, ayant même développé une immunité aux toxines que génèrent certaines grenouilles.
Selon Reptarium Reptile Database (9 août 2013)[2] :
Heterodon est un genre de serpents de la famille des Dipsadidae.
