Rat snake

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Colubrids

A rat snake in Istanbul.
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Reptilia
Subclass: Diapsida
Infraclass: Lepidosauromorpha
Superorder: Lepidosauria
Order: Squamata
Infraorder: Serpentes
Family: Colubridae
Genus: Elaphe

Rat snakes are a large, polyphyletic, group of snakes from the Colubrid subfamily Colubrinae. Many species tend to be very skittish and sometimes aggressive but bites are usually superficial. They were long thought to be nonvenomous, but recent studies have shown that at least some species do possess venom. A variety of species like Elaphe guttata guttata are known for the ease with which they are tamed and are common in the pet trade. There is considerable variation between different types of rat snake but most are medium to large, rodent eating snakes.

Previously most were assigned to the genus Elaphe but many have been since renamed. The validity of some genera is debatable but for the purpose of this article a more liberal taxonomic stance will be taken. Rat snakes have traditionally been divided into two groups, New World and Old World species.

Black Rat Snake Elaphe obsoleta obsoleta. Note the blue eyes indicating that the snake is in a shed cycle.

It is worth noting that, though the polyphyletic nature of the genus is almost undisputed, many species are conservatively referred to as Elaphe sp. See, for instance, Black Rat Snake and Grey Rat Snake, subspecies of Elaphe obsoletus.

Examples of snakes found in the Elaphe include:

Yellow rat snake Elaphe obsoleta quadrivittata.

[edit] New World Rat Snakes

New World rat snakes belong to the Colubrine tribe Lampropeltinae, and as such are closely related to Lampropeltis (milk snakes and king snakes), Pituophis (gopher snakes, pine snakes and bull snakes), Rhinocheilus (longnose snakes), Arizona (glossy snakes) and Stilosoma (short-tailed snakes). The entire Lampropeltinid group is descended from Old World rat snakes that crossed the Bering Land Bridge sometime within the last twenty to thirty million years.

The New World rat snakes consist of the genera Bogertophis (Trans Pecos and Baja rat snakes), Elaphe (Corn snakes, Fox snakes and American rat snakes), Pseudelaphe (Central American rat snake) and Senticolis (Green rat snake).

[edit] Rat Snakes

The Genera Elaphe, Euprepiophis, Oreophis, Orthriophis, Ptyas, Rhinechis, and Zamenis constitute Old-World rat snakes. See also: Persian Ratsnake

[edit] External links

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