Oxybelis aeneus

Oxybelis aeneus, commonly known as the Mexican vine snake or brown vine snake, is a species of colubrid snake, which is endemic to the Americas.

Geographic range and habitat
O. aeneus is found from within the Atascosa, Patagonia, and Pajarito mountains of southern Arizona in the United States, through Mexico, to northern South America and Trinidad and Tobago.

Within Arizona, O. aeneus is exclusively affiliated with Madrean Evergreen Woodland communities and the upper reaches of adjacent semidesert grassland habitat. It is usually encountered in trees or shrubs on open, steep, and grassy slopes, but is also associated with wooded canyons, especially those with abundant vegetation.

Description
O. aeneus is an extremely slender snake that reaches up to 1.9 m in total length (including a long tail). Its color may vary from gray to brown with a yellow underside.



The body is laterally compressed. The snout is prominent, its length more than two times the diameter of the eye. There is 1 preocular, and there are 2 postoculars. There is 1 anterior temporal, and there are 2 posterior temporals. There is no loreal scale, and there are 8-10 upper labials.

The smooth dorsal scales are arranged in 17 rows at midbody.

Ventrals 173-205; subcaudals 150-188, divided (paired). The anal plate is divided in Arizona specimens, but is entire in South American specimens.

Common names
In Arizona O. aeneus is also called "pike-headed tree snake". In Trinidad and Tobago and Guyana, it is known as a "horse whip" or "vine snake".

Behavior
Mostly arboreal and diurnal, O. aeneus is quite often mistaken for a vine. When threatened, it sometimes releases foul smelling secretions from its vent.



Diet
O. aeneus feeds mainly on lizards (mostly anoles), but also eats frogs, small rodents and birds.

Venom
O. aeneus is a mildly venomous rear-fanged snake, but it is not considered dangerous to humans.

Reproduction
O. aeneus is oviparous. Clutch sizes of 3-6 have been published. In Arizona, hatching occurs in September.