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.
It is found from southern Arizona in the United States, through Mexico, to northern South America and Trinidad and Tobago.
This is an extremely slender snake that reaches up to 1.9 metres (6.2 ft) in length. 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.
In Arizona it is also called “pike-headed tree snake”. In Trinidad and Tobago and Guyana, it is known as a “horse whip” or “vine snake”.
Mostly arboreal and diurnal, this snake is quite often mistaken for a vine. When threatened, it sometimes releases foul smelling secretions from its vent.
It feeds mainly on lizards, but also eats frogs and birds.
O. aeneus is a mildly venomous rear-fanged snake, but it is not considered dangerous to humans. However, a bite can cause an itching sensation.
Oxybelis aeneus is oviparous. Clutch sizes of 3-6 have been published. In Arizona, hatching occurs in September.