Thelotornis kirtlandiiForest Vine Snake, Bird Snake, Twig Snake

Geographic Range

Southern Tanzania to Mozambique and Zimbabwe, south to Transvaal to northern Botswana into South West Africa and into Angola.


The bird snake lives all of its life in trees.


This oviparous species lays six to ten eggs in mid-summer. The eggs are four centimeters long by two centimeters wide. The young hatch months later at a length of 25 cm.


This shy species will retreat at almost any threat, but it is extremely vicious when cornered. The throat is inflated to create fear and surprise in enemies. It has a very elaborate swaying movement associated with prey immobilization.

Food Habits

The arboreal Bird Snake eats any small animal found in the trees, preferring lizards but also taking mice or frogs when possible. Despite its name, it seldom feeds on birds.

Economic Importance for Humans: Positive

It probably helps to control the population of arboreal rodents and lizards, playing a key role in the food web.

Economic Importance for Humans: Negative

The Bird Snake is extremely poisonous; its deadly venom causes some human deaths in its range.

Other Comments

These snakes are characterized by fangs located near the rear of the mouth. Unlike that of most of its relatives, however, the venom of the Bird Snake is quite potent, causing massive internal bleeding and lesions under the skin. A special serum was developed to combat its. Like all other members of its family, however, after biting it clings to its prey until the venom has taken affect. This species has particularly good vision, perhaps even binocular. Its colorization helps disguise it as a twig.

Although the bird snake is docile by nature and rarely bites, it should be avoided as much as possible. It has quite possibly the most potent venom of any snake in Africa, and the snake is greatly feared for that reason.


Chad H. Mummert (author), University of Michigan-Ann Arbor.



living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

native range

the area in which the animal is naturally found, the region in which it is endemic.

scrub forest

scrub forests develop in areas that experience dry seasons.


FitzSimons,V.F.M. A Field Guide to the Snakes Of Southern Africa. Cape and TransvaalPrinters (Pty) Ltd, Cape Town 1970.