Brown tree snake

Brown tree snake. Photo: Queensland Government.

Brown tree snake

Photo credit: Queensland Government

Common name: brown tree snake

Scientific name: Boiga irregularis

Family: Colubridae

Conservation Status: The brown tree snake is listed as Least Concern in Queensland (Nature Conservation Act 1992).


Growing up to 2 m, this slender snake is brown with a yellow or red tinge and numerous irregular cross-bands with a cream to salmon belly. It has a broad bulbous head distinct from a narrow neck. The eyes are large with vertical cat-like pupils. It is a rear-fanged, possessing two small, grooved fangs at the rear of the mouth

Habitat and distribution

The brown tree snake can be found in forested areas, from woodlands to rainforests, as well as urban areas. They usually can be found coiled on rock faces, in tree hollows or the ground. Some are even found on rafters in buildings.

Brown tree snakes live in northern, eastern and southern Australia (up to the Sydney area). It is also found in Papua New Guinea and north western Melanesia. This snake is infamous for being an invasive species responsible for devastating the majority of the native bird population in Guam.

Life history and behaviour

The brown tree snake is nocturnal meaning it is mostly active at night. it is a skilled climber of trees, rock faces and buildings. The adults feed mainly on birds bats, eggs and small mammals, while the juveniles feed on lizards. They are egg layers, however, more studies are needed on the reproductive characteristics of the brown tree snake.

While the brown tree snake does have venom (it is rear-fanged), they don't normally harm humans. However it can strike aggressively at its prey, launching itself into a series of s-shaped loops when threatened. Bites from large individuals should be monitored carefully.

Related information

Cogger, HG 2000. Reptiles and Amphibians of Australia, 6th edition. Reed New Holland, Sydney, New South Wales.

Wilson, S 2005. A field guide to reptiles of Queensland. Reed New Holland Press, Sydney, New South Wales.

Wilson, S and Swan, G 2008. A complete guide to reptiles of Australia. Revised edition. Reed New Holland Publishers, Chatswood, New South Wales.