Species Fact Profile: Brown Tree Snake (Boiga irregularis)

Brown Tree Snake

Boiga irregularis (Merrem, 1802)

Range: Northern Australia, New Guinea, Indonesia, Solomon Islands, Guam (Introduced)
Habitat: Tropical Forest
Diet: Frogs, Lizards, Birds, Eggs, Bats
Social Grouping: Asocial (will share refuges)
Lifespan: 13 Years (Captivity)
Reproduction: May breed year round in wetter portions of range, females have sperm storage abilities, 4-12 eggs deposited in hollow logs, rock crevice, or other hiding place; they hatch between 76-90 days later.  The age of sexual maturity depends on body length
Conservation Status: Not Listed

• Body length varies across range, but snakes from the introduced population of Guam achieve the greatest length at over 3 meters.  The snake is long and slender with a proportionately large head
• Wide range of color morphs, including the namesake brown-yellow, as well as blue-and-white or red-and-white banding
• Most active by night, the snakes have large eyes with elliptical vertical pupils, sometimes giving them the nickname of "cat snakes"; daytime hours are often spent inactive under rocks, in crevices, or in dense vegetation
• Primarily arboreal, but also known to forage on the ground or enter grasslands or clearings while crossing from one patch of habitat to another
• Species is mildly venomous (the venom is neurotoxic), with two small, grooved fangs located at the rear of the mouth.  Snakes that are threatened will rear up in a threatening position, but bites on humans are uncommon
• The brown tree snake was first detected in Guam in the 1950's, presumably accidentally imported in military cargo during World War II.  Since then, the snake has wrecked havoc on the predator-naive native bird-life, driving many Guam species to extinction or extirpation