Brown Tree Snake (species: Boiga irregularis) in ALA: LIRS and surrounds using records to Oct. 2021 (Lizard Island Field Guide)
Boiga irregularis
Brown Tree Snake

©Simon Gingins: Boiga irregularis at Lizard Island.

©Anne Hoggett: Brown Tree Snake at Lizard Island

©Lyle Vail: At night, Lizard Island Research Station
Kingdom Animalia
Phylum Chordata
Class Reptilia
Order Squamata
Family Colubridae
Genus Boiga
Species Boiga irregularis
Status unspecified



Distinguishing features

A long, slender, agile snake with a broad head and distinct neck. Brown above with indistinct darker bands, paler below. Large eyes with a narrow, vertical pupil.

These snakes are active at night. They can be aggressive if threatened but are not normally regarded as dangerous. However, they are weakly venomous and a bite from a large specimen could produce uncomfortable symptoms (Wilson and Swan, 2010).


  • Up to 200 cm (overall length, Wilson and Swan, 2010)



©Atlas of Living Australia: Australian distribution

Local abundance

  • Lizard Island, Queensland, Australia: Not seen frequently


Nocturnal and arboreal.

Web resources


References that assist with identification

  • Wilson, S. and G. Swan (2010). A Complete Guide to Reptiles of Australia: 3rd Edition 558 pp. New Holland Publishers, Australia.