Brown treesnake (Boiga irregularis) fact sheet for Pacific Island residents and travelers

The brown treesnake is an introduced species on Guam that has become a serious pest. The snakes probably arrived on Guam hidden in ship cargo from the New Guinea area, about 1100 miles to the south. The first sightings were inland from the seaport in the early 1950s. Snakes became conspicuous throughout central Guam by the 1960s, and by 1968, they had probably dispersed throughout the island.

In the absence of natural population controls and with vulnerable prey on Guam, the snakes have now become an exceptionally common pest, causing major ecological and economic damage on the island.