The brown tree snake or Boiga irregularis originated in Australia, Indonesia and the Spice Islands. It evolved to live in the trees and feast on Australian wildlife. But sometime between World War II and 1952, brown tree snakes got onto the island of Guam. Snakes can easily slip into the cargo holds of ships or in cargo containers. That was probably how they got onto Guam, but no one is absolutely sure.
Whatever the reason for their arrival, the brown tree snake made Guam their home. They found a much easier life in Guam than in Australia. Guam never before had a snake species. Guam’s local wildlife was decimated by this flexible predator. The snakes have directly caused the extinction of the Guam rail and the Micronesian kingfisher. Nine more bird species are threatened. The birds are defenseless against tree-climbing snakes, which easily swallow eggs, hatchlings or adults. In February of 2013, the government of Guam announced that they were raining dead mice laden with arsenic into Guam’s remaining jungles in a desperate attempt to kill the snakes.
Not only have brown tree snakes eaten most of the birds, lizards, skinks and small mammals in Guam, they also are a major cause of power outages. In just the years 1978 to 1997, snakes were responsible for more than 1600 power outages. The financial cost in lost time and repairs is estimated to be several million American dollars for each of those years.
Brown tree snakes are adaptable and clever, but they cannot tell the difference between a tree and a telephone pole. They also cannot tell the difference between tree branches and power lines. All the snakes see is a pathway to easy prey. They slither onto power lines, promptly become electrocuted and cause power outages.
Brown tree snakes are venomous. The bites are usually not strong enough for the fangs to go through clothing. They need to chew in order to release all of their venom. Although no human deaths have been recorded from a brown snake bite, their venom can potentially kill babies, especially those less than 6 months old. Brown tree snakes have killed small pets, including cats.
Brown tree snakes will only bite people if they are being threatened. They do not go out of their way to bother people.
Potential Invasive Species for Hawaii
The closest American state to Guam is Hawaii, so Hawaiians in particular need to be on the lookout for the brown tree snake. The snakes may travel to Hawaii in a number of ways, including illegal pet smuggling or in cargo ships. According to the National Wildlife Federation, only seven brown tree snakes have been found in Hawaii. They were found dead or soon were killed after capture.
Although it is illegal to own any kind of snake in Hawaii, that hasn’t stopped people from purchasing brown tree snakes and other potentially destructive snake species as pets.
- · Columbia University. “Brown tree snake (Boiga irregularis).” Lisa Patrick.
- · U.S. Geological Survey. “The Brown Tree Snake on Guam.”
- · U.S. Department of Agriculture’s Animal and Plant Health Inspection Service. “Brown Tree Snake: An Invasive Reptile.” January 2011.