Toxic Mice Dropped On Guam To Control Snakes

Toxic mice were dropped on Guam to control an overpopulation of invasive snakes. Close to 2,000 mice, laced with 80 milligrams of acetaminophen each, were dropped on two separate plots of land. The mice are expected to assist in diminishing the island's population of brown tree snakes.

The program began with an initial drop of 280 mice in 2010. Although the drops are expected to cost nearly $8 million per year, Guam officials said it is worth the cost. There are up to two million snakes on the island, and the brown tree snakes have caused some serious problems.

Although the snakes have not killed any humans, populations of small animals have diminished considerably. As they often feed on eggs, baby birds, and reptiles, the island's ecosystem has been negatively impacted. At least nine species of birds have become extinct since the snakes appeared on the island.

The snakes have also caused costly damage to Guam's power grid. As reported by, the damage prompted officials with the Guam Power Authority to place traps along fences surrounding the substations. Although nearly 8,000 snakes are caught in the traps each year, others make their way through the fences and into the substations.

Brown tree snakes are an invasive species in Guam. While their exact origin is unknown, it is believed that they were transported to the island aboard ships and on airplanes. They began appearing on the island around 60 years ago.

Dan Vice, with the US Department of Agriculture, said the toxic mice dropped on Guam will not harm other animals. The biologist said the acetaminophen dosage is enough to kill a snake.

NPR reports that the mice were dropped from planes. Several of the mice were outfitted with radio transmitters to determine whether they are eaten. If they are eaten, the radios will track the snakes' activity.

Officials said previous toxic mice drops were effective. Unfortunately it will take a lot of mice to make a dent in the island's brown tree snake population.

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