The U.S. government dropped 2,000 mice equipped with mini parachutes made of cardboard on the Andersen Air Force Base in Guam on Sunday.
The mice were sent with the mission to eradicate the brown tree snake, which has caused trouble ever since it showed up in the 1950’s. Each of the mice, which are dead, were loaded up with a small amount of painkillers before being dropped. Painkillers are an unlikely weakness of the brown tree snake and it only takes a fraction of a pill to kill the animals, which cause an estimated $4 million in damages every year, reports NBC News.
The brown tree snakes also love to eat mice, which will be hanging in an area that is easy for the snake to reach.
“The cardboard is heavier than the tissue paper and opens up in an inverted horseshoe,” Dan Vice, the Agriculture Department’s assistant supervisory wildlife biologist for Guam, told NBC News. “It then floats down and ultimately hangs up in the forest canopy. Once it’s hung in the forest canopy, snakes have an opportunity to consume the bait.”
It only takes 72 hours for the painkillers to kill a brown tree snake.