The lives of 2,000 mice have been sacrificed for the greater good.

The dead rodents full of painkillers were dropped Sunday onto the United States territory of Guam as part of an effort to battle the brown tree snake, a non-indigenous species that has wrought havoc on the area, NBC reported.

Equipped with tiny cardboard parachutes, the mice rained on Guam in the fourth such effort to stamp out the brown tree snake, which eats exotic native birds.

"Every time there is a technique that is tested and shows promise, we jump on that bandwagon and promote it and help out and facilitate its implementation," said Tino Aguon, acting chief of the U.S. Agriculture Department's wildlife resources office for Guam.

The snakes also cause power failures when they squirm into electric substations, costing an estimated $4 million a year in repairs and lost productivity. Likely introduced through an inadequately inspected cargo shipment in the 1950s, the species now infest the entire island.

Around 2 million of the snakes are thriving in the area, undeterred by the snake traps, snake-sniffing dogs and snake hunters that have kept the population at bay.

But government officials have found the species' weak point: Tylenol. Just a small amount of acetaminophen, the drug found in the over-the-counter painkiller, is deadly for the brown tree snake. It only takes 80 milligrams to kill one, an amount that is about one-sixth of a standard pill and wouldn't affect a dog, pig or similarly sized animal.

Pumped with acetaminophen, the mice gently fell all over Guam, dropped by helicopter. Some even had tiny data-transmitting radios so wildlife workers can track their success.

The plan was "simple," said Dan Vice, the Agriculture Department's assistant supervisory wildlife biologist for Guam.

"The cardboard is heavier than the tissue paper and opens up in an inverted horseshoe," Vice said. "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."

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