Unit 1: Ecological Systems: 1.5.1A Brown Tree Snakes in Guam: Clue Cards 1 and 3

They floated down from the sky Sunday—2,000 mice, wafting on tiny cardboard parachutes over Andersen Air Force Base in the U.S. territory of Guam.

They floated down from the sky Sunday—2,000 mice, wafting on tiny cardboard parachutes over Andersen Air Force Base in the U.S. territory of Guam.

But the rodent commandos didn’t know they were on a mission: to help eradicate the brown tree snake, an invasive species that has caused millions of dollars in wildlife and commercial losses since it arrived a few decades ago.

But the rodent commandos didn’t know they were on a mission: to help eradicate the brown tree snake, an invasive species that has caused millions of dollars in wildlife and commercial losses since it arrived a few decades ago.

Snake traps, snake-sniffing dogs and snake-hunting inspectors have all helped control the population, but the snakes have proved especially hardy and now infest the entire island.

For some reason, the snakes are almost uniquely sensitive to acetaminophen, the active ingredient in the ubiquitous over-the-counter painkiller.

For some reason, the snakes are almost uniquely sensitive to acetaminophen, the active ingredient in the ubiquitous over-the-counter painkiller.

That’s only about one-sixth of a standard pill—pigs, dogs, and other similarly sized animals would have to eat about 500 of the baited mice to get a lethal dose.

In the last 60 years, brown tree snakes have become the embodiment of the bad things that can happen when invasive species are introduced in places where they have few predators.

A variety of other damage has been directly attributed to brown tree snakes, including large population losses among other native animal species in Guam’s forests, attacks on children and pets, and electrical power outages.

But new research by University of Washington (UW) biologists suggests that indirect impacts might be even farther reaching, possibly changing tree distributions and reducing native tree populations, altering already damaged ecosystems even further.

The snake has few predators on Guam, so its population density is quite high—estimated at more than 3,000 per square mile—and some individuals there grow to an unusual size of 10 feet long.