Two million snakes have taken over the tiny island of Guam, with devastating consequences. Described by the BBC as "one of the most successful invasive species ever," the the brown tree snake is believed to have first slithered onto the 30-mile-long US territory 60 years ago, likely carried there during World War II via equipment from Papua New Guinea that was sent to Guam for processing.
"And from that handful, or maybe even one already impregnated female, we now have a population that is unbelievable in scale," said a biologist. And the brown tree snakes are wreaking havoc, showing up in people's beds and causing blackouts so frequently that power outages are known as "brown outs." Worse, they've eliminated 10 out of Guam's 12 native bird species in the past 30 years, and are now preying on small mammals. Officials are fighting back with acetaminophen-laced mice—harmless to humans, but lethal to the snakes—that are (no joke) parachuted out of helicopters. But it may be too late. (Read more brown tree snake stories.)