World's Most Elusive Rat Caught After 18-Week Chase

It seemed like a good idea -- let a lone rat loose on a rodent-free island and then figure out how to kill it. That way, when other islands are invaded by rats, you'll know what to do. Scientists figured they'd trap the rat within days. Eighteen weeks later, they finally trapped it with some fresh penguin bait. On another island.

Rodents are a problem just about everywhere. In New Zealand, at least 11 islands have been invaded by Norway rats since 1980, in each case after rats from earlier invasions had been eradicated. The invaders disrupt local ecosystems and can kill off native species. In a new study, a Norway "city" rat was originally lured into a trap with chocolate. Its DNA was recorded, and the rat was outfitted with a radio collar and set free on the tiny island of Motuhoropapa off the coast of New Zealand. Data from the radio collar showed that the test rat traversed the entire island for about four weeks before settling on a home range.

For the next four weeks, conventional rat-trapping techniques were employed, snap traps, live traps and waxed devices, without success. After 10 weeks, the radio signal was lost. Then the researchers found rat feces on the island of Otata, 1,300 feet away across the open ocean. The DNA was a match, confirming a suspicion scientists had, that rats were good swimmers. The elusive creature had made the longest confirmed open-water crossing of any rodent in history.

Different methods were used on Otata: buried traps, peanut butter, and even trained dogs. Not until more than four months after its release was the rat finally caught, in a trap baited with fresh penguin. The scientists, led by James Russell at the University of Auckland, sagely conclude that conventional methods didn't work well. They also have an idea why: Being alone, the rat didn't behave as it would have in a rat-infested city; and with no competition for food, the bait was less attractive than it otherwise would have been.


Hmmm... I wonder if the competition for food among rats in a city works like competition in law school does for law students? I actually think it might be the polar opposite-- before law school, students are normal-ish (I mean come on-- what's normal, etc.) well-behaving (or at least socially constrained) people, but once they get into lawschool they change and become a tad "off" from the rest of the world and even amongst themselves... Thoughts?