Rat Island Missing One Thing: Rats

Norway Rat (Rattus norvegicus), Credit: CDC

Norway rats (Rattus norvegicus) came originally from Asia. They are also called sewer rats. They can be 18 inches long including a 6-inch tail. They are notoriously difficult to get rid of.

In New Zealand, at least 11 islands have been invaded by the pests since 1980, in each case after rats from earlier invasions had been eradicated. Turns out the rats are excellent swimmers, scientists discovered.

In a rather hilarious test in 2005, scientists released one Norway rat on a rodent-free island in an effort to figure out how to kill it, so as to inform future efforts. Eighteen weeks later, they finally trapped the elusive rat with some fresh penguin bait. On another island 1,300 feet (400 meters) away.

Which brings us to Alaska.

Sometime before 1780, an island in the Aleutian chain became inundated with Norway rats when a rat-infested Japanese ship crashed there. The island, now part of Alaska, has been a rat haven ever since and came to be known as Rat Island.

In 2007, the U.S. Fish & Wildlife Service started working on a plan to eradicate the Aleutian island infiltrators.

Here's the thing: Norway rats can pass through an opening of just 1/2-inch, scale a brick wall, and survive being flushed down a toilet.

Ultimately, the Rat Island eradicators dropped poison from buckets hoisted by helicopters.

Apparently it worked, officials said this week. No signs of rats. Birds are returning to the island to nest. For now.