CoastWise Alaska


Length with intro/outro 3:44

Download mp3 file: Rats! [3.4 MB]


They're little and furry, and deadly. They helped eradicate some 25 million people in Europe—one-third of the population—during the bubonic plague in the 1300s. Now, in the far-flung Aleutian Islands of Alaska, they've created a whole new set of problems. Of mice, or rather rats—and native wildlife—coming up next on CoastWise Alaska.


Alaska's Aleutian archipelago is a 1,500-mile-long series of rugged windswept islands that have for centuries been home to countless millions of seabirds. Most of the archipelago's 300 volcanic islands are green and lush, thanks to temperate weather and seemingly endless rainfall. And thanks also to the seabird droppings that fertilize the native grasses, flowers, and shrubs. But many of the islands have in recent years become more brown than green. On these islands, the air is eerily still. There are few seabirds. Instead, the islands teem with rats.

JOHNSON: “The biggest problem in Alaska is that they can decimate seabird populations. They are extremely effective predators on ground nesting birds. The U.S. Fish and Wildlife Service can list the islands in the Aleutians and tell you which have rats and which don't. Those that have rats don’t have seabirds.”

That's Terry Johnson, an Alaska Sea Grant Marine Advisory Program agent who's written a book aimed at helping coastal communities eliminate, or at least reduce, the number of rats in their towns.

JOHNSON: “Most coastal towns have them and they are probably flowing back and forth by a variety of means—cargo and commercial vessels probably are carrying them back and forth. Because they seem to be most common in seaports, it appears that sea traffic is their main method of distribution.”

Johnson says rats probably first arrived in Alaska two centuries ago, delivered to the coast aboard shipwrecks. Over the years, Russian, American, English, Spanish, and other vessels probably brought rats to Alaska. The biggest infestation probably occurred during World War II, when thousands of military vessels rushed to the Aleutians to defend the region from attack.

In the decades since, rats have swum or ridden on ships from island to island. The husky brownish rat, known as the Norway rat, can tip the scales at nearly a pound. They eat just about anything and can have several large litters each year.

To combat the rat scourge, state and federal authorities are working with local communities to beef up awareness and step up eradication efforts.

JOHNSON: “I think we are making some progress on both of these fronts. The awareness among harbormasters and fish plant operators is greater than it was just a couple of years ago. It's too early to say whether it has resulted in there being fewer rats. That’s a hard thing to measure.”


CoastWise Alaska is a production of the Alaska Sea Grant College Program, University of Alaska Fairbanks, which offers outreach and technical assistance to help Alaskans wisely use, conserve, and enjoy the state's marine and coastal resources. Check out our Web site at

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