Canada Province Rat-Free for 50 Years

Brian Handwerk
for National Geographic News
March 31, 2003
It is a widespread and very popular belief, that however obnoxious an
animal parasite may be, it has some compensatory feature attached to
its existence; that in nature's scheme of affairs it fulfills some
useful purpose.

A thoughtful consideration of the rat, however, fails to reveal any redeeming feature that could justify a tolerance of this highly destructive and disease-bearing pest. Perhaps in other ages and under different sanitary conditions than now exist in civilized communities the rat served as a much needed scavenger; but changing conditions have robbed the rat of even this questionable argument for existence.

A lot of things have changed since June 1919, when New Haven, Connecticut, health authorities issued these comments. But common attitudes about the rat have not.

Impressive Damage

Rats are among nature's most prolific mammalian breeders. Female rats breed up to a dozen times in a year and produce, on average, a half-dozen offspring. Some litters total 20 or more. It's estimated that the United States alone could house 150 million rats, possibly more.

To be fair, rats have made an incomparable contribution to laboratory sciences.

But when living in large numbers in close proximity to humans, the rodents take an enormous economic bite on people. They can devastate crops, food stores, and wreck havoc on buildings. Such property damage can tally billions of dollars.

Beyond such economic damage, however, rats pose health hazards. The animals harbor the lice and fleas that spawn serious diseases such as typhus, trichinosis, and infectious jaundice. In the past they've also taken the rap for outbreaks of plague—such as the catastrophic Great Plague in 17th-century London.

And attacks on humans aren't out of the picture either. (Those who recall the mass rat-on-human attacks from the original 1971 Hollywood horror film Willard should note that such scenes were made possible by actors covered in peanut-butter.)

Brown rat, house rat, barn rat, wharf rat, by any of these names the rat is the same common species: the Norway rat (Rattus norvegicus). The rodent, which grows from 12.5 to 19 inches (32 to 48 centimeters) long from nose to tail, is one of nature's most resourceful, adaptive creatures. Its diet is more varied than any other mammal, and its close relationship to humans means that Norway rats have managed to appear most everywhere that people do—whether we like it or not.

The average rat can wriggle through a hole the size of a quarter, scale a brick wall, tread water for several days, gnaw through lead pipes and cinder blocks, survive a five-story fall, survive being flushed down a toilet—and even enter a building through the same route.

It's an impressive resume for an indefatigable animal. So are we destined to live forever with rats? It would seem so, but perhaps not everywhere. In the Canadian province of Alberta, a 50-year battle has succeeded in keeping the province rat free. But it's not an easy task. To deter such a resourceful animal requires eternal vigilance.

A Search and Destroy Mission

Alberta's continuing success began with proactive measures to stop the advance of Norway rats before they entered the province.

The animals first arrived in North America in the late 18th century onboard sailing ships that frequented East Coast seaports. Once ashore, the rats marched relentlessly westward across the continent, reaching the borders of Alberta around the time of World War II.

It was then that Alberta authorities decided to declare a war of their own.

To stop the encroaching rodent population, provincial authorities established a 600- by 70-kilometer (380- by 18-mile) rat control zone along the province's vulnerable eastern border. Still of key importance, the zone remains staffed by eight dedicated professionals.

"In that buffer zone it's best described as a search and destroy mission," said John B. Bourne, a man with the official job title of "Vertebrate Pest Specialist" with Alberta Agriculture's rat control program. "It's all agricultural farmland, and in this harsher climate the rats need to live as close to humans as they possibly can. Structures and food sources are what they seek out to survive."

Bourne and his colleagues inspect everything in the zone several times a year. Rats try to gain a foothold, but are dealt with ruthlessly: hammered with poisons, fumigated with carbon monoxide-producing engines, and even individually hunted with firearms. Rat infested habitats, such as old farm buildings, are dismantled or destroyed.

Like the great armies of history, the Alberta rat hunters are aided in their policing efforts by features of the natural landscape: boreal forests in the north, the Rocky Mountains in the west, and vast prairie to the south (whose low human populations do not allow human-dependent rats to survive).

Rats are notorious travelers. And that knowledge is a source of constant worry to Bourne and his team. Will rats hitch a ride on trucks or trains and appear in Alberta's interior?

"That's probably my greater concern now: How globalization affects the rat control program," Bourne acknowledged. "We maintain and broadcast our rat-free reputation, so that Albertans know that the province is free of rats."

"We do a lot of public awareness campaigns. We have a network of people in cities and towns that are contact people should a citizen see a rat—or what he thinks is a rat—maybe in a shipment or a truck. He can immediately contact someone right. So that within a few phone calls the authorities are notified and follow-up action takes over."

Call it rapid rat response. Bourne notes that such action is called upon only a dozen times a year. "We get hundreds of reports, calls of rats in the garden, garage, on the road," he said. "Many of our citizens don't know what a rat looks like."

Bourne and his colleagues can take some credit for that fact. But given the nature of their adversary, the team can never rest on their laurels.

"They are so adaptive, so intelligent, so successful and physically capable…that it would not surprise me if they show up in a place where you'd least expect a rat to show up," he explained. "I have the greatest respect for this rodent's resourcefulness, and [its] capabilities scare the hell out of me."

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