Outsiders may be forgiven for believing that what gives Albertans their unique identity is their aversion to a provincial sales tax and a certain fondness for turning right-wing fringe parties into formidable political forces. But no, as important as all that is, what really keeps us united is a common enemy, one that walks on four legs and boasts continuously growing incisors that can chew through anything from electrical wire to concrete.

We are approaching the 60th anniversary of Alberta's official War On Rats and, like that other war on terror, absolute victory remains elusive. So, while we all keep Canada's brave soldiers in Afghanistan in our thoughts and prayers, Albertans also pay homage to the lonely "rat patrol," a small band of provincially funded pest-control inspectors who routinely police the southern Alberta-Saskatchewan boundary, rooting out the rodents with shovels, poison and, when necessary, small-bore shotguns.

The battle lines were drawn in the summer of 1950, when Norway rats first appeared on a farm in southeastern Alberta.

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Not native to North America, the Norway rat probably arrived on the East Coast three centuries earlier aboard ships from Europe. They then made a steady march westward as the continent was settled, and were sighted in eastern Saskatchewan as early as the 1920s. But the rodents met their Waterloo as they tried to cross the next provincial boundary.

The Norway rat is, by any measure, a formidable foe. It is a prolific breeder, can gnaw through the foundations of buildings and city streets and carry infection far and wide. After all, these are the rats once linked to spreading the bubonic plague across Europe.

But Albertans were having none of that. The provincial government responded to the appearance of the Norway rat with a military-like campaign aimed at stopping the rodent in its tracks. They declared rats an official pest in 1950 and quickly established a control zone along the Alberta-Saskatchewan boundary. They required every municipality to appoint a pest-control inspector and launched a massive public education campaign.

A pair of University of Alberta researchers, Lianne McTavish and Jingjing Zheng, recently analyzed a series of anti-rat posters issued by the government during the 1950s. They found that the campaign was modelled on successful efforts during the Second World War to identify a common enemy in Nazi Germany and rally public support to defeat the Third Reich.

One typical poster informed Albertans that the rat was "a menace" to health, home and industry, and urged residents, in capital letters, to "KILL HIM!"

The U of A researchers also concluded that the government of the day viewed the rodent invasion as an opportunity to promote a common sense of provincial identity. If so, it succeeded beyond its wildest dreams.

Sure, there were some pockets of dissent. It was reported that at least one Alberta mayor didn't believe that rats represented an imminent threat and said he would eat any of the rodents that came to his town. He later demurred when presented with a bushel of rats from a local abattoir.

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But the vast majority of Albertans supported the cause and, over time, the ground battle recorded some significant victories.

The number of rat infestations in the provincial boundary area increased from one in 1950 to 573 in 1955. But by the end of the decade, a combination of bait stations, rat-proofing of buildings and removal of rat harbours and food had the enemy on the run.

Continued vigilance has paid off. Most of the rat incursions take place within 20 kilometres of the boundary, and Alberta's rat patrol has had great success in preventing further penetration.

All the same, occasional outbreaks do occur and so the best that can be said is that Alberta is "essentially" rat-free. But whenever the varmint does appear, it's clear that the urge to "KILL HIM!" remains embedded in our provincial psyche.

That's what happened in 2004 when dozens of domesticated Norway rats (which had perhaps been raised illegally as snake food by a "pet" owner) showed up in Calgary. Pest specialists called to the scene found themselves dogged by a civilian posse wielding rakes and shovels that was all too eager to take the law into its own hands.

Just last month, another Norway rat showed up in Calgary, after apparently hitching a ride on a Saskatchewan recreational vehicle. In breathless media reports, one of the province's top rodent cops was quoted talking about the "suspect rat" - much like those profilers on TV's Criminal Minds who continually mutter about "unsub" serial killers. The rat in question was duly cornered and captured.

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So let's be clear: Albertans will accept a provincial sales tax before they go soft on rats. Just don't expect either one to happen any time soon.

Brian Bergman is a Calgary-based writer and editor.