The brown rat is an extremely invasive species—a pest, that survive on human-produced garbage, usually, but often times this nasty rodent will help themselves to food meant for human consumption. Rats also carry disease. Throughout history rodent-borne diseases have caused more human death than any other epidemics on earth.
For centuries, humans have been raging a losing war against rats. In the 1930s, New York City officials tried to rid the city of its rats with mustard gas, then with a powerful anticoagulant ten years later, and again with DDT during the 1970s. Nothing worked. Then last year, the city earmarked $32 million on yet another rat eradication program. Likewise, New Zealand has vouched to make the entire archipelago rat-free by 2050.
So far, only a few rat-eradication program have been successful. Worth mentioning is the remote southern Atlantic island of South Georgia that’s home to around 100,000 pairs of Kings Penguin. The sub-Antarctic island was declared rat-free in 2018 after seven years of extensive rodent eradication operation that involved dropping of poison bait from helicopters. But the largest and perhaps the most successful rat eradication program ever undertaken was in the Canadian state of Alberta.
Alberta didn’t have a rat problem until 1950. The wild boreal forest to the north, the Rocky Mountains to the west and the semiarid High Plains of Montana to the south kept rodents away from Alberta for nearly two centuries. Only its eastern border with Saskatchewan was exposed. That year, the first rat sneaked across the state border from the neighboring Saskatchewan and took up residence in a farm in the border hamlet of Alsask. Shortly after, the intruders were discovered by the Alberta Department of Health.
Recognizing that rat infestation could have serious consequences, the Minister of Agriculture immediately set up a buffer control zone along Saskatchewan border, and a task force was organized to hunt down and kill rodents. Next, the public was educated and trained on how to recognize and eliminate rats. Most people in Alberta had never seen rats before and had to be taught how rats looked like using preserved specimens. Thousands of posters, booklets and pamphlets were distributed among the public.
Alberta Department of Public Health Rat Poster
“Because rat invasion is threatening Alberta, we need to be properly organized and know what to do, in order to fight the battle successfully,” read one booklet distributed in 1954. “No person should spare any effort to kill every Norway rat he sees,” it added.
Meanwhile the rats spread quickly, and by the fall of 1951, some 30 rat infestations were found along 180 km of Alberta's eastern border, and by 1952, the rats were active along 270 km of border. Although most infestations were within 10 to 20 km of the border, some rats had penetrated as far as 50 to 60 km inside the state.
In the first year of the rat control program, the highly potent arsenic trioxide was used to kill rats, but in 1953, safer alternatives such as warfarin, an anticoagulant, was introduced. By 1960, the number of rat infestations in Alberta had dropped to below 200 per year. In 1963, Saskatchewan initiated their own rat control program that significantly reduced the number of rats moving into Alberta. In 2002, the province finally recorded its first year with zero rat infestations, and from 2002 to 2007 only two infestations were found.
Alberta’s rat control zone shown in red. Graphics by CTV News
In 2014, the pest control program introduced a new telephone number, 310-RATS, which citizens can call to report rat sightings. Hundreds of suspected sightings are reported each year by concerned citizens, but most of these turn out to be muskrats, or gophers, or squirrels, or mice. Confirmed sightings are dealt by a SWAT-like team of pest-control officers armed with shotguns and poison pellets. Alberta is the only jurisdiction in the world to have a dedicated unit whose task is to quickly eradicate any rats who make it across the border.
Aside from responding to emergencies, the pest-control team has to periodically check each and every farm and granary within the rat control zone that stretches from the US border to the northern forests near Cold Lake, Alta. That’s more than 3,100 farms that need to be inspected annually.
Exterminated rats lie in a pile in Manitoba. Photo credit: University of Alberta
About a dozen rats are found and killed in Alberta every year, according to pest specialist Phil Merrill. Dozens more enter the state riding on the backs of commercial trucks from the U.S. and other provinces, but they almost always die unable to adapt to the different environment.
“We’ve never totally been rat-free but we don’t have a breeding population. We never have,” Phil Merrill asserts.
That’s an impressive achievement, considering the size of the province—Alberta is nearly as big as France.
Leading image by Jean-Jacques Boujot/Flickr
