Prior to Himsworth’s work, in fact, the sum total knowledge of Canada’s wild rats could be boiled down to a single study of 43 rats living in a landfill in nearby Richmond in 1984. So, six years ago, she stocked an old mini van with syringes, needles, and gloves and live-trapped more than 700 of V6A’s rats to sample their DNA and learn about the bacteria they carried.
Her research has made her reconsider the age-old labeling of rats as invaders that need to be completely fought back. They may, instead, be just as much a part of our city as sidewalks and lampposts. We would all be better off if, under most circumstances, we simply left them alone. [...]
Which brings into question the constant human quest to disrupt rats and their habitats. As much as rats thrive in disrupted environments, Byers says, they’ve managed to create very stable colonies within them. Rats live in tight-knit family groups that are confined to single city blocks, and which rarely interact. The Rat Project hypothesized that when a rat is ousted from its family by pest control, its family might flee its single-block territory, spreading diseases that are usually effectively quarantined to that family. In other words, the current pest control approach of killing one rat per concerned homeowner call could be backfiring, and spreading disease rather than preventing it. [...]
A significant finding from the project’s original phase, Byers tells me, is that not every rat in V6A carried the same disease. Rat families are generally confined to a single city block, and while one block might be wholly infected with a given bacteria, adjacent blocks were often completely disease free. “Disease risk doesn’t really relate to the number of rats you’re exposed to as much as it does which family you interact with,” says Robbin Lindsay, a researcher at Canada’s National Microbiology Lab who assisted the Vancouver Rat Project screen for disease. If those family units are scattered, diseases could potentially spread and multiply—something Byers is hoping to figure out through her Ph.D. work.
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