The Current

Want to fight the hordes of rats in our cities? Start with the data, expert says

Our cities may be an appealing habitat for rats, but what can we do when their numbers reach infestation levels? We hear from two women whose homes have fallen victim to a network of rat tunnels, and an expert who says our approach to eradicating them might be part of the problem.

Cities must address root causes of rodent infestations, says wildlife specialist

Donna Devlin, with a rat carcass she has just pulled from her driveway catch basin, an occurrence that she says is common. (Rob Krbavac/CBC)

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Toronto resident Dee Paul was going to check on the laundry in her basement one day when she spotted "something brown, laying on the carpet."

It was a dead rat.

"I screamed, ran back upstairs," Paul told The Current.

Hearing the commotion, her neighbour Donna Devlin rushed over. She got a plastic bag, scooped up the rat carcass, and took it outside.

"It's like changing a baby's diaper, it's not the most pleasant thing, but you've got to do it," said Devlin.

Dee Paul said that rat tunnels had led to extensive damage in her basement. (Rob Krbavac/CBC)

Both women live in Toronto's east end, and have experienced issues with rats tunnelling under their homes — and occasionally, popping up inside.

The tunnels have led to extensive damage in Paul's basement. For Devlin, the issue got so bad that she says part of her driveway collapsed.

Rat complaints in their area nearly doubled between 2017 and 2018, growing from 39 to 70. Their ward is on track to record almost 100 rat complaints by the end of this year.

Rats take toll on mental health: expert

Wildlife specialist Chelsea Himsworth said that part of the problem when dealing with rats is that we have no idea how many there are.

"I think anecdotally yes, we can agree we're having more and more people with stories exactly like this," said Himsworth, the B.C. regional director for the Canadian Wildlife Health Cooperative.

"The truth is if you look for data, there really is none."

The city of Toronto is currently doing a city-wide study on the extent of the problem, which is due by the end of the year.

Himsworth added that city officials will often only take action if there is a risk to physical health, but that rats "actually probably have a more significant impact on our mental health."

"One of the big issues is the fact that they do relentlessly invade our houses, and our houses are the one places where we should feel safe," she said.

"Living with rats can have issues ranging from anxiety to sleeplessness, avoidance of activities you usually enjoy — so they can really impact all aspects of our lives."

To understand why rats become a problem in a city, we need to look at the city itself as an overall ecosystem, said wildlife specialist Chelsea Himsworth. (Samrang Pring/Reuters)

When cities do get involved, Himsworth said they often make the mistake of looking for a "magic bullet," but that "no one thing is going to fix the problem."

"Right now, cities only become involved in really specific scenarios," she said. 

"It's highly fragmented, sort of the antithesis of a systems-based approach."

She believes we need to look at the city itself as an overall ecosystem, rather than just reacting to where rat infestations appear.

"Rather than just trap, poison, trap, poison, can we actually remove the sources? And can we target it to areas that are the most problematic?"

Click 'listen' near the top of this page to hear the full conversation.


Written by Padraig Moran. Produced by Ines Colabrese and Richard Raycraft.