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Can Vancouver use birth control to combat rat infestations in the city?

Other North American cities have deemed the practice successful.
Ottawa City Council unanimously supported a motion to ask Health Canada to review rodent birth control. Vancouver rat experts weigh in on the issue.

Vancouver continues to see rampant rat infestations across the city. Rodents can increase in staggering numbers, with females capable of producing litters of 12 pups every three weeks, meaning a pair of rats can produce up to 2,000 offspring annually. 

Other Canadian cities are currently considering creative ways to control surging rodent numbers. 

Ottawa City Council recently unanimously supported a motion to ask Health Canada to review rat fertility inhibitions (rodent birth control).

The motion also highlights that lethal rat bait poisons can be ineffective since the rodents learn what products to avoid.

College ward Coun. Laine Johnson, who tabled the unique motion, wrote in a post on X, formerly Twitter, that rat birth control has a 99 per cent success rate, making it a viable alternative for pest control management. 

Many proponents say it is also a more humane way of tackling the city's growing pest issue since it doesn't involve extermination. 

Vancouverites see rat infestations across the city

Vancouverites have shared several videos on social media of rats scurrying in packs across busy pedestrian zones, community gardens, and restaurants. Many people believe the rat population has exploded, and experts report some increased rodent numbers.

Westside Pest Control president Mike Londry told V.I.A. his company saw a surge in mouse-related calls in 2023, up a jaw-dropping 100 per cent. He also received more rat calls but said they died down later in the year.

Londry, along with many of his pest control peers, says B.C.'s ban on second-generation anticoagulant rodenticides (SGARs) has played a role in surging rodent populations. 

The Vancouver Board of Parks and Recreation says it hasn't seen an uptick in rat numbers since the ban in 2020, noting its rodent management process focuses on prevention and exclusion. 

"Exclusion measures focus on preventing rats from entering buildings such as plugging up holes, installing screen vents and door sweeps below doors," it said in a statement to V.I.A. 

"The Park Board does not use birth control for rat management as there are no registered rodent birth control products in Canada."

The City of Vancouver also provides educational materials to residents and developers on reducing the potential for rats to become established, including how keeping properties clean and well-maintained prevents them from becoming established. 

City staff monitor rat-related calls, and 1,174 issues were reported to the City through 311 in 2023. 

Vancouver rat expert weighs in on rodent management 

Health scientist Dr. Kaylee Byers has worked closely with rats for over a decade and was part of the first comprehensive study of them in Canada. 

The Vancouver Rat Project was launched in 2010 by Dr. Chelsea Himsworth to learn more about the rat population in Vancouver's Downtown Eastside, including the diseases they carry and their behaviour. 

Byers and the team captured rats, tagged their ears and collected urine, blood, and fecal samples. 

The team discovered that diseases rats carry vary drastically between city blocks because most rats don't move very far. A "happy" rat -- one that has all of its needs met, including a food source, water, an area to burrow, and access to mates -- doesn't have any reason to move...and they don't.

Across the DTES, for example, one city block could have several diseases in each rat, while rodents in the block directly beside it could be relatively disease-free. 

Poison may be effective for eliminating rodents in some indoor situations but can cause more harm than good, according to the rat expert.

In an outdoor setting, rat poison can pose a risk to the environment because animals that eat rats ingest it, such as cats and coyotes. Similarly, poison can get into water. 

Rat birth control deemed a success in major U.S. cities

Ottawa's latest motion notes that products used to reduce rat fertility were deemed "successful" in other big cities, including San Francisco and Washington, D.C. and are being trialled in New York and don't pose a risk to other animals. 

While Byers isn't particularly familiar with Evolve Soft Bait, she said the city would need to consider rat behaviour in its implementation. She mentions how she would sometimes place bait near a large garbage bin where rats were congregating and they would ignore it. They are also neophobic, meaning they fear new things in their environment. 

"It also depends on how often rats need to eat the bait for it to be effective. For some human birth control, it needs to be taken daily. If rats need to eat bait daily that likely won't happen," she told V.I.A.

Byers also notes that bait works best in closed, indoor environments. The program may also take longer but is more humane than poison. 

"We need to think thoughtfully [about the] positive and negative impacts," she mentions. 

Ottawa city councillors also highlighted that the population of rats in Ottawa increased due to factors like climate change, loss of habitat, and construction. 

Despite studying rats closely for years, Byers says no one knows Vancouver's population numbers but that it is important to include rodent control in city plans. Their populations can grow alongside humans, posing serious health implications. 

"When we are designing rat management programs, we must take a holistic approach. Not just one issue [and] more than one tool in a tool box," she notes.