PHILADELPHIA — PETA has asked Mayor Cherelle Parker to put rats on birth control, days after City Council urged the city to treat a rat infestation in the Lower Northeast as an emergency.
The animal rights group said in a news release that it sent Parker a letter Wednesday proposing contraception in place of rat poison and traps. It asks the city to “consider the use of rat contraception programs” alongside sanitation.
“Poisoning and trapping rats is a cruel and ineffective approach that inflicts painful deaths on animals who are just trying to eke out an existence, yet fails to address what’s attracting them in the first place,” PETA President Tracy Reiman said.
The letter names no product, cost or start date, and cites no research. Published studies of one such product, ContraPest, a liquid bait that makes rats less able to breed, were written by or with its maker, SenesTech of Flagstaff, Ariz.
PETA’s letter says Baltimore, Chicago and Washington, D.C., already use contraceptive pellets or liquid bait. It also says Philadelphia was soliciting rat poison for use by city agencies as recently as 2025.
In a 2018 paper presented at a pest-control conference, SenesTech researchers reported that rat activity on six Southeast farms was 46% lower where ContraPest was used with rat poison than where poison was used alone. In two urban trials in the Midwest and Northeast, they reported rat activity fell 18% to 67%, measured with footprint plates, and that the seasonal peak was 67% lower after 133 days than at untreated sites. The farm result cites the company’s unpublished data.
A 2021 study in the journal Human–Wildlife Interactions, by a U.S. Department of Agriculture researcher and a SenesTech scientist, found that rats given a bait with the same two active ingredients in indoor pens produced significantly fewer pups. It did not test city populations.
Council adopted a resolution Oct. 8, a week after Councilmember Anthony Phillips introduced it. It urges city departments to “treat the current conditions as an urgent public health and quality-of-life emergency” in the Lower Northeast. It does not mention contraception.
Residents of Oxford Circle and Castor Gardens have reported rodents in homes, yards, businesses and vehicles, it says.
After the vote, the city departments said in a joint statement that the Department of Public Health “is well aware of the situation in the Lower Northeast and has been working with elected officials and the community from that area for most of the summer to address this situation.”
A study published in January 2025 in Science Advances tracked 7 to 17 years of public rat complaints and inspections in 16 cities, none of them Philadelphia. Rat numbers rose significantly in 11, led by Washington, D.C., San Francisco, Toronto, New York and Amsterdam, and cities that warmed more saw bigger increases.
Residents can report rats to the Health Department’s Vector Control at 215-685-9000, the city’s website says.