It couldn’t possibly be due to San Fran being an open sewer full of people literally shitting and peeing in the streets, right? Or all the trash, right? Or businesses fleeing the city, leaving lots of unused buildings perfect for rats to breed in, right? No, it has to be a slight increase in global temperatures over the course of 170 years
‘Infinite sea of rats’: SF’s rodent population may be exploding
The city’s climate change-driven surge in rodents puts it second only to — please don’t laugh — D.C.
Rikki Ercoli has lived off San Francisco’s Market Street for 19 years, but he never saw rats until this year. At night, he says, he glances through his bay windows and sees them scurrying. And they’re not small ones, either.
“They’re pretty fat,” Ercoli, a photographer, said. “The trash room is directly below me, and I see them running out in packs of two and three.”
Of all the urban woes that keep San Francisco residents up at night — an owner move-in eviction, losing your homeowners insurance, the Big One — few afflictions match the mundane horror of a rat infestation. Their size startles us. They make a mess. They’re embarrassing.
And their numbers may be increasing — dramatically.
Are they increasing or not? They’re writing a fearmongering article without knowing if the rat population is increasing or not.
A study of 16 major cities (14 in North America, plus Amsterdam and Tokyo) over an average of 12 years published in Science Advances last month found that climate change is fueling a hemisphere-wide population boom for Rattus rattus, or the black rat. In the case of San Francisco, the population has grown by more than 10% — more than every other city in the study besides Washington, D.C.
Yeah, that study is full of lots of mights, ifs, maybes, we thinks, based on computer models and shoddy statistics.
Jokes about a rodent infestation in the nation’s capital aside, there’s nothing funny about what’s going on here in San Francisco. Rodolfo Dirzoa, a professor of environmental science at Stanford University who was not involved in the original study, said the findings are consistent with what he sees happening in the Bay Area. He said another point in the study is hugely significant: the increasing loss of vegetation.
“The reduction of population regulation associated with the loss or decline of natural biodiversity,” Dirzo wrote via email, “creates an ideal synergy for rat proliferation.”
Well, maybe don’t cut all the trees and shrubs down. Heck, there are plenty of empty buildings that could be turned into residential.
Fragmented ecosystems give rats opportunities to thrive, causing what Dirzo calls a “rodentation” of the city. Exterminator Maria Talacona, co-founder of the Bay Area’s Mighty Men Pest Control, is all too familiar with it. “We’re definitely seeing an increase in rodent activity anywhere buildings are extremely close together,” Talacona said, adding that this living nightmare is “my favorite thing to talk about.”
An inability to walk around all four sides of a building creates spaces where humans can’t leave their scent behind. That signals that a place is safe to burrow and build nests. “It gives them a very strong advantage, because we can’t get to them.” The other pathway for an infestation is garage doors. If they don’t close tightly, rats can get inside.
So, it is a manmade issue, but, nothing to do with climate doom
Climate change, Talacona added, is very likely messing with local rats’ predators, such as raptors and garter snakes. (The carnivorous California squirrels that made headlines late last year seem content to eat only voles … for now.)
Or, it could be due to paving everything and biosphere loss. Anyhow, here we go
However, Talacona said that in her experience, the other reason for the exploding rat population is the state’s new approach to rat poison. To protect the health of birds, mountain lions, and other animals that may consume poisoned rats, Gov. Gavin Newsom signed a bill in 2024 that prohibited the use of anticoagulant rodenticides, leading the Center for Biological Diversity to crow that “California OKs strongest rat poison restrictions in nation.” Talacona likened that approach to throwing the baby out with the bathwater.
And there we go, it’s damned near impossible to do anything to stop the rats from breeding.
Read: Your Fault: San Francisco Seeing Climate (scam) Driven Rat Explosion »