It has been thousands of years since the first cats were domesticated, but we still don’t seem to have much control over them. Many people let their cats come and go as they please, perhaps forgetting—or not caring—that domestic cats kill billions of birds and mammals each year. Over half of pet cats in the U.S. spend time outside, and worldwide the animals have contributed to the extinction of at least 33 species, according to the U.S. Fish and Wildlife Service.
Feral cats may be the worst offenders, but pets that are allowed to roam outside also harm wildlife. The situation in Australia is so dire that officials have proposed killing some 2 million feral cats to stop their assault on endangered species. In the U.S., there are many programs aimed at reducing feral cat populations by trapping, neutering, and releasing them—but the Fish and Wildlife Service warns that such programs do not actually protect native fauna from the cats.
Sadly, it’s already too late for dozens of species, including the Stephens Island wren (a flightless songbird), the crescent nailtail wallaby, and the adorable desert bandicoot. Here, we highlight just a few of the many species currently threatened by outdoor cats.
A previous version of this article was published on November 25, 2021.