10 Species Driven Toward Extinction by Cats

10 Species Driven Toward Extinction by Cats

Domestic cats make wonderful pets, but they're a menace to wildlife when they roam freely outdoors.

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Boris Johnson's cat Larry goes after a pigeon in London.
Larry, 10 Downing Street’s cat, chasing a pigeon.
Photo: Leon Neal (Getty Images)

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.

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Fossa

Fossa

Fossa (Cryptoprocta ferox). Duisburger Zoo
Fossa (Cryptoprocta ferox). Duisburger Zoo
Photo: Kürschner/Wikimedia Commons

The fossa (Cryptoprocta ferox) is a unique carnivorous mammal endemic to Madagascar. Unfortunately, the animal is vulnerable due to a number of factors, including habitat loss and—you guessed it—cats. Feral cats compete with the fossa for food; recently, a team of researchers got camera trap photos of cats successfully hunting lemurs and snakes in the jungles of Madagascar. Invasive cats pose a particularly worrisome problem on islands like Madagascar, where native species have evolved in isolation from many predators.

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Orange-Bellied Parrot

Orange-Bellied Parrot

One of the endangered parrots perched on a branch.
A male orange-bellied parrot in Tasmania.
Photo: Wikimedia Commons

This dazzling bird is a migratory parrot native to Australia. It’s been critically endangered since 2007, and a captive breeding program exists to help boost its numbers. But even in captivity, they aren’t safe from felines. In 2013, a cat snuck into an aviary holding the birds; according to Australia’s ABC News, a veterinarian said the birds died of head trauma, perhaps flying into walls in an attempt to get away.

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Numbat

Numbat

A Numbat at the Perth Zoo in Australia.
The endangered wombat.
Photo: Wikimedia Commons

The numbat is the endearing marsupial anteater of Australia. Looking like a cross between a squirrel and a thylacine (aka the extinct Tasmanian tiger), the numbat is endemic to Western Australia. Fewer than 1,000 individuals are thought to be alive today, and they are under threat from feral cats as well as foxes and habitat loss.

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Otago Skink

Otago Skink

The low-lying Otago skink.
An Otago skink in Nga Manu Nature Reserve in New Zealand.
Photo: Wikimedia Commons

The Otago skink is one of many reptiles in New Zealand threatened by feral cats. Island species in particular are vulnerable to invasive cats and rats. (Such was the case of the dodo, found only on the island of Mauritius. When efficient invasive predators like pigs and macaques arrived with sailors, the bird had no chance). The Otago skink can grow up to a foot long, and there may be about 2,000 still alive. Like most animals on this list, the skinks didn’t evolve to avoid predation by cats, making them easy targets.

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Sea Otter

Sea Otter

A sea otter at the Vancouver Aquarium
A sea otter at the Vancouver Aquarium
Photo: Robert Giroux (Getty Images)

Even sea otter populations may hurt by domestic cats. The Toxoplasma gondii parasite the animals carry can leach into seawater when the cats defecate. The parasite is known to sicken and kill sea otters; recent research has indicated the parasite killing the otters is coming from domestic cat populations, though an earlier study found that the parasite sickening otters more likely comes from wild sources.

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Kākāpō

Kākāpō

One of the critically endangered birds.
A kākāpō named Sirocco, who once famously tried to mate with a human head in a BBC program.
Photo: Wikimedia Commons

The feathered avocado that is the kākāpō is also endemic to New Zealand. The bird is a flightless, nocturnal parrot that is bad at sex and highly inbred. The species has managed to survive thanks to admirable conservation efforts that have been ongoing for decades. But cats like to eat the girthy birds, which cannot fly away and don’t recognize the felines as a threat.

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Key Largo Woodrat

Key Largo Woodrat

Key Largo woodrat
Key Largo woodrat
Photo: Clay DeGayner/Wikimedia Commons

The Key Largo woodrat is an endangered rodent only found in southern Florida. According to a webpage of the Fish & Wildlife Service, “A captive breeding program with the assistance of Lowery Zoo and Disney’s Animal Kingdom was conducted from 2002 until 2012 with the hope of captive releases into the wild. Unfortunately, all the released woodrats fell victim to predators, primarily feral and free-ranging cats.”

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Nene

Nene

The vulnerable nene, state bird of Hawai'i.
A nene in Kauai.
Photo: Wikimedia Commons

The nene is the official bird of Hawai’i and is endemic to the island chain. A chunky black-and-white goose, the nene was at the brink of extinction in the 1960s, with just 30 birds left in the wild, due to introduced predators including cats and mongooses. Today, the animals have rebounded, but they face another cat-borne threat: the T. gondii parasite, which is spread by cats and is linked to the deaths of nene as well as endangered Hawaiian monk seals.

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Chinese Mountain Cat

Chinese Mountain Cat

One of the endangered cats.
A Chinese mountain cat at a zoo in Xining, China.
Photo: Wikimedia Commons

Endemic to the Tibetan Plateau, the Chinese mountain cat looks a lot like a house cat but for its lynx-like ears, bushy tail and surprisingly blue eyes. The feline subspecies—Felis silvestris bieti—is genetically distinct from feral cats (Felis silvestris), but some worry that this wild animal may lose its genetic diversity as feral cats mate with it, eventually watering down the Chinese mountain cat’s genetics into oblivion.

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Florida Panther

Florida Panther

A Florida panther slinks down a tree at the Palm Beach Zoo in Florida.
An endangered Florida panther in 2019 at the Palm Beach Zoo.
Photo: Joe Raedle (Getty Images)

I know what you’re thinking: There’s no way a house cat could take down a panther. But sometimes warfare is biological. In 2008, a team of researchers reported that an outbreak of feline leukemia virus in the endangered Florida panther could be traced back to domestic cats; the outbreak killed five panthers—a significant hit, considering there are barely 200 left in the wild. While feline leukemia alone may not be the death knell for panthers, this is how extinction sometimes happens, with the compounding effects of different threats.

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