One of the world’s most invasive species is also your beloved pet

When we think of the reasons why animal species go extinct, it’s usually invasive species like rats or snakes that come to mind. And climate change is never out of the picture.

However, in reality, a surprising animal makes this list – your friendly neighborhood house cat.

Cats may seem like sweet and harmless companions, but their impact on global ecosystems is far from good. Beneath their soft fur and playful demeanor lies one of nature’s most effective predators – stealthy, adaptable and ruthless.

Whenever you see a cat moving stealthily, it’s likely approaching a local critter for its next meal. With no particular favorites and an endless appetite, cats – both domestic and wild – have contributed to the extinction of one species after another to become one of the world’s most invasive predators.

From birds to mammals and everything in between, cats can be linked to 63 extinctions in modern times, according to a July 2016 study published in Proceedings of the National Academy of Sciences. Now, new research has shed more light on just how destructive this lovable little creature can be.

The cat’s diet includes over 2000 species

The average cat doesn’t discriminate, at least not when it comes to food.

A December 2023 study published in the journal Nature Communications cataloged 2084 species cut by cats. Of these, 347 species were classified as threatened, near threatened or extinct by the International Union for Conservation of Nature (IUCN).

In Australia alone, feral cats kill over 2 billion native animals each year, a number that has decimated populations of small marsupials, reptiles and ground-nesting birds.

In the United States, domestic and feral cats are responsible for the deaths of an estimated 2.4 billion birds and 12.3 billion small mammals each year.

Judging by the numbers, it’s clear that cats love to slice off wings and gnaw on the bones of birds more than any other taxonomic group on their hit list. Of the 2,084 species cut by cats, 981 were birds, followed by 463 reptiles.

Featured among the extinct cat-related species is the Stephens Island wren or Lyall’s wren (traversia lyalli)whose extinction was prompted by the arrival of a domestic cat named Tibbles. Other victims range from Hawaiian crows (Corvus hawaiiensis) to the New Zealand partridge (Coturnix novaezelandiae), both now extinct in the wild and native to the islands.

While plans to reintroduce the Hawaiian crow into the wild are underway, the cats’ ecological impact is clearly visible on the islands, where native species are particularly vulnerable. For example, in the Galapagos Islands, feral cats remain among the main threats to the critically endangered Galapagos gas (Pterodroma pheopygia).

Cats sit at the top of the island’s food chains

The ecological destruction caused by cats varies significantly between islands and continents.

On islands, where native species often evolved without large predators, cats can be destructive. Ground-nesting birds, slow-moving reptiles and small mammals are particularly vulnerable.

The lack of defensive behaviors among these species—combined with the cats’ exceptional hunting ability—has led to catastrophic population declines and even extinction.

Island ecosystems are inherently fragile, and the introduction of an apex predator like the cat upsets the delicate balance. In fact, island ecosystems harbor three times the number of conservation species associated with cats than continents.

On the mainland, the influence of cats is more nuanced.

While native species on larger lands have often coexisted with predators, cats still pose significant threats, especially in urban and suburban environments. Here, cats exploit fragmented habitats and thriving populations of small mammals and birds, further straining ecosystems already under pressure from human development.

Their presence can outcompete or eliminate native predators and disrupt food chains. However, the greater diversity of predators and competitors on the mainland often mitigates the level of destruction seen on the islands.

What makes cats such ruthless predators?

The invasive abilities of cats are derived from a combination of biological traits and human support, implemented to devastating effect.

• Cats reproduce at an astonishing rate. A single female cat can produce up to 180 kittens in her lifetime under optimal conditions. This exponential growth enables wild populations to establish and expand rapidly, especially in areas with abundant food and minimal predation.
• They have versatile hunting skills. This ensures that they are able to hunt a wide range of prey, from birds and rodents to reptiles and even insects. They are equipped with retractable claws, sharp teeth, acute night vision and exceptional hearing, making them skilled hunters both during the day and at night.
• Cats only need meat to keep going. It can come from any animal, as long as they have their fill. Over the years, evolution has helped cats to survive only on animal tissue and metabolic water derived only from a diet of fish or meat. This makes them opportunistic predators who will easily adapt their diet to thrive in any environment.
• Cats can also adapt their behavior. As solitary, territorial hunters, they use stealth and ambush tactics to defeat their prey. Their capacity for patience and persistence allows them to exploit even the most wary or elusive species.
• They rely on human support. Unlike other invasive predators, domestic cats receive direct and indirect support from humans. Many feral cats rely on food scraps, garbage, or intentional feeding by well-meaning individuals, which protects them from natural selection pressures such as starvation. Even well-fed domestic cats continue to hunt for sport, worsening their ecological impact.

Despite cats’ predatory nature, efforts are often made to prevent them from wreaking havoc without removing them from the ecosystem – such as the trap-neuter-return (TNR) method aimed at keeping feral cat populations under control. However, their wide range and ability to spread to new areas means that cats continue to influence every continent except Antarctica.

And while cats remain beloved companions for many people, their role as one of the world’s most destructive invasive species underscores the need for responsible stewardship. Balancing our love for these animals with the urgent need to protect vulnerable wildlife isn’t just a challenge—it’s an ecological imperative today.

While cats can be predators to a number of species around the world, we still share a powerful bond with our domestic cats. How attuned are you to your cat’s needs and behaviors? Find out now by taking this 2-minute Pet Personality Test.