Cats Threaten Global Ecosystems as Invasive Predators Driving Extinctions and Disrupting Fragile Wildlife Populations

Cats, typically seen as affectionate household companions are, in fact, one of the world’s most destructive invasive species. While invasive species like rats and climate change are often blamed for species extinctions, the domestic cat’s role in this crisis is frequently overlooked.

Cats are highly effective predators, stealthy, adaptable, and relentless. They hunt a wide variety of prey and have contributed significantly to the extinction of numerous species across the globe, including both domestic and feral cats.

Research shows that cats have been responsible for the extinction of at least 63 species, with more evidence linking them to the death of 2,084 species globally. In particular, cats prey on birds, mammals, and reptiles, with the most recent study revealing that 347 of the species hunted by cats are listed as threatened or extinct.

In Australia, feral cats kill over 2 billion native animals annually, severely impacting small marsupials, reptiles, and ground-nesting birds. Similarly, in the United States, domestic and feral cats are responsible for the deaths of billions of birds and mammals each year.

The devastation caused by cats is especially significant on islands, where native species evolved without major predators. Cats, as apex predators, have disrupted the delicate balance of island ecosystems, leading to sharp declines in native populations.

The Stephens Island wren, Hawaiian crow, and New Zealand quail are just a few of the species that have been driven to extinction due to predation by cats. Island ecosystems are particularly vulnerable to such disruptions, with cats being linked to three times the number of species of conservation concern compared to mainland environments.

On mainland areas, cats still pose serious threats, particularly in urban and suburban environments. While native species may have evolved alongside other predators, cats are able to exploit fragmented habitats, often decimating small mammal and bird populations.

Their presence can also lead to competition with native predators, further destabilizing food chains. Despite the greater diversity of predators on continents, cats remain highly effective in these environments, contributing to ecological imbalance.

Cats are such successful predators due to a combination of their biological traits and human support. Their rapid reproduction, hunting versatility, and ability to adapt to various environments make them formidable. Additionally, their reliance on human support, either through food scraps or deliberate feeding, buffers them from natural selection pressures and exacerbates their ecological impact.

Efforts like trap-neuter-return (TNR) aim to manage feral cat populations, but their widespread presence and ability to spread mean they continue to influence ecosystems worldwide. Balancing the affection people have for cats with the need to protect vulnerable wildlife is a critical ecological challenge.