One analysis documented more than 550 verified predation events drawn from images and videos posted by cat owners, many filmed in gardens, streets and urban parks. Photo credit: Klimek Pavol/Shutterstock
Domestic cats are among the most popular pets worldwide, yet a growing body of scientific evidence shows that cats allowed to roam outdoors pose a serious and often underestimated threat to wildlife. Images and videos shared on social media platforms such as TikTok, Instagram and YouTube are now helping researchers document this impact in unprecedented detail, particularly in urban environments where traditional wildlife monitoring is limited.
By analysing thousands of publicly shared posts, scientists have identified clear patterns of predation by domestic cats, capturing hunting behaviour that would otherwise go unrecorded. These findings confirm that cats continue to hunt even when well fed, driven by instinct rather than hunger, and that their impact extends far beyond birds to include reptiles, amphibians and invertebrates.
Social media as an unexpected research tool
New insights from online content
Recent peer-reviewed studies using social media imagery have revealed domestic cats preying on a wide range of species, including insects, lizards, frogs and small mammals. One analysis documented more than 550 verified predation events drawn from images and videos posted by cat owners, many filmed in gardens, streets and urban parks.
Researchers say this method complements traditional fieldwork by capturing interactions that are rarely recorded, particularly predation on invertebrates. The findings suggest the ecological footprint of domestic cats in cities has been significantly underestimated.
A global wildlife problem
Scale of predation and extinctions
Globally, domestic cats are recognised as one of the most damaging invasive predators. A comprehensive scientific review published in Nature Communications found that cats have preyed on more than 2,000 species worldwide, with at least 347 of those species classified as threatened or near threatened under international conservation criteria.
Crucially, conservation bodies estimate that free-ranging domestic and feral cats have contributed directly to the extinction of at least 63 vertebrate species, including birds, mammals and reptiles. These extinctions are not theoretical or historical abstractions: they are well documented, with cats identified as a primary or significant contributing factor in species losses recorded by the International Union for Conservation of Nature.
The impact is most severe on islands, where native wildlife evolved without mammalian predators. In such ecosystems, cats can rapidly devastate populations that lack defensive behaviours, pushing already vulnerable species beyond recovery.
Urban areas are not immune
Cities as active hunting grounds
Urban environments were once assumed to limit the ecological impact of cats, but research increasingly shows the opposite. High densities of domestic cats in towns and cities mean that even modest individual hunting rates can result in substantial cumulative losses of wildlife.
Studies in urban and suburban areas have documented cats killing birds, bats, reptiles and small mammals, including species already under pressure from habitat loss, pollution and climate change. Social media footage reinforces these findings, showing hunting behaviour in densely populated neighbourhoods where wildlife refuges are scarce.
Spain’s particular vulnerability
Endemic species under pressure
In Spain, the impact of domestic cats is a growing conservation concern, particularly in biodiversity-rich regions. Scientists highlight the Canary Islands as especially vulnerable due to their high number of endemic species, many of which exist nowhere else in the world and have no natural defences against introduced predators such as cats.
Research has recorded free-roaming cats within protected areas, including Natura 2000 sites, where they overlap with threatened bird and reptile populations. Conservationists warn that current legislation does not always clearly distinguish between owned, stray and feral cats, complicating effective management and wildlife protection efforts.
Summary of the scientific findings
- Domestic cats have preyed on over 2,000 wildlife species worldwide, including at least 347 threatened species
- Free-ranging cats have contributed to the extinction of at least 63 vertebrate species globally
- Social media analysis has revealed hundreds of previously undocumented predation events, particularly involving insects and reptiles
- Urban areas act as hotspots due to high cat densities and already stressed wildlife populations
- In Spain, regions such as the Canary Islands face heightened risk because of endemic species and cat presence in protected areas
- Scientists agree that keeping cats indoors is the most effective way to reduce wildlife harm
A growing conservation debate
Domestic cats remain cherished companions, but scientific evidence increasingly shows that allowing them to roam freely carries significant ecological costs. Social media has unintentionally become a powerful research tool, exposing interactions that were previously invisible to scientists and policymakers alike.
As urbanisation continues and biodiversity declines, researchers warn that balancing responsible pet ownership with wildlife protection will become an increasingly urgent challenge, both in Spain and globally.
