What is an invasive species?
An alien species is when an animal or plant has been taken by humans and introduced into an ecosystem where it is not naturally present. An alien species becomes classified as an invasive species when it can reproduce and proliferate in the ecosystem, causing negative changes.
This is different to a native species that naturally live and thrive in a particular ecosystem having evolved there over millions of years.
Invasive species are incredibly problematic and can quickly take over a habitat disrupting the natural functions and balance of that ecosystem. This can affect the useful services provided by the ecosystem such as pollinating crops, seed dispersal, oxygen and moisture production and water filtration to name a few. Sometimes an invasive species can become so numerous it is a public health or road safety hazard.
Learn more about invasive species.
Why are feral cats a problem in the Cayman Islands?
Cats are kept as domestic pets, however large numbers of unowned feral cats are present across all three islands in both urban and remote natural habitats. Cats have an innate instinct to hunt prey, whether intended as a food source or not. The Cayman Islands are small island ecosystems where there are no natural predators, so native wildlife did not evolve to have instincts against these cunning hunters. Many of Cayman’s native species are experiencing dramatic declines in population numbers as a result of being hunted by roaming cats.
Globally, roaming cats have contributed to the extinction of at least 33 species and continue to threaten other critically endangered species where they have been introduced, including in the Cayman Islands.
The Grand Cayman Blue Iguana and Sister Islands Rock Iguana are directly threatened with extinction by feral cats. Iguanas are vulnerable to predation within the first two years of life, and population data from surveys show young iguanas are becoming rarer to find, with too few iguanas making it to breeding age. Seabirds nesting in the Cayman Islands are also directly threatened with local extinction by feral cats. Sometimes an entire seabird family has been destroyed by cats, as the parents try to defend the flightless chicks.
Department of Environment reports on the impacts of feral cats and rats on native species
Download Analysis of trapping rates showing decline in numbers of feral cats in Little Cayman, 2022-2024
Download Formal study on the feasibility of eradicating feral cats from all of Little Cayman
Download A study of feral cat impacts on wildlife and assessment of strategies to control them
Download Report on feral cat and rat removal and the breeding success of Brown Boobies: Cayman Brac 2023
Download Results of population estimates of feral cats using wildlife cameras: Little Cayman 2022-2023
Download DoE rat monitoring report: Little Cayman 2023-2024
Download Full report on DoE’s Sister Isles Rock Iguana population surveys on Little Cayman up to 2023
Download Report on a feral cat control session conducted in January-February 2023
Download Report on the health status and diet of feral cats on Little Cayman
Download Full summary of green iguana population surveys on Grand Cayman up to 2023
Download A compilation of Cayman-specific evidence of the impacts of feral cats on wildlife (2019)
Download Report on an index of the feral cat population abundance using night surveys with flashlights: Little Cayman 2021-2023