Office of Law Enforcement
Pacific Region/Pacific Southwest Region




October 2009

Cats Gone Wild!

Cat Under Car
A feral cat sitting under an abandoned car. Photo by Paul Chang, U.S. Fish and Wildlife Service.

When most people think of cats, they picture a domestic house cat: a cat that’s comfortable around people and spends a good amount of time indoors, perhaps napping by the fire or on someone’s lap.  However, this scene is less and less the case anymore.  To understand cats today we have to look back to how they came to be such a big part of our lives.

Cats are a domesticated animal.  This means that cats were adapted from a wild animal and tamed to have close contact with humans and also for the benefit of humans.

Over the past several hundred years, the “domestic cat,” which was once honored by ancient civilizations for its ability to kill rodents, has changed and adapted with the times.  Domestic cats today can be classified into four different categories based on their way of life.

  • House Cats – House cats spend more time indoors than out, depend on their owners for food, are comfortable around people and may sometimes kill wildlife out of instinct.
  • Outdoor Cats – Outdoor cats spend most of their time outside but have a home to go to for food and shelter, they are comfortable around people and may sometimes kill wildlife out of instinct.
  • Stray Cats – Stray cats were either indoor or outdoor cats at one point but their owners abandoned them and now they roam free, feeding where they can on either wildlife or food left out by strangers. Depending on how long they have been stray, they may or may not feel comfortable around people and may still kill wildlife out of instinct – even if a stranger is leaving food out for them.
  • Feral Cats – Feral cats are born to stray cats or other feral cats.  They have no owners or home and never did.  These cats feed on wildlife or on food left out by strangers.  Since these cats never lived with or interacted with people, it is very difficult for them to be adopted into a home.  Feral cats are social and usually live in loose colonies.

Watch the Video

This video depicts the dangers feral cats pose to wildlife. Video by U.S. Geological Survey

While domestic cats were formerly valued for their ability to control mice, rats and other pests, few cats are kept for that purpose today.  Our way of life has changed, but the predatory instincts of cats have not. If all cats were house cats, this would probably not be an issue; however the presence of stray and feral cats changes things.  For more information on the benefits of keeping your cat indoors, click here.

Domestic cats have the ability to live in almost any environment and are prevalent around the world.  Cats prey upon small animals.   Some of the small animals that cats prey upon are rare and in danger of extinction.  Many are federally protected, endangered or threatened birds that add much to the biodiversity of our planet.

What’s more, domestic cats have few “natural” predators, such as larger wild cat species like bobcats and cougars.  Since domestic cats are mostly city dwellers,  where wild cats are rarely found and where domestic cats rarely attack each other leading to a kill, there is little natural population control.

One solution some people feel will help this problem is a program called Trap Neuter Return (TNR).  In the program, individuals capture stray or feral cats, take them to a veterinarian, have them neutered, and then return them back to where the cat was found.  It was thought that this would help curb the population so that there would be fewer feral cats killing birds and other wildlife.  However, after many years of these programs and subsequent studies to determine their success, most cat populations stayed the same, increased or decreased only slightly.  There was no “success” story.

Fledging Hawaiian Petrel outside burrow

Feral cat at entrance of Hawaiian Petrel burrow

Feral Cat entering endangered Hawaiian Petrel burrow with chick inside

Feral cat eating part of an Endangered Hawaiian Petrel
Photo series by Fern Duvall, Hawaii Division of Forestry and WIldlife (DOFAW) Click on each thumbnail to view larger image.

Furthermore, this solution does not speak directly to the problem of feral cats killing wildlife.  Neutering cats does not take away their instinct to kill.  Therefore, even if TNR were to have success by controlling feral cat populations, it would have no immediate effect on the problem of our nation’s wildlife being killed.  For more information on domestic cats’ ability to kill birds and other wildlife, click here.

The worst case scenario for this problem is on an island that is home to rare bird species and where wild cats have never been a natural inhabitant.  For example, the Hawaiian Islands have an amazing amount of biodiversity, yet lack the typical broad spectrum of mammal predators.  In the State of the Birds Report (.pdf 4.34MB) released in March of 2009 by Secretary of the Interior Ken Salazar, one key finding was that the Hawaiian Islands are:

“Threatened by habitat destruction, invasive species and disease, nearly all native Hawaiian bird species are in danger of extinction if urgent conservation measures are not implemented immediately.  Since humans colonized the islands in 300 AD, 71 Hawaiian bird species have gone extinct; 10 others have not been seen in as long as 40 years.”

Cat at Nesting Site in Hawaii
Photo taken with a remote camera at an artificial burrow of federally threatened Newell's shearwaters on Kilauea Point National Wildlife Refuge in Kauai, HI. Photo by U.S. Fish and Wildlife Service.

Feral cats are contributing to this problem by killing native Hawaiian birds, including burrow-nesting seabirds.  The impacts of introduced predators like cats are especially severe on islands, where neither the prey species (birds) nor the predators (cats) can readily disperse to new areas.  Under such conditions, even low numbers of predators can cause great destruction of prey populations.

The issue of feral cats evokes incredibly strong feelings from individuals.  Many people who hear about feral cats immediately feel a strong pull to one side or the other.  But no matter what an individual’s personal views are on the subject, we cannot ignore the importance of healthy native wildlife populations in natural habitats.

Be aware that stray and feral cats pose some health and safety risks to both humans and wildlife.  The list below shows the diseases that can be contracted by humans or wildlife from exposure to a feral cat.  The links, from Center for Disease Control and Prevention and Cornell University College of Veterinary Medicine, provide information about these diseases.

Diseases Humans and Wildlife Can Get from Cats:

Diseases that can be transmitted from cats to humans

Diseases that can be transmitted from cats to other cats and wildlife

Diseases that can be transmitted from ectoparasites living on or in cats to humans or other wildlife:

Endangered Bird Parts from Cat Den
This picture depicts the stomach contents of a feral cat found dead on the Kilauea Point National Wildlife Refuge in Kauai, HI. There were two wedge-tailed shearwater chicks in the cat’s stomach.  If you look closely, you can see feet, wings, and heads. Photo by Brenda Zaun, U.S. Fish and Wildlife Service.

For more information or to contact the U.S. Fish and Wildlife Service, please go to and click on the “contact us” link at the top of the page.

Last updated: June 9, 2011

Law Enforcement Home
National Office of Law Enforcement Home Page
Pacific Southwest Region Home
Pacific Region Home

U.S. Fish and Wildlife Service Home Page | Department of the Interior  |  | About the U.S. Fish and Wildlife Service  | Accessibility  | Privacy  | Notices  | Disclaimer  | FOIA