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Publication #WEC-136

Impacts of Free-ranging Pets on Wildlife1

Joe Schaefer2


Cats and dogs are domesticated predators. They have natural prey-chasing, capturing, and killing instincts. As a result of this and the large numbers of them in Florida, cats and dogs have the potential to severely impact local wildlife populations. In addition to reducing populations of species and limiting the number of prey items for native predators, free-ranging pets can cause other problems. For example, they serve as important reservoirs for human and wildlife diseases like ringworm, toxoplasmosis, leptospirosis, distemper, and rabies. They may be an important factor in introducing these diseases into susceptible wildlife populations.

Dogs kill turtles and other wildlife. My own Australian silky terrier killed a young blue jay and several frogs and lizards in my backyard. Exotic snakes and other pet predators can also have local impacts if released into the wild. But the pet that is by far the most devastating on wildlife populations is the furry feline. While a few species such as great horned owls and coyotes may think of cats as delicacies, many wildlife populations are threatened by "outside" cats that are allowed to range freely.

The instinctive hunting and killing behavior of cats is extensively documented. Unlike wild predators that kill to eat, cats kill impulsively even when they are not hungry. Animals that nest or feed on or close to the ground, such as cardinals, bobwhites, towhees, wrens, rabbits, and lizards, are most susceptible. At least part of the population declines experienced by Florida's endangered beach mice are due to domestic cat predation. A Michigan study provided some insight into the impact of a single cat on local prey. During an 18-month period, one well-fed, domestic farm cat killed at least 60 birds and 1,600 small mammals. A study in England estimated that over a million birds are killed each year there by free-ranging cats.

Although it is impossible to determine the extent of this problem in Florida, estimates are astounding. Several thousand stray cats are picked up by county animal control departments in Florida each month (for example, Orange County averages almost 670/month). If each cat killed only one animal each month, tens-of-thousands of animals would be killed each year here. This is a conservative estimate because studies have shown that cats kill more than one animal per month (almost 100 were killed each month by the cat in the Michigan study), and we really do not know what percentage of all free-ranging cats are picked up by animal control departments.


Dr. H.W. Kale II and David Maehr recommend actions in their book Florida's Birds that you can take to reduce the chances of cats' sneaking up undetected on wildlife on your property:

  • Do not place a bird feeder or bath immediately next to dense shrubbery or other cat hiding places.

  • If you own an outside cat, place two bells on its collar--some cats can learn to adjust their moves to silence a single bell.

  • Do not let your cat roam at night when they can be much more effective predators on sleeping prey.

  • If you are having problems with a neighbor's cat, speak to the neighbor about the problem and see what can be worked out.

  • Cats hate water, so you may be able to discourage a cat from entering your yard by spraying it several times with a garden hose.

  • If the cat is an untagged stray or feral, trap it with a live trap (the raccoon-type trap) then turn it over to the local animal control office or Humane Society.

The best solution to the problem of predatory cats and dogs is responsible pet ownership including spaying and neutering. as well as confining. Responsible pet owners are also concerned about the potential dangers that their free-ranging pets may encounter: death by vehicles; diseases transmitted by wildlife and other pets; death by wildlife predators; injury from fights with other dogs and cats; and the various animal control practices used by unhappy neighbors.

Suggested Reading

Kale, II, H.W. and D.S. Maehr. 1990. Florida's Birds. P. 250. Pineapple Press, Inc. Sarasota, FL 288 pp.



This document is WEC-136, one of a series of the Department of Wildlife Ecology and Conservation, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Publication: December 1991, as SS-WIS-52. Renumbered August 1999. Reviewed March 2013. Visit the EDIS website at


Joe Schaefer, Ph.D., professor and district Extension director for South Florida, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611.

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county's UF/IFAS Extension office.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.