Cats are currently the most popular companion animal in the United States. According to the American Pet Products Association, there are approximately 86 million cats with homes, compared with 78 million dogs. Despite the fact there are 86 million cats with homes, there are many homeless cats in varying states of socialization with humans. These cats, often termed feral cats, are the same species as our companions – Felis catus.
Regardless of geographic location or community demographics, the free-roaming cat population in any area will be composed of cats from three general categories:
- Cats that previously had homes and are now lost and/or abandoned
- Cats that currently have homes but are allowed to roam
- True feral cats – the offspring of other free-roaming cats that are sexually intact; true feral cats are not accustomed to contact with humans and are typically too fearful of handling by humans
The relative proportion of each of these types of cats within a free-roaming population varies widely among different locations. It is important to point out the heterogeneity of a population. As a community approaches managing its ‘feral cats,’ it should take into consideration that some of the animals in the population are not truly feral, and will have some socialization history with humans. For this reason, some communities have started to apply the term "community cats" to this diverse population.
Just how many community cats are there in the United States? With their elusive behavior and incredibly dynamic population, it is impossible to accurately quantify, but some estimates suggest that the number of community cats rivals the number of cats with homes.
Population dynamics: One distinct characteristic of community cats is their tendency to band together in small groups called colonies. A colony occupies a specific territory, and the population typically reaches a carrying capacity based on available resources – food, water, and shelter. People are an important source of these resources. People may intentionally provide food which can lead to different levels of attachment and responsibility with the cats. However, intentional feeding represents a negligible proportion of the provision of resources when one considers the ubiquitous waste products of human civilizations. Resources for free-roaming cats are woven into our communities through garbage dumpsters and landfills. Parks and woodlands also provide resources for cats.
This inextricable aspect of the cat-human relationship is emphasized because it sets the stage to explain why removal of community cats is not an effective means of population control. Removal can mean any number of things, but it usually involves an eradication approach, such as trapping and euthanasia. Eradication has proven ineffective for two main reasons. First, it is nearly impossible to remove all of the cats. Any number of cats can elude the trappers, and survivors quite efficiently repopulate the area. There is also the phenomenon known as the “vacuum effect,” in which cats from nearby areas move into the vacuum left by the cats that were removed. The new cats reproduce to achieve carrying capacity. This creates a vicious cycle of trapping and euthanasia.
Eradication is a short-term solution for any location unless the resources that attracted the cats in the first place are also removed. Removing such resources is not an easy task. People who feel attachment to the cats will resist feeding bans. Moreover, removing the inherent resources of a community - garbage dumpsters, landfills, city parks, etc. - is not realistic. Because eradication is ineffective for long-term population control, the recommended approach to community cat management instead aims to reduce reproductive capacity of the animals.
Trap-neuter-return: The Trap-neuter-return (TNR) approach is one that many communities have embraced. In its most basic form, this approach involves trapping and sterilizing the cats, vaccinating them against rabies, identifying them with an ear-tip, and returning them to their original colony. Returning sterilized cats to their original colony stabilizes population growth by preventing new litters within the colony, as well as reducing the number of new cats moving into the colony to take advantage of its resources. The success of a TNR program is highly dependent on follow-up management, to monitor health of the existing population and to ensure sterilization of new cats that might move into the colony. The goal of any TNR program is gradual population reduction over time through attrition. Numerous studies have shown that TNR is an effective and humane method of controlling and reducing the population of free-roaming cats.
The TNR approach is not without its controversy, and there is ongoing dialogue about issues such as the impact of colonies on wildlife, whether TNR enables abandonment of cats by the public, and the legality of returning cats to a free-roaming environment. While such concerns exist, it can be noted that both opponents and advocates of TNR share the common goal of fewer free-roaming cats. The concept of TNR as a humane method for cat population control is endorsed by the following veterinary professional and animal welfare organizations, as well as countless humane groups throughout the country:
- Alley Cat Allies
- American Association of Feline Practitioners
- American Animal Hospital Association
- American Humane Association
- American Society for the Prevention of Cruelty to Animals
- Association of Shelter Veterinarians
- Cat Fanciers’ Association
- Humane Society of the United States
- National Animal Control Association
References
- Hughes, K.L., Slater, M.R., Haller, L., 2002. The effects of implementing a feral cat spay/neuter program in a Florida county animal control service. Journal of Applied Animal Welfare Science 5: 285-298.
- Levy JK, Gale DW, Gale LA. 2003. Evaluation of the effect of a long-term trap-neuter-return and adoption program on a free-roaming cat population. Journal of the American Veterinary Medical Association 222:42-46.
- Centonze L.A., Levy J.K. 2002. Characteristics of free-roaming cats and their caretakers. Journal of the American Veterinary Medical Association 220: 1627-1633.
- Natoli E, Maragliano L, Cariola G, Faini A, Bonanni R, Cafazzo S, Fantini C. 2006. Management of feral domestic cats in the urban environment of Rome (Italy). Preventive Veterinary Medicine 77:180-5.
Amy Fischer, Ph.D - University of Illinois
