The issue of feral and free-roaming domestic cats is an important and sometimes divisive topic among many animal care and wildlife professionals, including veterinarians, conservation organizations, and animal welfare groups. There are many reported negative effects of feral and free-roaming domestic cats, such as effects on wildlife populations and disease transmission to animals and people, in addition to humane concerns for the feline populations, and the cost and time commitment associated with management programs.
Feral and free-roaming domestic cats have been documented to affect wild populations of native reptiles, birds, and mammals through predation. In North America alone it is estimated that hundreds of millions, and possibly billions, of birds, reptiles, small mammals, and amphibians are killed or injured by feral cats each year. Even well-fed cats will hunt or injure wildlife. Feral cats have played a significant role in the extinction or population decline of several wild reptiles including iguanas (Brachylophus spp.) and skinks (Emoia spp.) in the Fiji Islands, iguanas (Cyclura spp.) on Caribbean islands, tuatara (Sphenodon punctatus) in New Zealand, and the giant lizard (Gomerana gomerana) in the Canary Islands.
Free-roaming cats suffer higher morbidity and mortality, with far shorter lifespans, than their indoor counterparts. Several zoonotic diseases, including rabies, toxoplasmosis, and hookworm can be carried and transmitted by free-roaming cats. In some cases these diseases and others carried by domestic cats have significant negative effects on both free-roaming and captive wildlife species.
Several management options exist for the control of feral and free-roaming cats, including permanent removal of free-roaming cats (via euthanizing, adoption, or maintaining in enclosed facilities), trap-neuterrelease, and trap-vasectomy-hysterectomy-release. There is significant debate over the efficacy and resources that each method requires to be effective at controlling and eliminating populations of feral cats. In all scenarios, significant resources and monitoring maintained over a protracted period of time are essential, and efforts are hindered by the recruitment of new cats into existing populations. Failure to spay and neuter pet cats, and abandonment of unwanted pets, present a massive challenge to any control program.
The Association of Reptilian and Amphibian Veterinarians (ARAV) understands that this is a complex and often emotionally charged issue for those who care about the welfare of both domestic cats and wildlife species. We support the following actions to help curb the negative effects of feral and free-roaming cats around the world:
- Encourage pet owners to keep owned cats indoors and spayed/neutered for the health of both the cats and the natural environment.
- Reduce the numbers of stray and feral cats through humane measures.
- Remove free-roaming and feral cats from conservation lands or ecologically sensitive areas.
- Promote education of the general public and animal care professionals regarding the detrimental effects that free-ranging and feral cats can have on local wildlife populations, including reptiles and amphibians.
References
Foley P., J. Foley, J. Levy et al. Analysis of the impact of trap-neuter-return programs on populations of feral cats. 2005. JAVMA 277: 1775-1781.
Gerhold R., D. Jessup. Zoonotic diseases associated with free-roaming cats. 2012. Zoonoses and Public Health.
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Loss S.R., T. Will, P. Mara. The impact of free-ranging domestic cats on wildlife in the United States. 2013. Nature Communications 4: 1396.
Loyd K.A.T., S.M.Hernandez, J.P.Carroll, K.J. Abernathy, and G.J.Marshall. Quantifying free-roaming domestic cat predation using animal-borne video cameras. 2013. Biol Conserv 160:183-189.
McCarthy R.J., S.H. Levine and J.M. Reed. Estimation of effectiveness of three methods of feral cat population control by use of a simulation model. 2013. JAVMA 43(4): 502-511.
Nogales M., Martín, A., Tershy, B. R., Donlan, C. J., Veitch, D., Puerta, N., Wood, B. And Alonso, J. A Review of Feral Cat Eradication on Islands. 2004. Conservation Biology 18: 310–319.
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