California Department of Fish and Wildlife

Cats and Wildlife

Domestic Cats

The impacts of feral or free-ranging human companion or domestic animals poses a challenge for contemporary wildlife management. The domestic cat is the best known of these animals for its impacts to wildlife. Feral cats are an exotic species in the United States. With numbers in the millions, these animals are recognized as one of the most widespread and serious threats to the health and integrity of native wildlife populations and natural ecosystems. Feral cats present special challenges for wildlife managers because their negative impacts are poorly understood by the public. Feral cats and other exotic species have become accepted as part of the environment and considered "natural" by many people. Advocacy groups promote their continued presence and few policies and laws deal directly with their control.

The domestic cat (Felis catus) originates from an ancestral wild species, the European and African wild cat (Felis silvestris) and is now recognized as a separate species. The estimated number of pet cats in the United States has grown from 30 million in 1970 to over 70 million, however reliable estimates of the total cat population are impossible to determine. It is estimated that approximately 30 percent of all households have cats, and in rural areas; the estimate is around 60 percent.

The cumulative impact of domestic cats on wildlife is impossible to quantify, however the growing body of literature strongly indicates that domestic cats are a significant factor in the mortality of native small mammals, birds, reptiles, and amphibians. Because feral cats often receive food rom humans, they can reach population levels that create areas of abnormally high predation on wildlife. Even well fed cats have been documented to prey on wildlife regularly. When the prey is a threatened or endangered species, the result could lead to extirpation or extinction. Effects of cat predation are most significant in island settings (actual or isolated habitats), where prey populations are already low or stressed by other factors. These include natural areas where cat colonies are maintained. Competition with native predators, disease implications for wildlife populations, and pet owners' attitudes about wildlife and wildlife management are also important factors.

Even if conservative estimates of prey taken are considered, the numbers of animals killed is immense. Feeding cats does not stop them from killing or injuring wildlife and they frequently do not eat what they kill. The possibility for disease transmission among feral cats, wildlife, humans, and other pets should be a serious concern where feral cats are abundant. Cats were introduced into California and North America by humans who are now responsible for the control and removal of cats that prey on wildlife.

The Department considers the impact of feral cats on wildlife to be significant and an issue that must be better managed to protect California's' unique wildlife biodiversity.

Table of Contents

This is a compilation of online references selected to assist land and wildlife managers, and others, in understanding the effects of free-ranging domestic cats on wildlife. Also, it provides sources of information useful for planning and implementing effective wildlife management and protection measures.

Questions or comments to Kent Smith at the CDFW.