Editing Cat (section)

== Ecology ==

=== Habitats ===
The domestic cat is a cosmopolitan species and occurs across much of the world. It is adaptable and now present on all continents except Antarctica, and on 118 of the 131 main groups of islands, even on the isolated Kerguelen Islands. Due to its ability to thrive in almost any terrestrial habitat, it is among the world's most invasive species. It lives on small islands with no human inhabitants. Feral cats can live in forests, grasslands, tundra, coastal areas, agricultural land, scrublands, urban areas, and wetlands.

The unwantedness that leads to the domestic cat being treated as an invasive species is twofold. As it is little altered from the wildcat, it can readily interbreed with the wildcat. This hybridization poses a danger to the genetic distinctiveness of some wildcat populations, particularly in Scotland and Hungary, possibly also the Iberian Peninsula, and where protected natural areas are close to human-dominated landscapes, such as Kruger National Park in South Africa. However, its introduction to places where no native felines are present also contributes to the decline of native species.

=== Ferality ===
Main article: Feral cat

Feral cats are domestic cats that were born in or have reverted to a wild state. They are unfamiliar with and wary of humans and roam freely in urban and rural areas. The numbers of feral cats is not known, but estimates of the United States feral population range from 25 to 60 million. Feral cats may live alone, but most are found in large colonies, which occupy a specific territory and are usually associated with a source of food. Famous feral cat colonies are found in Rome around the Colosseum and Forum Romanum, with cats at some of these sites being fed and given medical attention by volunteers.

Public attitudes toward feral cats vary widely, from seeing them as free-ranging pets to regarding them as vermin.

=== Impact on wildlife ===
Main article: Cat predation on wildlife

On islands, birds can contribute as much as 60% of a cat's diet. In nearly all cases, the cat cannot be identified as the sole cause for reducing the numbers of island birds, and in some instances, eradication of cats has caused a "mesopredator release" effect; where the suppression of top carnivores creates an abundance of smaller predators that cause a severe decline in their shared prey. Domestic cats are a contributing factor to the decline of many species, a factor that has ultimately led, in some cases, to extinction. The South Island piopio, Chatham rail, and the New Zealand merganser are a few from a long list, with the most extreme case being the flightless Lyall's wren, which was driven to extinction only a few years after its discovery. One feral cat in New Zealand killed 102 New Zealand lesser short-tailed bats in seven days. In the United States, feral and free-ranging domestic cats kill an estimated 6.3–22.3 billion mammals annually.

In Australia, one study found feral cats to kill 466 million reptiles per year. More than 258 reptile species were identified as being predated by cats. Cats have contributed to the extinction of the Navassa curly-tailed lizard and ''Chioninia coctei.''