Cat predation on wildlife

[2] A 2013 systematic review in Nature Communications of data from 17 studies found that feral and domestic cats are estimated to kill billions of birds in the United States every year.

[8] The large animal population of the remote Kerguelen Islands in the Southern Indian Ocean comprises introduced species, including cats, rabbits, some seabirds, and sheep .

Fish and Wildlife Service identified free-ranging domestic cats as the leading human-caused threat to birds and small mammals in the United States.

[6][18] These figures were much higher than previous estimates for the U.S.[6] Unspecified species of birds native to the U.S. and mammals including mice, shrews, voles, squirrels and rabbits were considered most likely to be preyed upon by cats.

[20]: 399  Other studies caution that removing domestic cats from islands can have unintended ecological consequences, including surges in rat populations, which may further endanger native bird[21] and mammal species.

[22][23] Cats are sometimes intentionally released into urban environments on the popular assumption that they will control the rat population; but there is little scientific basis for this.

The reality is that cats find rats to be large and formidable prey, and so they preferentially hunt defenseless wildlife such as lizards and songbirds instead.

In many cases, it is easier to eradicate cats from islands than from mainland areas, which allows studies on the effects of the removal on native prey species.

In the Caribbean, cats have significantly impacted reptiles such as iguanas, destabilizing population dynamics and interrupting essential ecosystem functions like herbivory and seed dispersal.

[32] Numerous Australian environmentalists claim the feral cat has been an ecological disaster in Australia, inhabiting most ecosystems except dense rainforest, and being implicated in the extinction of several marsupial and placental mammal species.

[38] The authors recommended policies be implemented, such as a public education initiative to encourage people to keep their cats indoors, and building more animal shelters.

Cats on the urban edge of the city of Cape Town kill more than 200,000 animals in the Table Mountain National Park annually.

[44] Nick Forde, a trustee of the UK charity SongBird Survival, said the RSPB's claim of no evidence was disingenuous because adequate studies had not been done.

[6] In California, a study found that in areas where humans feed feral cats, they will continue to hunt large numbers of native birds even without the intention of eating them.

The critically endangered palila produces few eggs per year and the nestlings develop slowly, so that depredation rate could result in extinction.

The presence of cats altered the prey foraging, movement, and stress response and significantly impacted survival and reproduction.

171  Systemic infection, usually caused by Pasteurella multocida, a highly pathogenic bacterial species that's found naturally in cat mouths, can kill small animals in as little as 15 hours.[56]: p.

171  Additionally, the study revealed that even when wildlife survive the immediate effects of a cat attack, they often left weakened and vulnerable to secondary threats, such as predation or disease.

A secondary effect of cat predation on wildlife is the ability to transmit a range of diseases mediated by or acquired from prey to other animals.

Toxoplasmosis is caused by the single-celled coccidian parasite Toxoplasma gondii that only reproduces in cats but is capable of affecting all warm-blooded animals.

[63] Its reproduction mechanism requires cats, the definitive hosts, to prey on the animals that had ingested material contaminated with feline feces.

[72] Tularemia, also known as "rabbit fever" caused by the bacterium Francisella tularensis, is a zoonotic disease that can affect various species, including cats.

Cats typically contract tularemia through interactions with infected wildlife, including prey such as rabbits and rodents, or via vectors like ticks and insect bites.

The Newhaven Wildlife Sanctuary in Central Australia is spearheading a major biodiversity project by establishing a 650-square-Kilometer feral cat-free zone.

This initiative involves constructing a 1,600-kilometer predator-proof fence and eradicating feral cats within the sanctuary to create a safe environment for reintroducing endangered species.

[81] Feral cats pose a severe threat to Australian Wildlife, not only by preying on native animals but also by spreading diseases.

Introduced during European settlement in the 1800s to control rodents and rabbits, feral cats quickly adapted to Australia's environment, thriving on abundant prey and surviving with minimal water.

[82] A study found that providing domestic cats with high meat content diets and engaging them in object play significantly reduced their predation on wildlife.

Cats fed a meat-rich diet reduced their hunting activity by 36%, while daily play sessions decreased prey capture by 25%.

These findings suggest that improving cats' diets and offering alternative outlets for their hunting instincts can effectively mitigate their impact on wildlife.

Cats kill billions of wild birds each year. This feral cat near Brisbane has caught a Pale-headed rosella .
Lyall's wren became extinct within two years of the introduction of cats to Stephens Island .
A feral cat with an American Robin . Plate from Forbush (1916).
Selection of causes of bird deaths in the United States
Mouse partially eaten by a house cat
Ancient Egyptian cat statuette intended to contain a mummified cat 332–30 B.C.
1. The only known definitive hosts for Toxoplasma gondii are members of family Felidae (domestic cats and their relatives). Unsporulated oocysts are shed in the cat's feces. Although oocysts are usually only shed for 1–3 weeks, large numbers may be shed. Oocysts take 1–5 days to sporulate in the environment and become infective. 2. Intermediate hosts in nature (any warm-blooded animals, such as birds and rodents) become infected after ingesting soil, water or plant material contaminated with oocysts. 3. Oocysts transform into tachyzoites shortly after ingestion. These tachyzoites localize in neural and muscle tissue and develop into tissue cyst bradyzoites. 4. Cats become infected after consuming intermediate hosts harboring tissue cysts. Cats may also become infected directly by ingestion of sporulated oocysts. 5. Animals bred for human consumption and wild game may also become infected with tissue cysts after ingestion of sporulated oocysts in the environment. Humans can become infected by any of several routes: 6. Eating undercooked meat of animals harboring tissue cysts. 7. Consuming food or water contaminated with cat feces or by contaminated environmental samples (such as fecal-contaminated soil or changing the litter box of a pet cat). 8. Blood transfusion or organ transplantation. 9. Transplacentally from mother to fetus. In the human host, the parasites form tissue cysts, most commonly in skeletal muscle, myocardium, brain, and eyes; these cysts may remain throughout the life of the host. 10. Diagnosis is usually achieved by serology, although tissue cysts may be observed in stained biopsy specimens. 11. Diagnosis of congenital infections can be achieved by detecting T. gondii DNA in amniotic fluid using molecular methods such as PCR.
Toxoplasma lifecycle
Tularemia lesion in human
Sterilized cat with a tipped ear