A
feral cat is a descendant of a domesticated
catThe cat , also known as the domestic cat or housecat to distinguish it from other felids and felines, is a small, usually furry, domesticated, carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests...
that has returned to the wild. It is distinguished from a stray cat, which is a pet cat that has been lost or abandoned, while feral cats are born in the wild; the offspring of a stray cat can be considered feral if born in the wild.
In many parts of the world, feral cats are descendants of domestic cats that were left behind by travelers. Because cats are not native to all parts of the world, feral cats can cause harm to local environments by
preyingIn ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...
on local species. This is especially true on
islandAn island or isle is any piece of sub-continental land that is surrounded by water. Very small islands such as emergent land features on atolls can be called islets, cays or keys. An island in a river or lake may be called an eyot , or holm...
s where feral cats have sometimes had a substantial and deleterious effect on the local fauna.
Feral versus stray
The term "feral" is sometimes used to refer to an animal that does not appear friendly when approached by humans, but the term can apply to any domesticated animal without human contact. Hissing and growling are self-defense behaviors, which, over time, may change as the animal (whether "feral" or "stray") begins to trust humans that provide food, water, and care.
Feral cats that are born and living outdoors, without any human contact or care, have been shown to be adoptable and can be tamed by humans, provided they are removed from a wild environment before truly feral behaviors are established.
Life span and survival
The lifespan of feral cats is hard to determine accurately, although one study reported a
medianIn probability theory and statistics, a median is described as the numerical value separating the higher half of a sample, a population, or a probability distribution, from the lower half. The median of a finite list of numbers can be found by arranging all the observations from lowest value to...
age of 4.7 years, with a range between 0 to 8.3 years, while another paper referenced a mean life span of 2 – 8 years. For contrast, in captivity, an average life expectancy for male indoor cats at birth is 12 to 14 years, with females usually living a year or two longer.
History
During the
Age of DiscoveryThe Age of Discovery, also known as the Age of Exploration and the Great Navigations , was a period in history starting in the early 15th century and continuing into the early 17th century during which Europeans engaged in intensive exploration of the world, establishing direct contacts with...
, ships released rabbits onto islands to provide a future food source for other travelers. They eventually multiplied out of control and cats were introduced to keep their numbers, and that of mice and rats, down. The cats tended to favor local species as they were ecologically naive and easier to hunt. Their numbers too increased dramatically and soon they colonised many areas and were seen as pests too.
Historical records date the arrival of feral cats in Australia at around 1824. Despite that, it has been suggested that feral cats have been present in
AustraliaAustralia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
since before
EuropeanThe ethnic groups in Europe are the various ethnic groups that reside in the nations of Europe. European ethnology is the field of anthropology focusing on Europe....
settlement, and may have arrived with
DutchThe Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...
shipwreckA shipwreck is what remains of a ship that has wrecked, either sunk or beached. Whatever the cause, a sunken ship or a wrecked ship is a physical example of the event: this explains why the two concepts are often overlapping in English....
s in the 17th century, or even before that, arriving from present-day
IndonesiaIndonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...
with
MacassanMacassan or more correctly Makassar trepangers from the southwest corner of Sulawesi visited the coast of northern Australia for hundreds of years to process trepang : a marine invertebrate prized for its culinary and medicinal values in Chinese markets.These visits have left their mark on the...
fisherman and
trepangTrepanging is the Anglicisation of the act of collection or harvesting of sea cucumbers, known in Indonesian, as "trepang".The collector or fisher of trepang is coined a trepanger....
ers who frequented Australia's shores.
Diet and predators
Feral cats in Australia prey on a variety of wildlife. In arid and semi-arid environments, they eat mostly
introducedAn introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
European rabbitThe European Rabbit or Common Rabbit is a species of rabbit native to south west Europe and north west Africa . It has been widely introduced elsewhere often with devastating effects on local biodiversity...
s and
house miceThe house mouse is a small rodent, a mouse, one of the most numerous species of the genus Mus.As a wild animal the house mouse mainly lives associated with humans, causing damage to crops and stored food....
; in forests and urbanised areas, they eat mostly native
marsupialMarsupials are an infraclass of mammals, characterized by giving birth to relatively undeveloped young. Close to 70% of the 334 extant species occur in Australia, New Guinea, and nearby islands, with the remaining 100 found in the Americas, primarily in South America, but with thirteen in Central...
prey (based on 22 studies summarised in Dickman 1996). In arid environments where rabbits do not occur, native rodents are taken. Birds and reptiles form a smaller part of the diet.
Feral cats may be
apex predatorApex predators are predators that have no predators of their own, residing at the top of their food chain. Zoologists define predation as the killing and consumption of another organism...
s in some local ecosystems. In others, they may be preyed on by
feral dogsThe domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...
,
dingoesThe Australian Dingo or Warrigal is a free-roaming wild dog unique to the continent of Australia, mainly found in the outback. Its original ancestors are thought to have arrived with humans from southeast Asia thousands of years ago, when dogs were still relatively undomesticated and closer to...
,
coyoteThe coyote , also known as the American jackal or the prairie wolf, is a species of canine found throughout North and Central America, ranging from Panama in the south, north through Mexico, the United States and Canada...
s, wolves,
bearBears are mammals of the family Ursidae. Bears are classified as caniforms, or doglike carnivorans, with the pinnipeds being their closest living relatives. Although there are only eight living species of bear, they are widespread, appearing in a wide variety of habitats throughout the Northern...
s, cougars,
leopardThe leopard , Panthera pardus, is a member of the Felidae family and the smallest of the four "big cats" in the genus Panthera, the other three being the tiger, lion, and jaguar. The leopard was once distributed across eastern and southern Asia and Africa, from Siberia to South Africa, but its...
s,
bobcatThe bobcat is a North American mammal of the cat family Felidae, appearing during the Irvingtonian stage of around 1.8 million years ago . With twelve recognized subspecies, it ranges from southern Canada to northern Mexico, including most of the continental United States...
s,
lynxA lynx is any of the four Lynx genus species of medium-sized wildcats. The name "lynx" originated in Middle English via Latin from Greek word "λύγξ", derived from the Indo-European root "*leuk-", meaning "light, brightness", in reference to the luminescence of its reflective eyes...
,
hyenaHyenas or Hyaenas are the animals of the family Hyaenidae of suborder feliforms of the Carnivora. It is the fourth smallest biological family in the Carnivora , and one of the smallest in the mammalia...
s,
fisherThe fisher is a medium-size mammal native to North America. It is a member of the mustelid family, commonly referred to as the weasel family. The fisher is closely related to but larger than the American Marten...
s, crocodilians,
snakeSnakes are elongate, legless, carnivorous reptiles of the suborder Serpentes that can be distinguished from legless lizards by their lack of eyelids and external ears. Like all squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales...
s,
foxFox is a common name for many species of omnivorous mammals belonging to the Canidae family. Foxes are small to medium-sized canids , characterized by possessing a long narrow snout, and a bushy tail .Members of about 37 species are referred to as foxes, of which only 12 species actually belong to...
es and birds of prey.
Effects on wildlife
The impact of domestic cats on wildlife is a century old debate. In a 1916 report for the Massachusetts State Board of Agriculture titled
The Domestic Cat: Bird Killer, Mouser and Destroyer of Wildlife, noted ornithologist
Edward Howe ForbushEdward Howe Forbush was a noted Massachusetts ornithologist and a prolific writer, best known for his book Birds of New England....
stated in the preface:
Questions regarding the value or inutility of the domestic cat, and problems connected with limiting its more or less unwelcome outdoor activities, are causing much dissension. The discussion has reached an acute stage. Medical men, game protectors and bird lovers call on legislators to enact restrictive laws. Then ardent cat lovers rouse themselves for combat. In the excitement of partisanship many loose and ill-considered statements are made.
The report cited
Extinct BirdsExtinct Birds is a book by Walter Rothschild which covers globally extinct and rare birds as well...
, published in 1905 by zoologist
Walter RothschildLionel Walter Rothschild, 2nd Baron Rothschild, Baron de Rothschild FRS , a scion of the Rothschild family, was a British banker, politician, and zoologist.-Biography:...
, who stated, "man and his satellites, cats, rats, dogs, and pigs are the worst and in fact the only important agents of destruction of the native avifaunas wherever they go." Rothschild gave several examples of cats causing the extermination of some bird species on islands.
Some farmers and gamekeepers see feral cats as vermin. Feral cats catch and eat ground nesting birds such as pheasants and partridge. To protect their birds, some gamekeepers set traps and shoot feral cats as part of pest control..
Australia
Feral cats in Australia have caused the decline and extinction of animals on islands as they have been shown to cause a significant impact on ground birds and small native mammals. Feral cats have also stopped any attempts to re-introduce threatened species back into areas where they have become extinct as the cats have simply hunted and killed the newly released animals. Numerous Australian environmentalists claim the feral cat has been an ecological disaster in Australia, inhabiting most ecosystems except dense
rainforestRainforests are forests characterized by high rainfall, with definitions based on a minimum normal annual rainfall of 1750-2000 mm...
, and being implicated in the
extinctionIn biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
of several
marsupialMarsupials are an infraclass of mammals, characterized by giving birth to relatively undeveloped young. Close to 70% of the 334 extant species occur in Australia, New Guinea, and nearby islands, with the remaining 100 found in the Americas, primarily in South America, but with thirteen in Central...
and placental mammal
speciesIn biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
. Although a researcher disagrees with this view (Abbot 2002). Some others believe that there is little sound evidence that feral cats significantly affect native wildlife throughout the mainland and that it is only on the islands that they are a threat (Jones 1989; Wilson et al. 1992). Difficulties in separating the effects of cats from that of
foxFox is a common name for many species of omnivorous mammals belonging to the Canidae family. Foxes are small to medium-sized canids , characterized by possessing a long narrow snout, and a bushy tail .Members of about 37 species are referred to as foxes, of which only 12 species actually belong to...
es (also introduced) and environmental effects have hindered research into this. Cats have co-existed with all mammal species in Tasmania for nearly 200 years. The Western Shield program in Western Australia, involving broad-scale poisoning of foxes, has resulted in rapid recoveries of many species of native mammals in spite of the presence of feral cats throughout the baited area. In 2005, however, a study was published which for the first time found proof of feral cats causing declines in native mammals. An
experimentAn experiment is a methodical procedure carried out with the goal of verifying, falsifying, or establishing the validity of a hypothesis. Experiments vary greatly in their goal and scale, but always rely on repeatable procedure and logical analysis of the results...
conducted in Heirisson Prong (Western Australia) compared small mammal populations in areas cleared of both foxes and cats, of foxes only, and a control plot. Researchers found mammal populations were lower in areas cleared of foxes only and in the control plots.
Cats may also play a further role in Australia's human altered ecosystems; with foxes they may be controlling introduced
rabbitRabbits are small mammals in the family Leporidae of the order Lagomorpha, found in several parts of the world...
s, particularly in arid areas, which themselves cause ecological damage. Cats are believed to have been a factor in the extinction of the only mainland
birdBirds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
species to be lost since European settlement, the
paradise parrotThe Paradise Parrot was a colourful medium-sized parrot native to the grassy woodlands of the Queensland - New South Wales border area of northeastern Australia. Once moderately common within its fairly restricted range, the last live bird was seen in 1927...
.
Australian folklore holds that some feral cats in Australia have grown so large as to cause inexperienced observers to claim sightings of other species such as puma etc. This folklore is being shown to be more fact than fiction, with the recent shooting of an enormous feline, in the
GippslandGippsland is a large rural region in Victoria, Australia. It begins immediately east of the suburbs of Melbourne and stretches to the New South Wales border, lying between the Great Dividing Range to the north and Bass Strait to the south...
area of
VictoriaVictoria is the second most populous state in Australia. Geographically the smallest mainland state, Victoria is bordered by New South Wales, South Australia, and Tasmania on Boundary Islet to the north, west and south respectively....
. Subsequent DNA test showed the feline to be
Felis silvestris catus. Subsequent news of large feral cat sightings appear almost monthly in Australia, and the evidence is very good to suggest a breeding population of these enormous felines in the south-eastern states Victoria and
New South WalesNew South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...
.
New Zealand
The fauna of
New ZealandNew Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
has evolved in isolation for millions of years without the presence of mammals (apart from a few bat species). Consequently, birds dominated the niches occupied by mammals and many became flightless. The introduction of mammals after settlement by Māori from about the 12th century had a huge effect on the indigenous
biodiversityBiodiversity is the degree of variation of life forms within a given ecosystem, biome, or an entire planet. Biodiversity is a measure of the health of ecosystems. Biodiversity is in part a function of climate. In terrestrial habitats, tropical regions are typically rich whereas polar regions...
.
EuropeEurope is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
an explorers and settlers brought cats on their ships and the presence of feral cats were recorded from the latter decades of the 19th century.
It is estimated that feral cats have been responsible for the extinction of six endemic bird species and over 70 localised
subspecies as well as depleting bird and lizard species.
Consequences of introduction
Many islands host
ecologically naiveIsland tameness is the tendency of many populations and species of animals living on isolated islands to lose their wariness of potential predators, particularly of large animals. The term is partly synonymous with ecological naïvete, which also has a wider meaning referring to the loss of...
animal species; that is, animals that do not have predator responses for dealing with predators such as cats. Feral cats
introducedAn introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
to such islands have had a devastating impact on these islands'
biodiversityBiodiversity is the degree of variation of life forms within a given ecosystem, biome, or an entire planet. Biodiversity is a measure of the health of ecosystems. Biodiversity is in part a function of climate. In terrestrial habitats, tropical regions are typically rich whereas polar regions...
. They have been implicated in the extinction of several species and local extinctions, such as the
hutiaHutias are moderately large cavy-like rodents of the family Capromyidae that inhabit the Caribbean Islands. They range in size from , and can weigh up to . Twenty species of hutia have been identified, and half may be extinct. They resemble the nutria in some respects...
s from the
CaribbeanThe Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
, the Guadalupe Storm Petrel from Pacific
MexicoThe United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
, the
Stephens Island wrenThe Stephens Island Wren or Lyall's Wren was a nocturnal, flightless, insectivorous passerine.-Habitat:...
; in a statistical study, they were a significant cause for the extinction of 40% of the species studied. Moors and Atkinson wrote, in 1984, "No other alien predator has had such a universally damaging effect."
Feral cats, along with rabbits, some sea birds, and sheep, form the entire large animal population of the remote
Kerguelen IslandsThe Kerguelen Islands , also known as the Desolation Islands, are a group of islands in the southern Indian Ocean constituting the emerged part of the otherwise submerged Kerguelen Plateau. The islands, along with Adélie Land, the Crozet Islands and the Amsterdam and Saint Paul Islands are part of...
in the southern
Indian OceanThe Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...
.
Restoration
Because of the damage cats cause in islands and some ecosystems, many conservationists working in the field of
island restorationThe ecological restoration of islands, or island restoration, is the application of the principles of ecological restoration to islands and island groups. Islands, due to their isolation, are home to many of the world's endemic species, as well as important breeding grounds for seabirds and some...
have worked to remove feral cats. (Island restoration involves the removal of introduced species and reintroducing native species). As of 2004, 48 islands have had their feral cat populations removed, including
New ZealandNew Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
's network of offshore island bird reserves, and Australia's
Macquarie IslandMacquarie Island lies in the southwest corner of the Pacific Ocean, about half-way between New Zealand and Antarctica, at 54°30S, 158°57E. Politically, it has formed part of the Australian state of Tasmania since 1900 and became a Tasmanian State Reserve in 1978. In 1997 it became a world heritage...
. Larger projects have also been undertaken, including their complete removal from
Ascension IslandAscension Island is an isolated volcanic island in the equatorial waters of the South Atlantic Ocean, around from the coast of Africa and from the coast of South America, which is roughly midway between the horn of South America and Africa...
. The cats, introduced in the 19th century, caused a collapse in populations of nesting
seabirdSeabirds are birds that have adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations...
s. The project to remove them from the island began in 2002, and the island was cleared of cats by 2004. Since then, seven species of seabird that had not nested on the island for 100 years have returned.
In some cases, the removal of cats had unintended consequences. An example is
Macquarie IslandMacquarie Island lies in the southwest corner of the Pacific Ocean, about half-way between New Zealand and Antarctica, at 54°30S, 158°57E. Politically, it has formed part of the Australian state of Tasmania since 1900 and became a Tasmanian State Reserve in 1978. In 1997 it became a world heritage...
(off the coast of
TasmaniaTasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart...
), where the removal of cats caused an explosion in the number of rabbits, rats, and mice that harm native seabirds. The removal of the rats and rabbits was scheduled for 2007 and it could take up to seven years and cost $24 million.
Hybridisation with wild felids
Feral cats have interbred with
wildcatWildcat is a small felid native to Europe, the western part of Asia, and Africa.-Animals:Wildcat may also refer to members of the genus Lynx:...
s to various extents throughout the world, the first reported case occurring more than 200 years ago. The significance of hybridisation is disputed and hinges on whether the domestic cat is classified as conspecific with the wildcat or a separate species.(see
Genetic pollutionGenetic pollution is a controversial term for uncontrolled gene flow into wild populations. This gene flow is undesirable according to some environmentalists and conservationists, including groups such as Greenpeace, TRAFFIC, and GeneWatch UK.-Usage:...
) In some locations, high levels of hybridisation has led to difficulties in distinguishing a "true" wildcat from feral domestic and domestic hybrid cats, which can complicate conservation efforts. Some researchers argue that "pure" wildcats do not exist anymore, but this is disputed by others. One study in Scotland suggests that while "true" Scottish wildcats are unlikely to exist, the current wildcat population is distinct enough from domestic cats to be worth protecting.
Zoonotic risk
There is concern about the role of feral cat colonies,
wild dogsThe domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...
, and other native mammals, as a vector of diseases, particularly
toxoplasmosisToxoplasmosis is a parasitic disease caused by the protozoan Toxoplasma gondii. The parasite infects most genera of warm-blooded animals, including humans, but the primary host is the felid family. Animals are infected by eating infected meat, by ingestion of feces of a cat that has itself...
,
giardiasisGiardiasis or beaver fever in humans is a diarrheal infection of the small intestine by a single-celled organism Giardia lamblia. Giardiasis occurs worldwide with a prevalence of 20–30% in developing countries. In the U.S., 20,000 cases are reported to the CDC annually, but the true annual...
(esp. from beavers),
rabiesRabies is a viral disease that causes acute encephalitis in warm-blooded animals. It is zoonotic , most commonly by a bite from an infected animal. For a human, rabies is almost invariably fatal if post-exposure prophylaxis is not administered prior to the onset of severe symptoms...
(e.g. raccoons),
CampylobacterCampylobacter is a genus of bacteria that are Gram-negative, spiral, and microaerophilic. Motile, with either unipolar or bipolar flagella, the organisms have a characteristic spiral/corkscrew appearance and are oxidase-positive. Campylobacter jejuni is now recognized as one of the main causes...
,
ParvovirusParvovirus, often truncated to "parvo", is both the common name in English casually applied to all the viruses in the Parvoviridae taxonomic family, and also the taxonomic name of the Parvovirus genus within the Parvoviridae family...
and other diseases and parasites that can infect both humans and animals. Felids such as cougars and cats, the mammals they feed on, and undercooked meat and chicken are a source of
Toxoplasma gondiiToxoplasma gondii is a species of parasitic protozoa in the genus Toxoplasma. The definitive host of T. gondii is the cat, but the parasite can be carried by many warm-blooded animals . Toxoplasmosis, the disease of which T...
, which causes toxoplasmosis.
Population
A
feral cat colony (or "clowder") is a population of feral cats. The term is used primarily when a noticeable population of feral cats live together in a specific location and use a common food source. The term is not typically applied to solitary cats passing through an area. A clowder can range from 3-25 cats. Their locations vary, some hiding in alleyways or in large parks.
Members consist of adult females, their young, and some adult males. Unneutered males in a clowder fight each other for territory and for females. Some will be driven out to find another place to live.
Feral cats who have been trapped in many warm areas where fleas exist are usually found to have a large number of fleas, causing them to be anemic. Both the fleas, and the food source, if limited to garbage and rodents, cause the cats to have intestinal microorganisms (such as coccidia or giardia) and other parasites (commonly known as roundworms, tapeworms, and hookworms), which lead to diarrhea and subsequent dehydration. They also can have ear mites, ringworm, and upper respiratory infections. Others are wounded in mating-fights and die from the infected wounds. Still others eventually contract
feline immunodeficiency virusFeline immunodeficiency virus is a lentivirus that affects domesticated housecats worldwide and is the causative agent of feline AIDS. From 2.5% up to 4.4% of cats worldwide are infected with FIV...
or feline leukemia due to the constant transmission of blood and bodily fluids via fighting and sexual activity.
While all of these illnesses are quite treatable, there must be humans to intervene to stop these illnesses from becoming fatal. Due to the number of health problems to which they are subjected, and their fragile immune systems, kittens in the clowders usually do not survive .
Control and management
In
Trap-Neuter-ReturnTrap-Neuter-Return , also known as Trap-Test-Vaccinate-Alter-Release is a method of humanely trapping unaltered feral cats, spaying or neutering them, and releasing them back to the same location where they were collected...
(TNR), volunteers trap feral cats,
sterilizeNeutering, from the Latin neuter , is the removal of an animal's reproductive organ, either all of it or a considerably large part. The process is often used in reference to males whereas spaying is often reserved for females. Colloquially, both terms are often referred to as fixing...
them through
spaying or neuteringNeutering, from the Latin neuter , is the removal of an animal's reproductive organ, either all of it or a considerably large part. The process is often used in reference to males whereas spaying is often reserved for females. Colloquially, both terms are often referred to as fixing...
, and then release them, though some keep kittens or cats which are more tame. Variations of the program include testing and
inoculationFeline vaccination is the administration of antigenic material in cats to produce immunity to a feline disease. Vaccines can prevent or ameliorate the effects of infection by a pathogen. Currently, there are geographically defined core vaccines and individually chosen non-core vaccine...
against
rabiesRabies is a viral disease that causes acute encephalitis in warm-blooded animals. It is zoonotic , most commonly by a bite from an infected animal. For a human, rabies is almost invariably fatal if post-exposure prophylaxis is not administered prior to the onset of severe symptoms...
and other viruses and sometimes long-lasting flea treatments. TNR programs are only now being introduced in some urban and suburban areas, such as
AdelaideAdelaide is the capital city of South Australia and the fifth-largest city in Australia. Adelaide has an estimated population of more than 1.2 million...
. More recently, such programs have been introduced in
SydneySydney is the most populous city in Australia and the state capital of New South Wales. Sydney is located on Australia's south-east coast of the Tasman Sea. As of June 2010, the greater metropolitan area had an approximate population of 4.6 million people...
by the "World League for Protection of Animals". While various long-term studies have shown TNR is effective in stopping the breeding of cats in the wild and reducing the population over time, opponents of TNR frequently cite a study by Castillo (2003) as evidence TNR does not work. Many humane societies and animal rescue groups of varying sizes throughout the United States have some type of TNR program. The practice is endorsed by the
Humane Society of the United StatesThe Humane Society of the United States , based in Washington, D.C., is the largest animal advocacy organization in the world. In 2009, HSUS reported assets of over US$160 million....
and the National Animal Control Association. While the
United States Department of DefenseThe United States Department of Defense is the U.S...
does not formally advocate TNR, it does provide information to military installations on how to implement TNR programs. The main message from the department is that population control programs must be humane.
On islands, on which the vacuum effect does not apply, eradication methods include hunting, trapping, poison baiting and biological controls. For example on
Marion IslandThe Prince Edward Islands are two small islands in the sub-antarctic Indian Ocean that are part of South Africa. The islands, named Marion Island and Prince Edward Island, are located at ....
cats were infected with the
feline panleukopeniaFeline panleukopenia virus , also known as Feline infectious enteritis, Feline distemper, feline ataxia, or cat plague, is a viral infection affecting cats, both domesticated and wild feline species. It is caused by feline parvovirus, a close relative of both type 2 canine parvovirus and mink...
virus, which drastically reduced their population within six years. The remaining cats were killed by shooting.
Feral cats can also be controlled by larger native predators like
coyoteThe coyote , also known as the American jackal or the prairie wolf, is a species of canine found throughout North and Central America, ranging from Panama in the south, north through Mexico, the United States and Canada...
s,
dingoThe Australian Dingo or Warrigal is a free-roaming wild dog unique to the continent of Australia, mainly found in the outback. Its original ancestors are thought to have arrived with humans from southeast Asia thousands of years ago, when dogs were still relatively undomesticated and closer to...
es, or
foxFox is a common name for many species of omnivorous mammals belonging to the Canidae family. Foxes are small to medium-sized canids , characterized by possessing a long narrow snout, and a bushy tail .Members of about 37 species are referred to as foxes, of which only 12 species actually belong to...
es because many cats are too small to defend themselves against larger predators.
The multiple, managed, feral colonies at the
ColosseumThe Colosseum, or the Coliseum, originally the Flavian Amphitheatre , is an elliptical amphitheatre in the centre of the city of Rome, Italy, the largest ever built in the Roman Empire...
in
RomeRome is the capital of Italy and the country's largest and most populated city and comune, with over 2.7 million residents in . The city is located in the central-western portion of the Italian Peninsula, on the Tiber River within the Lazio region of Italy.Rome's history spans two and a half...
exceed 250 cats. Other notable colonies include the
Canadian Parliamentary CatsThe Parliamentary Cats are a collection of stray cats living in the precinct of Parliament Hill in Ottawa, Ontario. A small colony on the grounds, called the Cat Sanctuary, is set aside for them...
, and the cats of Jerusalem
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