FeralFeral cat
From Wikipedia, the free encyclopedia
A feral
cat is a domesticated cat that has returned to the
wild, or the descendants of such an animal. It is distinguished from a stray
cat, which is a pet cat that has been lost or abandoned,
while feral cats have never been socialized. The offspring of a stray cat can
be considered feral if born in the wild.[1] In many
parts of the world, feral cats are the offspring of unaltered domestic cats.
Behavior of feral cats
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.[1] 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.[2][3]
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. Such
behaviors are established while it is still a kitten being raised by its
mother.[2][4]
Life span and survival
Feral cats in
managed colonies can live long lives. A number of cats in managed colonies in
the U.K. died of old age.[5]:522 In the
U.S., the last cat in a managed colony in Washington,
D.C. died at age 17,[6] and
Zorro, the last cat of a colony at the Merrimack
River in Newburyport, Massachusetts, died in 2009
at age 16.[7]
A long-term
study of a trap-neuter-return (TNR) program in
Central Florida found that despite widespread concern about the welfare of
free-roaming cats, 83% of the cats studied had been present for over six years,
with almost half first observed as adults of unknown age. These time spans
compared favourably to the average lifespan of 7.1 years for pet cats reported
in a 1984 study,[8]:45 and to
the finding that only 42% of the pet cat population in the U.S. is more than 5
years old.[9]:1358
Adult feral
cats without human assistance have been found in surprisingly good condition.
In Florida, a study of feral cats admitted to a trap-neuter-return program
concluded that "euthanasia for debilitated cats for humane reasons is rarely
necessary".[10] A further
study of over 100,000 community cats (feral and stray) admitted to TNR programs
in diverse locations of the U.S. resulted in the same 0.4% rate of euthanasia
for debilitating conditions.[11] Rates of feline leukemia virus infection and feline immunodeficiency virus antibodies
in feral cats studied in North Carolina and Florida were similar to those of
owned cats.[12] The body
condition of feral cats entering a TNR program in Florida was described as
"generally lean but not emaciated".[13] However,
many community cats had suffered from parasites such as fleas and ear mites
before entering TNR programs.[9]
Control and management
Trap-neuter-return (TNR) involves trapping
feral cats, spaying or neutering them, and then returning them to the
place where there were originally trapped, where ongoing care is provided by
caregivers.[14] When
neutered, the cats receive vaccinations against rabies, and
attention to other medical needs, such as dental care and flea
treatments.[15]:115 TNR
programs are prevalent in several countries, including England,[5] Italy,[16] Canada
and the United States,[17] supported
by many local and
state governments. Various long-term studies have shown that TNR is
effective in stopping reproduction and reducing the population over time.[5][8][18] TNR
results in fewer complaints, as nuisance behaviors diminish following
neutering,[19]:16 and the
quality of life of the cats is improved.[9]:1359[13] The
practice is reported to save money[18]:294 and
garner more public support and better morale than efforts that involve killing
cats.[18]:297[20]:49
The
International Companion Animal Management Coalition advocates for TNR as a
humane method of controlling feral cat populations.[21] In the
U.S., the practice is endorsed by the Humane Society of the United States[22] and the
National Animal Control Association.[23] While the United States Department of Defense does
not formally advocate TNR, it provides information to military installations on
how to implement TNR programs,[24] with the
main message that population control programs must be humane.[25]
The multiple,
managed, feral colonies at the Colosseum in
Rome exceed 250 cats. Other notable colonies include the Canadian Parliamentary Cats and the
cats of Jerusalem.[26]
Low-level
killing feral cats in open population areas will increase their population, due
to dominant cats being targeted.[27]
History
During the Age of
Discovery, 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. Cats
were introduced to Tasmania in 1804 and had become feral by the 1840s. Feral
cats were reported on mainland Australia around Sydney in 1820.[28] It has
been suggested that feral cats could have been introduced accidentally to the
north-western coast in the 17th century from the wrecks of Dutch ships;
alternatively, they could have arrived earlier, possibly around the fifteenth
century, via mariners from Indonesia.[29]
Domestic and
feral cats have generally been found to eat a very broad range of vertebrate
and invertebrate prey. Preferred prey usually are small mammals, birds and
lizards, especially those with body weights under 100g. Feral cats in Australia prey on a variety of
wildlife. In arid and semi-arid environments they eat mostly introduced European
rabbits and house mice.
In arid environments where rabbits do not occur, native rodents are taken. In
forests and urbanised areas, they eat mostly native marsupials,
birds and reptiles.[29] On Macaronesian islands,
cats prey mainly on introduced mammals but also on birds and reptiles.[30]
Feral cats may
be apex predators in some local ecosystems.
In others, they may be preyed on by feral dogs, dingoes, coyotes, wolves, bears, cougars, leopards, lynx, hyenas,fishers, crocodiles, snakes, foxes, and birds of prey.
Effects on wildlife
Mice and rats
For thousands
of years, cats have been known for their ability to hunt mice and rats and keep
their populations under control. This ability is understood as the reason cats
became domesticated.[31]:68 The
relationship was more of convenience (or mutualistic) than dependence:
"Cats killed mice and rats, and humans provided lots of mice and rats to
kill since mice and rats lived in human settlements."[31]:68 A 2014
study examining 5,300 years of cat remains in an agricultural village of
Quanhucun, China,
provides early evidence of this dynamic, where cats protected grain stores by
eating rodents.[32][33]
If they are
well-fed, farm cats are
more dependable as effective ratters, as they are less likely to stray or hunt
further afield.[34]:110 Cats are
wary of adult rats, given their size,[34]:111 but are
particularly adept at hunting young rats.[34]:110
In 2002, feral
cats introduced to a flower market in Los Angeles, California,
were noted to have helped lower rat populations.[35] In Chicago's
47th Ward, feral cats were introduced in 2012 to help the city deal with the
rat problem there.[36]
Efforts to
eradicate feral cats in Ventura, California, were noted in 2002 to have
resulted in increasing numbers of rats, which were being monitored for health
problems such as bubonic plague.[35][37]
Birds
A 2013 study by
Scott R. Loss and others of the Smithsonian Conservation Biology
Institute and the US Fish and Wildlife Service suggested
that free-ranging domestic cats (mostly unowned) are the top human-caused
threat to wildlife in the United States, killing an estimated 1.3 to 4 billion
birds and 6.3 to 22.3 billion mammals annually.[38][39] These
figures were much higher than previous estimates for the U.S.[38]:2Unspecified
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.[38]:4
Advocates for
feral cats counter that Loss's study and earlier related studies have inflated
estimates of wildlife killed by cats in the U.S., based on unscientific
research that extrapolates from tiny samples and projects them onto whole
nations.[40] One
reviewer stated that Loss's study was filled with "numerous major flaws in
the statistical arguments made" that in his view made it
"unacceptable for publication".[41]:1 It was
unclear how predation rates were obtained, and then "applying these
estimates to all cats across the country is highly questionable."[41]:3 Extrapolation
was also misused when "Based on a small sample of cats over three summer
months in one specific geographic area, the authors see fit to extrapolate this
predation rate to all cats at all times of the year in all geographic regions
in the United States."[41]:3
Perhaps the
first U.S. study that pointed to predation by cats on wildlife as a concern was
ornithologist Edward Howe Forbush's 1916 report for the
Massachusetts State Board of Agriculture, The Domestic Cat: Bird Killer, Mouser and Destroyer of Wildlife: Means
of Utilizing and Controlling It.[42]
U.K. biologist
and cat behaviour expert Roger Tabor states that "studies from all around
the world have found that cats catch relatively few birds compared to small
mammals."[43]:135 The Royal Society for the Protection
of Birds states that there is no scientific evidence that cat
predation "is having any impact on bird populations UK-wide."[44] Moreover,
city cats have smaller ranges; in his research, Tabor found "the average
annual catch of the average London cat to be two items instead of the fourteen
of a village cat."[43]:135 Tabor
comments about some of the challenges of stalking birds for cats: "From
the cat's point of view not only do birds not play fair by flying and having
eyes that can see beyond the back of their heads, but they can positively cheat
by using loud alarm calls and throw the cat's chances of catching any
others."[34]:123
Island settings
pose particular challenges for wildlife. A 2001 study identified cats alone as
responsible for the plight of some island bird species, such as the Townsend's shearwater, socorro dove,
and theMarquesan ground dove.[45][45]:400 The same
study identified the greatest cause of endangerment of birds as habitat loss
and degradation, with at least 52% of endangered birds affected,[45]:399 while introduced species on islands, such as
domestic cats, rats and mustelids,[45]:403 affected
only 6% of endangered birds.[45]:399 Other
studies caution that removing domestic cats from islands can have unintended
consequences, as increasing rat populations can put native bird[46] and
mammal species[47][48] at risk.
Australia
See also: Cats in
Australia
Feral cats in
Australia have been linked to the decline and extinction of various native
animals. They have been shown to cause a significant impact on ground nesting
birds and small native mammals.[29] Feral
cats have also hampered any attempts to re-introduce threatened species back
into areas where they have become extinct as the cats have hunted and killed
the newly released animals.[49] 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 placentalmammal species.[50]
New Zealand
See also: Cats in New Zealand
The fauna of New Zealand 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 biodiversity. European explorers
and settlers brought cats on their ships and the presence of feral cats were
recorded from the latter decades of the 19th century.[51] 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.[52]
United Kingdom
In the U.K., The Royal Society for the Protection
of Birds states that there is no scientific evidence that cat
predation "is having any impact on bird populations UK-wide. This may be
surprising, but many millions of birds die naturally every year, mainly through
starvation, disease, or other forms of predation. There is evidence that cats
tend to take weak or sickly birds ... Those bird species that have
undergone the most serious population declines in the UK (such as skylarks, tree sparrows and corn buntings)
rarely encounter cats, so cats cannot be causing their declines. Research shows
that these declines are usually caused by habitat change or loss, particularly
on farmland."[44] This
evidence is despite the common practice in the U.K. of allowing owned cats
access to the outdoors,[53] which is
recommended to prevent feline obesity (p. 138) and behavior problems and
other health problems arising from confinement stress (p. 121).[43]
Islands
Consequences of introduction
The Stephens Island wren became extinct
within two years of the introduction of cats to Stephens Island.
Many islands
host ecologically naive animal species; that
is, animals that do not have predator responses for dealing with predators such
as cats.[54] Feral
cats introduced to such islands have had a
devastating impact on these islands' biodiversity.
They have been implicated in the extinction of several species and local
extinctions, such as thehutias from the Caribbean,
the Guadalupe Storm Petrel from Pacific Mexico, the Stephens Island wren; in a statistical
study, they were a significant cause for the extinction of 40% of the species
studied.[55] Moors and
Atkinson wrote, in 1984, "No other alien predator has had such a
universally damaging effect."[54]
Feral cats,
along with rabbits, some sea birds, and sheep, form the entire
large animal population of the remote Kerguelen
Islands in the southern Indian Ocean.
Although exotic mammals form the bulk of their diet, cats' impact on seabirds
is very important.[56]
Restoration
Because of the
damage cats cause in islands and some ecosystems, many conservationists working
in the field of island restoration 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 eradicated, including New Zealand's
network of offshore island bird reserves[57] and
Australia's Macquarie Island. Larger projects have also
been undertaken, including their complete removal fromAscension
Island. The cats, introduced in the 19th century, caused a collapse
in populations of nesting seabirds. 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.[58]
In some cases,
the removal of cats had unintended consequences. An example is Macquarie
Island, where the removal of cats caused an explosion in the number of rabbits,
rats, and mice that harm native seabirds[59][60][61] even if
the eradication was positioned within an integrated pest management framework.[62] The
removal of the rats and rabbits was scheduled for 2007 and it could take up to
seven years and cost $24 million.[63]
Hybridisation with wild felids
Feral cats have
interbred with wildcats to various extents throughout the world, the
first reported case occurring more than 200 years ago. The significance of
hybridisation is disputed. Some old books suggested that the wildcat was a
separate species to the domestic cat, but modern genetic analysis[64] has shown
that the domestic cat is a domesticated version of the near eastern wildcat (Felis sylvestra lybica),
which is of the same species as the European Wildcat (Felis
sylvestris sylvestris). In some locations, high levels of
hybridisation have led to difficulties in distinguishing a "true"
wildcat from feral domestic and domestic hybrid cats, which can complicate
conservation efforts.[65] Some
researchers argue that "pure" wildcats do not exist anymore, but
others dispute this.[66] 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.[67] In
addition to Scotland, wildcat populations notable gene introgression exist
also in Italy, Hungary, Spain and Portugal.[68] For a
discussion of this issue see The Encyclopedia of Mammals, OUP, pages 656–657.[69]
Disease prevalence
Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV)
are among the most common infectious diseases of cats. FeLV and FIV belong to
the retroviridae family, and both cause immunosuppression in
cats. Research has shown that the prevalence of these viruses among feral cat
populations is low and is similar to prevalence rates for owned cats in the
United States.[70]
Colonies
Population
A feral cat
colony 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.[71] 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, making them 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 virus 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, human intervention is necessary to prevent
them from becoming fatal. chat
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