[연구보고서] 생각보다 더 많은 동물을 죽이는 고양이
스미소니언 보존생물학연구소(Smithsonian Conservation Biology Institute)와 어류 및 야생동물관리국(the Fish and Wildlife Service)은 네이처에 발표한 연구 보고서를 통해 미국의 고양이들(야생 및 반려동물 포함)이 매년 24억 마리의 새와 123억마리의 포유류를 죽인다고 추정됨.
고양이에게 죽임을 당하는 야생동물의 수는 이전보다 2배~4배가량 높은 것으로 추정됨. 이는 자동차 사고, 살충제,독약, 고층건물 또는 풍차와 충돌 등 인간의 활동이 원인이 되어 죽는 야생동물 수보다 많은 수치임.
이러한 실험결과는 환경보호론자들과 동물복지옹호론자들 사이의 격렬한 논쟁을 불러 일으킬 것으로 예상됨.
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The impact of free-ranging domestic cats on wildlife of the United States
Scott R. Loss,1 Tom Will2 & Peter P. Marra1
Journal name: Nature Communications
Volume: 4,
Article number: 1396
DOI: doi:10.1038/ncomms2380
Received 06 September 2012
Accepted 12 December 2012
Published 29 January 2013
http://www.nature.com/ncomms/journal/v4/n1/abs/ncomms2380.html
Abstract
Anthropogenic threats, such as collisions with man-made structures, vehicles, poisoning and predation by domestic pets, combine to kill billions of wildlife annually. Free-ranging domestic cats have been introduced globally and have contributed to multiple wildlife extinctions on islands. The magnitude of mortality they cause in mainland areas remains speculative, with large-scale estimates based on non-systematic analyses and little consideration of scientific data. Here we conduct a systematic review and quantitatively estimate mortality caused by cats in the United States. We estimate that free-ranging domestic cats kill 1.4–3.7 billion birds and 6.9–20.7 billion mammals annually. Un-owned cats, as opposed to owned pets, cause the majority of this mortality. Our findings suggest that free-ranging cats cause substantially greater wildlife mortality than previously thought and are likely the single greatest source of anthropogenic mortality for US birds and mammals. Scientifically sound conservation and policy intervention is needed to reduce this impact.
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Study: Kill rates for cats higher than previously thought
By Natalie Angier
The New York Times, January 30, 2013
For all the adorable images of cats that play the piano, flush the toilet, mew melodiously and find their way back home over hundreds of miles, scientists have identified a shocking new truth: Cats are far deadlier than anyone had realized.
In a report that expanded results from local surveys and pilot studies, scientists from the Smithsonian Conservation Biology Institute and the Fish and Wildlife Service estimated that U.S. domestic cats — both the pet Fluffies that spend part of the day outdoors and the unnamed strays and ferals that never leave it — kill a median of 2.4 billion birds and 12.3 billion mammals a year, most of them native animals like shrews, chipmunks and voles rather than introduced pests like the Norway rat.
The estimated kill rates are two to four times as high as those previously bandied about, and they position the domestic cat as one of the single greatest human-linked threats to wildlife. More birds and mammals die at the mouths of cats, the report said, than from automobile strikes, pesticides and poisons, collisions with skyscrapers and windmills, or other similar causes.Peter Marra of the Smithsonian Conservation Biology Institute, and an author of the report, said the mortality figures that emerge from the new model “are shockingly high.”
”When we ran the model, we didn’t know what to expect,” said Marra, who performed the analysis with his colleague, Scott R. Loss, and Tom Will of the Fish and Wildlife Service. “We were absolutely stunned by the results.”
The study appeared Tuesday in the journal Nature Communications.
The findings are the first serious estimate of just how much wildlife the country’s vast population of free-roaming domestic cats manages to kill each year.
”We’ve been discussing this problem of cats and wildlife for years and years, and now we finally have some good science to start nailing down the numbers,” said George H. Fenwick, the president and chief executive of the American Bird Conservancy. “This is a great leap forward over the quality of research we had before.”
In devising their mathematical model, the researchers systematically sifted through the existing scientific literature on cat-wildlife interactions, eliminated studies in which the sample size was too small or the results too extreme, and then extracted and standardized the findings from the 21 most rigorous studies. The results admittedly come with wide ranges and uncertainties.
Nevertheless, the new report is likely to fuel the sometimes vitriolic debate between environmentalists who see free-roaming domestic cats as an invasive species — super-predators whose numbers are growing globally even as the songbirds and many other animals the cats prey on are in decline — and animal welfare advocates who are appalled by the millions of unwanted cats (and dogs) euthanized in animal shelters each year.
Most concur that pet cats should not be allowed to prowl around the neighborhood at will, any more than should a pet dog, horse or potbellied pig, and that cat owners who insist their felines “deserve” a bit of freedom are being irresponsible and ultimately not very cat friendly. Through recent projects like Kitty Cams at the University of Georgia, in which cameras are attached to the collars of indoor-outdoor pet cats to track their activities, not only have cats been filmed preying on cardinals, frogs and field mice, they’ve been shown lapping up antifreeze and sewer sludge, dodging under moving cars and sparring violently with much bigger dogs.
”We’ve put a lot of effort into trying to educate people that they should not let their cats outside, that it’s bad for the cats and can shorten the cats’ lives,” said Danielle Bays, the manager of the community cat programs at the Washington Humane Society.
Yet the new study estimates that free-roaming pets account for only about 29 percent of the birds and 11 percent of the mammals killed by domestic cats each year, and the real problem arises over how to manage the 80 million or so stray and feral cats that commit the bulk of the wildlife slaughter.
The Washington Humane Society and many other animal welfare organizations support the use of increasingly popular trap-neuter-return programs, in which unowned cats are caught, vaccinated, spayed and, if no home can be found for them, returned to the outdoor colony from which they came. Proponents see this approach as a humane alternative to large-scale euthanasia, and they insist that a colony of neutered cats can’t reproduce and thus will eventually disappear.
Conservationists say that, far from diminishing the population of unowned cats, trap and release programs may be making it worse, by encouraging people to abandon their pets to outdoor colonies that volunteers often keep lovingly fed.
”The number of free roaming cats is definitively growing,” Fenwick of the bird conservancy said. “It’s estimated that there are now more than 500 TNR colonies in Austin alone.”
