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Jon Cox

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Cats pose a serious threat to biodiversity: Why do we accept it? What should be done?

According to the ASPCA, there are around 90 million owned domestic cats (Felis catus) in the U.S., and taking into account strays and feral cats, the total number is estimated to be as high as 160 million (1). Loss et al. (2013) estimates that cats roaming outdoors kill 1.4-­3.7 BILLION birds and 6.9­-20.7 BILLION mammals in the U.S. annually (2). Reptiles and amphibians such as snakes, lizards, frogs, etc., are also frequently killed by cats.

Cats are even more popular New Zealand, where they are contributing to declines of endemic birds such as the critically endangered kakapo (3), which have evolved in the absence of predators. Businessman/philanthropist Gareth Morgan is trying to gather support for legislation that would aggressively deal with stray and feral cats and potentially eliminate cats from New Zealand to take pressure off of threatened species (4 & 5). With Morgan’s plan, in addition to regulation that would reduce cat populations and increase owner accountability, residents would be encouraged to not replace their cats. As of now the majority of New Zealanders surveyed are in opposition to Morgan’s initiative.

Would a proposition like Morgan’s meet similar resistance in the U.S.? Probably, but is he on the right track? Would you personally support something like it for your state or country? Why or why not is it a good idea? Is this type of legislation necessary to curb the problem and protect wildlife? If you disagree, what are some alternatives? Will the aesthetics and familiarity of cats keep them off limits to such ideas in the opinions of the general public?

1. http://www.aspca.org/about-us/faq/pet-statistics.aspx
2. http://www.abcbirds.org/abcprograms/policy/cats/pdf/Loss_et_al_2013.pdf
3. http://www.avianweb.com/kakapo.html
4. http://www.npr.org/blogs/thetwo-way/2013/01/24/170191917/new-zealand-environmentalist-wants-to-eliminate-cats-to-save-birds
5. http://www.livescience.com/26525-cat-eradication-new-zealand-save-birds.html


Closing Statement from Jon Cox

Thanks to everyone who contributed to a thought provoking discussion!

I think we can all agree that we need to be responsible with our pets! For the sake of ecological and human health. And pet owners must realize that their carelessness is costly. Plans to completely eliminate cats from areas where they are very popular are pretty far fetched, but stricter regulation is a must, and domestic cats do NOT belong in the wild, period. Feral cats need to be seen and dealt with just as any other invasive species. However, extreme caution is necessary in any attempt to remove them where they have become established as a keystone species.

Check out Australian cat laws for a look at the legislation adopted by a people who cherish their native wildlife and do not want to see it be destroyed by invasives.

And lastly, we must keep in mind that invasive species are just one way in which we threaten biodiversity. Overexploitation and especially habitat loss pose even greater threats to species survival.

Thanks again!


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    May 6 2013: -=The Dangers of Cat Poop=-

    People who come in contact with cat poop are at a serious risk of being infected with the protozoan Toxoplasma gondii. This is a permanent infection that lays dormant in your body by forming cysts in nervous (aka your brain) and muscle tissue.

    Prognosis of people infected:
    - Increased rate of risk-taking personality traits
    - Higher incidence of automobile accidents (Webster et al., 2013)
    - Increased risk of OCD, Parkinson’s disease, Alzheimer’s disease, and suicidal tendencies

    Symptoms in rats:
    - Infected rodents show a reduction in their innate aversion to cat odors


    Webster, JP; Kaushik, M; Bristow, GC; McConkey, GA (2013 Jan 1). "Toxoplasma gondii infection, from predation to schizophrenia: can animal behaviour help us understand human behaviour?". The Journal of experimental biology 216 (Pt 1): 99–112. PMID 23225872.
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      May 6 2013: This is also an interesting article on the attitudes of cat vs. non-cat owners. I says here that cat owners were less concerned about water pollution from their cats as opposed to non-cat owners. It also has an astonishing number for the amount of poop that was produced by 9,000 cats in a year: 76.4 tons!

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      May 8 2013: Just to add to these comments, the parasite in cat poop, Toxoplasma gondii, is harming sea otters!

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        May 8 2013: Whoa what a crazy connection. This is a great reminder that we really live in one big, connected ecosystem. Actions produce ripple effects that travel much further than we might think.

        Here's a great BBC News article from 2006 about it with some quotes from Pat Conrad, author of the article you posted: http://news.bbc.co.uk/2/hi/4729810.stm

        It is a major cause of mortality in sea otters living off the Californian coast: Toxoplasma caused 17% of deaths in sea otters examined from 1998 to 2001.

        "We need to control the infections in sea otters and reduce the risk to humans by managing our cats more responsibly" - Conrad

        "But by keeping the cats indoors, we reduce the chance they're going to get infected by eating infected birds or rodents, and the chance they are going to shed their faeces outdoors." - Conrad

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