We're willing to tax plastic bags to save the planet, but are we willing to give up our pets? There's increasing evidence that our love of cats and dogs is having an adverse impact on the earth. Sure, pet owners experience joy and even the release of endorphins when they cuddle with Fluffy, but benign Fluffy is not.
A new report on the state of bird populations in the United States paints a grim picturefor the future diversity of bird species. The State of Birds survey indicates that fully one third of U.S. species are in decline. There are many pressures, most of them human, including habitat destruction. But the second biggest reason for the decline of birds: non-native species predation, which includes invasive critters, domestic animals, and house pets. Among pets, cats are the major threat. There are an estimated 77 million pet cats (pdf) in the U.S. (that doesn't count feral or stray populations which could more than double that number). Numbers vary but experts believe pet cats kill millions of birds in this country each year.
Urban cats are part of the problem in part because habitat fragmentation turns your yard from part of the larger wild system into an ecological island. Visiting birds are more isolated and vulnerable and can be more easily picked off by hunting cats who have the place staked out. Islands are particularly rough on stressed species: The place native birds are doing the worst is Hawaii. Another problem: despite best intentions, keeping cats indoors is problematic. since only about a third (35%) of pet cats are kept exclusively indoors, according to the American Bird Conservancy. Well-fed cats hunt. Cats with bells on their necks are successful predators too.
Then there's the problem of cat food. The New York had a recent column on the earth-devastating, or more accurately, sea-devastating, impact of cat food. In an op/ed, author Paul Greenberg, writes about the problem with his cat:
Coco, like most American cats, ate fish. And a great deal of them — more in a year than the average African human, according to Jason Clay at the World Wildlife Fund. And unlike the chicken or beef Coco also gobbled up, all those fish were wild animals, scooped out of the sea and flown thousands of carbon-belching miles to reach his little blue bowl....
The pet food industry now uses about 10 percent of the global supply of forage fish. The swine industry consumes 24 percent of fish meal and oil — fish oil being considered the best way to wean piglets. Poultry meanwhile takes as much as 22 percent, which means that even when Coco ate chicken, indirectly he was still eating fish.
The bottom line is that wild fish runs, on which whales, seals, orcas and other species depend, is being radically depleted worldwide, and much of the catch winds up in your cat's bowl. Many of the same arguments in favor of veganism for people apply to your pets. So does the idea of feeding pets locally with only land-based animals or crops.
But there's still another issue. Our pets, especially cats, are spreading diseases to wild species. Here's an example that's right in our front yard. Many people have heard that sea otters in California have tested positive for parasites spread by cat feces and kitty litter that makes its way to the ocean via run-off and sewer systems. But it also appears that this is also happening in Puget Sound.
The parasite is Toxoplasma gondii, and cats are the main carrier. A 2007 paper in the Journal of Wildlife Diseases found the parasite in river otters in the San Juan Islands. They had higher rates than otters tested in Alaska, which suggests that human proximity (and therefore domestic cat proximity) is a factor in spreading it. And previously, a 2001 study in the Journal of Parasitology (now there's some bathroom reading!) of harbor seals in the South Sound (Gertrude Island, near McNeil Island) found they also had the cat parasite.
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