Your outdoor cat really is a wildlife-murdering machine, study says

Pet cats have an outsized impact on birds and mammals compared with their wild counterparts.

Amanda Kooser
Amanda Kooser
Freelance writer Amanda C. Kooser covers gadgets and tech news with a twist for CNET. When not wallowing in weird gear and iPad apps for cats, she can be found tinkering with her 1956 DeSoto.
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A domestic cat with a GPS tag. 

Roland Kays

The impact of pet cats on local birds and mammals has been a hot topic, especially since a 2013 study estimated that cats kill billions of birds and rodents each year. A new study took a close look at domesticated felines and the ecological impact they have on wildlife compared with wild predators. 

A team from North Carolina State University and the North Carolina Museum of Natural Sciences gathered GPS tracking data and prey-capture statistics from 925 domestic cats, primarily residents of the US, UK, Australia and New Zealand. 

The individual statistics for cats varied, with more-active hunters bringing home an average of 11.6 prey per month. The researchers adjusted the study numbers to account for prey that was eaten or otherwise not brought back home, and then compared the domestic cat numbers with prey counts and ranges for a similarly sized wild jungle cat.

The pet cats mostly stuck to a 330-foot (100-meter) area around their homes, but they made waves within those small territories. "We found that house cats have a two- to 10-times larger impact on wildlife than wild predators -- a striking effect," said NC State zoologist Roland Kays, lead author of a paper scheduled for publication this month in the Animal Conservation journal.  

"Humans find joy in biodiversity, but we have, by letting cats go outdoors, unwittingly engineered a world in which such joys are ever harder to experience," said NC State biologist Rob Dunn, co-author of the study.

Kays recommends keeping cats indoors in order to protect local wildlife. You can learn more about the cat-tracking project and view participating felines' GPS tracks at CatTracker.org.

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