Many cats hunt outside at night, but not for rats or mice, UGA researchers find.

Thousands of pet cats in Athens might turn into hunters at night.

But they're probably not catching rats and mice, researchers at the University of Georgia recently discovered.

Instead, cats whose owners let them out at night seem to prefer small reptiles and amphibians, such as fence lizards, or native mammals, such as voles, said professor Sonia Hernandez of UGA's Warnell School of Forestry and Natural Resources.

Hernandez also works with UGA's Southeastern Cooperative Wildlife Disease Study.

Working with the National Geographic Society and local cat owners, Hernandez and her graduate students actually fitted about 60 Athens cats with little video cameras they dubbed kitty cams.

The owners agreed to put the cameras on their kitties nightly for a few months in 2010 and 2011 in exchange for a full cat physical.

The little motion-activated cameras saw and recorded what the cats did when they weren't sleeping.

Cats sleep or lie waiting a lot of the time, Hernandez told about 100 people last week in a talk at the UGA College of Veterinary Medicine.

"We got to know the undercarriages of cars very well because the cats spend so much time there," Hernandez said.

And not all that go out at night actually stalk or kill prey - less than half, she said. The ones that do hunt, she said, are likely to be young and male.

Still, if the proportions Hernandez and her students saw looking at video from 55 cats hold up across the rest of Athens, the city's cat population might kill tens of thousands of birds every year, as well as thousands of other creatures, she said.

Cats who go out also are exposed to hazards, such as cars and disease, she said. Cats kept indoors are healthier and live longer than cats that can roam, she said. None of the 55 cats fitted with kitty cams got hurt during the study, but one was hit by a car after the study ended.

The researchers also found that cats don't bring home most of what they kill. They left about half the animals they killed lying there, ate about 28 percent and brought home 23 percent, about a fourth, she said.

Researchers don't know if feral cats have the same hunting patterns as owned cats whose owners let them roam.

Hernandez eventually hopes to find a colony of feral cats to study.

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