Cats that roam around outside are at risk of: becoming prey of wild predators, being attacked by domestic dogs, getting into fights with other cats, or getting hit by a car. Domestic cats as predators. Although many of our cats are affectionate pets, they can hunt as effectively as wild predators. Free ranging cats that roam outdoors are a threat to our local wildlife. With more than 70 million pet cats and over 60 million stray cats in the United States, scientists estimate that cats are responsible for killing billions of wild animals, such as birds, reptiles, and small mammals (e.g. rabbits, mice, voles, squirrels) in just one year.