They may be adorable but they each may have a killing streak a mile wide, says scientists. (credit: Chris Jackson – WPA Pool/Getty Images)

Studies Show That Cats Are Serious Killers

Although 70 percent of roaming house cats do not actively hunt and kill prey, 30 percent of them do. That’s enough to cut a swath of blood across 1 out of 3 American bird species and seriously declining their numbers.