By Jack Sommars
Benjamin Hart, DVM, PhD, who has studied animal behavior for almost 50 years, says that's one of the questions he hears most frequently from pet owners. Until recently, veterinarians like Hart could only speculate on the reason. Common theories included: The pet must be sick and needs to vomit. Or perhaps there is something wrong with his diet. But according to new research by Hart and his colleagues at the University of California–Davis, neither of these answers appears to be correct.