More than 150 animal shelters now successfully use what are called Canine-ality and Feline-ality assessments to match prospective pet owners with just the right dog or cat. The quizzes have been so successful that euthanasia rates have been cut by 40%. "It really all comes down to matching," says Emily Weiss, an animal behaviorist and the Senior Director of Shelter Behavior Programs for the ASPCA, who devised the assessments when she worked at the Kansas Humane Society. "If I'm looking for a partner, be it a dog or cat or human, there are certain things I'm attracted to and there are things that I really don't want in my life."

Figuring out those "things" is the key. The process starts with potential adopters answering a list of questions regarding their expectations of a pet, ranging from "I want my dog to be playful - Not at All, Somewhat, or Very" to "I am comfortable doing some training with my dog to improve manners such as jumping, stealing food, and pulling on the leash - No, Some, or A Lot of Training."

On the other end, each animal's personality is categorized by shelter workers. The assessment tools include a four-minute hidden camera look at how a dog reacts to finding himself alone near a kitchen counter, bed or couch, with a trash can nearby. If the dog ignores the trash and hops right up on the bed, he's probably a Couch Potato, identified in the following way: "Like the easy life? I'm the perfect match for you, walking very short distances from the couch to the food bowl..." If instead she cruises the counter, she might be a Busy Bee, described as "on a mission to please you and myself..."

Weiss developed the assessments by studying the behavior of dogs on loan from homes to the Kansas Humane Society for 72 hours. Her staff watched the animals and then asked owners which behaviors were typical of the pets at home. The behaviors considered atypical were eliminated, and only lists of behavior categories matching an animal's personality in both stressed and non-stressed situations were included.

Researchers at the University of Minnesota's Stroke Research Center looked at 4,435 people, aged 30 to 75 years, who were participating in ongoing national government health research from the National Health and Nutrition Examination Study.

They found that over a 20-year period, those who had never owned a cat had a 40 percent greater risk of death due to heart attack and a 30 percent higher risk of death due to any sort of cardiovascular disease than previous or current cat owners. Researchers found no such protective effects for dog owners.

"Maybe cat owners tend not to have high-stress personalities, or they are just the type of people that are not highly affected by anxiety or high-stress situations," Qureshi said.

"I have heard an owner with a chronic, debilitating illness say that her cat gives her a reason to get up each day," said Marla McGeorge, veterinarian at The Cat Doctor in Portland, Ore.