04/11/2012 07:58 am ET Updated Apr 11, 2012

National Pet Day: Pets That 'Diagnose' Health Problems

Your furry friend can be taught to roll over, fetch, go in her litter box, chirp your favorite song -- but pets can also be trained to detect serious illnesses, often helping their owners get critical care fast.

Unlike Paul The Octopus, the miraculous mollusk that predicted a number of World Cup soccer game outcomes seemingly by ESP, pets probably have some harder evidence to go on. While animal behavior experts still don't know much about the exact process, it's likely that animals "diagnose" by detecting subtle changes in smells given off by chemicals in the body when disease is present.

In honor of National Pet Day, take a look at the life-saving pets below, and tell us in the comments if you've ever had a pet "diagnose" you.

pets that diagnose

For more on pet health, click here.