Happy National Pet Day! It's believed that h umans started domesticating dogs more than 30,000 years ago. That's 10-20,000 years before cats waltzed into the lives of humans and domesticated themselves. It's also thousands of years before horses and ruminants (sheep, cattle, goats, etc) were put to use by enterprising homo sapiens. So basically, we've been keeping pets for a very, very long time. While pets have been found in tombs - both mummified and not - it feels as though our animals are b…