What exactly is a Dog?

Most folks think they know what a dog is. He's furry, got four legs, and a tail... he's man's best friend, right? But what exactly is a dog?
A dog is a canine mammal, a descendent of wolves from over 15,000 years ago. He has become domesticated through thousands of years of spending time with us two legged folks.  The scientific term for canines is Canis lupus familiaris.
Dogs are social animals and respond to a pack hierarchy. In other words, dogs have a leader and a pecking order, with some members being more dominant than others. Dogs are generally considered carnivores or meat eaters, but some circles consider dogs omnivores (an animal that eats meats and vegetables). Today, dogs carry many roles and task including that of companion animals, guide dogs, therapy dogs, hunting dogs, and even as television and film actors.