Aside from acting as a clean-up crew, the dogs also served as an early warning system in a wild and woolly world, signaling villages of approaching predators and perhaps even warring tribes. Over time, wild dogs became more trusting of people, and were thus effectively self-domesticated. It's likely that the first dogs to completely bond to people did so because they were raised by people from the time they were puppies. Today, no single animal species boasts the divergence of the modern domestic canine. From the sleek and dainty Whippet to the lumbering 150-pound Saint Bernard to the diminutive Chihuahua, it's hard to believe these variations are closely related.
Observers cite examples in mythology and art to track the history of the development of modern dogs.
By the time the Egyptians perfected their hieroglyphics and wall paintings 6,600 years ago, distinctive breeds had appeared, similar to today's Mastiffs and Greyhounds. Human relationships with dogs were first noted soon after that. Greek mythology tells how Xanthippus, the father of Pericles, owned a dog that swam by the side of his master for many miles to the city of Salamis. Alexander the Great named the city of Peritas in memory of his dog. There are also accounts of Greek legends of dogs that could heal the sick by licking them.