Dog: man's best friend for over 33,000 years He's been man's best friend for generations. An ancient dog skull found in Siberia and dating back 33,000 years presents some of the oldest known evidence of dog domestication. When combined with a similar find in Belgium, the two skulls indicate that the domestication of dogs by humans occurred repeatedly throughout early human history at different geographic locations -- rather than at a single domestication event, as previously believed. "Both the Belgian find and the Siberian find are domesticated species based on morphological characteristics," said Greg Hodgins, a researcher at the University...