Dogs were the first domesticated animal in history. Both species sewed their evolutionary destinies about 15,000 years ago.

Scientists are now trying to measure how this joint evolution affected dogs and humans. Owning a pet is known to help reduce stress levels, encourage positive emotions, and reduce the risks of cardiovascular disease. The first (although disputed) evidence of coexistence between men and wolves dates back to 25,000 year ago, says Aritza Villaluenga, researcher at the University of the Basque Country.