You would think that the french poodle and the massive Saint Bernard don't have very much in common. But you would be wrong. They share the same ancestors: a single pack of wolves.

So, how did the wild wolf turn into the cuddly fur ball that follows our every move? The answer is evolution. It all started with a pack of wolves approaching hunter-gatherer camps in search of food. Those wolves that were tamer and less aggressive would have been more successful at this and more likely to befriend humans. Thus, the ones that were friendly received the food needed to survive, so they were the ones to reproduce and pass on their friendly personalities.

Over thousands of years, humans bred wolves to have characteristics they like. Eventually, the animals were so different from their original wolf ancestors, they became a new species: dog. When humans control what animals reproduce so the offspring will have favorable traits, it is called artificial selection.