Scientists and archaeologists also have a story to tell in the Yukon. Their story is similar to ours and often correlates scientific fact to legend. They say that man was first evident in the Yukon about 15,000 years ago after our ancestors migrated over the land bridge known as Beringia which, during the last ice age, was a massive steppe connecting Siberia and Alaska. They slowly migrated into North America and the people who are now known as Yukon First Nations were part of some of the last waves of people to cross the land bridge. During this time the Yukon was also home to many animals who have gone extinct since then. Woolly mammoths, giant beavers, and giant bears are present in the stories during a time when animals and humans were interchangeable and the world around us was not as we see it today. Over thousands of years the people in the Yukon settled into their traditional territories and developed distinct languages and cultures, and this is how we define our various groupings today.