The Inuit are relatively recent arrivals to the Canadian Arctic. Their ancestors crossed the Bering Land Bridge to North America after the retreat of the Laurentide ice sheet, roughly 5000 years ago. (The multiple groups known as "Amerindians" or "First Nations Peoples" entered North America as much as 40,000 years ago.) The "Eskimoid" groups came later, migrating east across the Arctic coast. These people have been called "Eskimos" from a Cree word meaning "eaters of raw meat". It was this ability that ensured their survival in a harsh land. Those who ate their meat uncooked were able to make many needed vitamins within their bodies, thus avoiding nutritional diseases that affected the early explorers. In Canada, the preferred term is now "Inuit", which means "the people" or "people who are alive today".