Sondra Siebenhaar

Discovering Mississippi mammoths While the massive Columbian mammoth — which weighed over 22,000 pounds (10 tons) and could grow to be over 13 feet (4 meters) tall — lived across North America alongside the mastodon, its diet largely consisted of grasses found in grassland biomes, which were rare on what’s now the east coast of the United States during that period, Phillips said. As a result, its fossils are much harder to come by in the area. "For every, say, 25 fragments or whole teeth of ...