When the Ice Age began, some animals could not adapt to the cooler temperatures, so they died out. Many animals that survived and thrived in the colder climate were large mammals.
We call these megafauna (Greek megas means “big,” and Latin fauna means “animals”). Mammals are warm-blooded animals whose temperature remains relatively high and fairly constant, regardless of the surrounding temperature. Most mammals are covered with fur or have some hair. Over thousands of years, many mammals developed new ways to live in the harsh climate.