One of the largest land mammals that ever lived was the woolly mammoth.Woolly mammoths were very large, elephant-like creatures covered in long, thick, warm hair.They needed their warm coats because they lived during the last ice age.they became extinct thousands of years ago.In places such as Siberia, in Russia, thousands of woolly mammoths became mummies after they died.Today, some of these frozen mummies can be found in very good condition.