An artist's impression of the new species of the ancient giant rhino, one of the largest mammals to walk on land (Credit: Yu Chen)

Modern-day rhinos, which weigh anywhere from 1,800 to 5,100 pounds, are no lightweights. However, they pale in comparison to their prehistoric cousin that roamed China about 26 million years ago. The massive mammal weighed 46,000 pounds — almost as much as four large African elephants. Standing at a height of 23ft (7m), it was also taller than a giraffe.