Chalicotherium ("Pebble Beast") was a large prehistoric mammal from the Late Oligocene to Early Pliocene that were distantly related to modern horses, tapirs and rhinoceroses, but were really a branch of their own. These were the typical species that is most well understood.
Chalicotherium was a mammal that stood almost three meters tall. Much like gorilla's, they walked on their knuckles in order to protect their long claws. These powerful limbs were very effective defensive weapons against predators, but these herbivores more often used them to hook down branches to get at the softest leaves.
Although Chalicotherium may have walked like gorillas and ate like pandas, their closest modern relatives are actually horses.