A herd of hippos rest on the edge of the water in Africa.

Hippos are social animals and depend on a group to be happy. Although Mzee is Owen’s friend, scientists have worried that Owen may need the company of other hippos as he grows older. Scientists have also worried that he would hurt Mzee unintentionally. A full-grown hippo could crush a tortoise with one blow of its foot.

Size Comparison Diagram

Adult Hippo

Adult Giant Tortoise