According to the History Channel, hippos were hunted in ancient Egypt because they were dangerous, ruined farmers' crops, overturned boats and stampeded. They run faster than people and have strong, destructive jaws. Even in modern Africa, hippos are considered the most lethal animal aside from mosquitoes, which quickly spread diseases.
There is some speculation that Egypt's young King Tut was killed by a hippo. Pharaohs are known to have hunted hippos, and it's likely that 19-year-old Tutankhamen was no exception. His embalming was unusual in that his heart and chest wall were missing, and several of his ribs were broken. An Egyptologist from California State University suggests that these are signs that he was the victim of a deadly hippo attack.