The hippopotamus is one of the most dangerous animals in Africa - and for this reason one of the most difficult to study. Professor of Zoology and scientist Hans Klingel enjoys challenges. After spending twenty years studying zebras, the "Queen Elizabeth" National Park in Uganda asked him to research hippopotami – and he became the World specialist in them.

Despite the dictatorship of Idi Amin Dada and often at the risk of his life, Hans never stopped his mission. The species is threatened by poachers who kill the animals for their meat and the ivory from their teeth. Hans Klingel's observations have shown that the hippopotamus makes a major contribution to the African ecosystem.

With his wife Ute, Hans Klingel also studies an enigmatic and virtually unknown animal - the giant forest hog, one of the last African species discovered.