Hippopotamus at the Grumeti River Lodge

The hippopotamus is the third-largest land mammal after the elephant and rhinoceros. The name roughly translates as river-horse in ancient Greek, due to the fact that they spend most of their time in the water. Hippos are spread all over Africa and number up to 150,000 in total, with the largest populations being in Tanzania and Zambia.

Characteristics

The closest relatives to hippos are cetaceans such as whales. They are large, weighing up to 3.5 tonnes, and this huge weight gives them the appearance of slow creatures. However, when they run they can reach speeds of up to 18 mph in short bursts, meaning they can easily outrun a human.

Sometimes hippos may look pink, and this is due to a substance that they secrete from their skins that protects them from the sun. Hippos can be very aggressive creatures, making them the most dangerous animals in Africa.

Lifestyle

Hippos are mainly plant-eating animals. They are semi-aquatic, spending most of their lives in rivers and lakes, and only venturing out at night to graze on short grass. During the day they keep cool and prevent their skins from drying out by bathing in the water or mud.

They come in groups of up to 100 at the most, but generally the bulls preside over groups of up to 30 females. They generally huddle together in the water, but the reason for this is unknown because they are not particularly social creatures.

Threats

Hippos face two key threats to their survival: poaching and habitat loss. They are killed for their meat and their ivory teeth, but they are perhaps more threatened by the loss of fresh water habitats across Africa due to human settlement and the spread of agriculture. The pygmy hippo, a sub species, is threatened mainly by logging in its forest habitat.

This has led them to be declared a ‘vulnerable species’ by the World Conservation Union (IUCN), which placed them on the Red List in 2006. This came after a decline of 20% had been recorded since a decade earlier. One of the most severe drops was in Virunga National Park in DR Congo. There were about 29,000 hippos living here in the 1970s, which went down to less than 1,000 over 30 years mainly as a result of war.

Conservation

There are a number of conservation schemes in place now to protect hippos. One of these is in Lake Edward in DR Congo which has seen its population decline from over 27,000 in 1959 to just a few hundred today.

One group is the IUCN/SSC Hippo Specialist SubGroup, a specialist section of the World Conservation Union. But there are many other charities such as WWF and the International Fund for Animal Welfare (IFAW) that are committed to protecting all types of animals across Africa including hippos.