IUCN - The World Conservation Union, Gland, Switzerland, 28 February 2005. The results of the recently completed population and status assessment of the common and pygmy hippopotamus, undertaken in 2004 by the Hippo Subgroup of the SSC’s Pigs, Peccaries and Hippos Specialist Group, has highlighted some worrying trends in both species.
At the time of the last complete assessment of hippo populations in 1994, the common hippopotamus (Hippopotamus amphibius) was described as widespread and secure, with an estimated population of at least 160,000 animals. One of Africa’s most familiar large mammals, typically found wallowing in social groups in wetlands, rivers and lakes across sub-Saharan Africa, it was not considered threatened, using the IUCN Red List Categories and Criteria. Unfortunately since then, there have been substantial changes for the worse in several key countries which suggest a revision of its conservation status is necessary.
The survey reveals mixed fortunes for the common hippo across Africa. It is found in at least 29 countries, and numbers are still high in its principal strongholds of eastern and southern Africa, with large stable populations reported in Uganda, Kenya, Tanzania, Mozambique and Zambia. However, the situation elsewhere is more disturbing and declines have been reported in half the countries still supporting common hippos.
The total African population could now be as low as 125,000 (see map). The most catastrophic declines have occurred in the Democratic Republic of the Congo (DRC), where the ongoing political troubles have had a devastating impact. The population has been decimated as a result of unregulated hunting for bushmeat and for ivory (found in the hippo's canine teeth). From having the second highest estimated hippo population in Africa (30,000 in 1994 after Zambia’s 40,000), numbers have plummeted by 95%. Other large animals in the DRC, notably rhinos and elephants, have also suffered serious losses because of high levels of poaching.
After the DRC, the most serious declines are in West African countries, where numbers were already low, with only an estimated 7,000 individuals in widely scattered populations in 1994. This is also the area in which enforcement of legislation is weakest. The distribution of hippo populations is as important as population size as far as conservation of the species is concerned. Continuing declines in West Africa are an increasing cause for concern as this may lead to local extinctions.
The main reasons for the decline across Africa are unregulated hunting for meat and ivory. Estimates of the amount of illegally exported hippo teeth ivory continue to increase, and have increased sharply since the international elephant ivory ban came into effect in 1989. There is also a rise in the number of hippo-human conflicts, as human pressure on freshwater resources and habitats increases. Evidence of declines and growing threats from human activities point to a higher level of risk for these populations.
Pygmy hippo in the National Zoo, in Washington DC, USA - Photo courtesy of Glenn FeldhakePygmy hippopotamus
Unlike its large and gregarious relative, the pygmy hippopotamus (Hexaprotodon liberiensis) is much less well known or studied, restricted to a handful of countries in West Africa. As its name suggests, it is considerably smaller and is a secretive forest animal, living alongside rivers in densely wooded areas, alone or in small groups.
The pygmy hippo, already classified as Vulnerable using the IUCN Red List Categories and Criteria, is confined to four West African states: Liberia, Sierra Leone, Guinea and Ivory Coast. In 1994, the population was estimated to be at most, 3,000 animals, with a very fragmented distribution (see map). Logging and subsequent agricultural encroachment has continued to eat away at the pygmy hippo’s habitat throughout its range, and pushed it into ever decreasing and isolated parcels of remaining forest. In these fragments, the animals are increasingly accessible to subsistence hunters. Pygmy hippo populations have also been severely affected by the unrest and instability in the region, which has further reduced the effectiveness of pPygmy hippo in the National Zoo, in Washington DC, USA - Photo courtesy of Glenn Feldhakerotected areas and the enforcement of logging controls. In Liberia, for example, where most pygmy hippos are found, legal protection is incomplete and the level of protection poor. A key forest area, believed to support substantial numbers, the Cesto’s-Senkwehn rivershed, has recently been cleared and protection in the Sapo National Park, another key area, has been suspended.
At present, little is being done to protect the pygmy hippo or its habitat and it is likely that it will be placed in a higher category of threat as a result of the survey's findings.
Conservation action required
Both species of hippopotamus have been severely affected by the consequences of political instability in key range states. The effectiveness of designated protected areas and protective legislation has been greatly reduced. However, populations can recover if viable populations remain and effective protection is introduced once political stability returns. In Uganda, common hippos recovered after serious poaching losses during the civil war in the 1980s.
Pygmy hippo in the National Zoo, in Washington DC, USA - Photo courtesy of Susan StoneImmediate action is required to ensure the survival of the pygmy hippo, which has an estimated world population of less than 3,000. Effective habitat protection is critical, through the extension of the protected areas network and adequate enforcement of legislation against hunting and logging in these areas.
For the common hippo, effective protection against poaching and control of the illegal hippo ivory trade is the main priority throughout its range. In addition, the protected area network, particularly in West Africa, needs to be extended and adequately enforced to safeguard core populations that remain, and to prevent range contraction and local extinctions. Measures to minimize human-hippo conflicts also need to be developed, as exploitation pressures on hippo habitat rise and threats to these populations increase.
For further information, please contact:
Dr Rebecca Lewison, Chair SSC Hippo Subgroup
Andrew McMullin, IUCN Species Programme Communications Officer
Tel: +41 (0)22 999 0153