Everything you need to know about Africa’s hippos
A characteristic and unmistakable resident of Africa’s rivers and lakes, the hippopotamus is a semiaquatic heavyweight whose blubbery barrel-like torso is supported by disproportionately short and stumpy legs. It is has a thick hairless purplish-grey hide, a massive head with ears, eyes and nostrils placed high on the roof of the skull, and a cavernous mouth that regularly yawns open to reveal a monstrous set of canines.
Hippos are not regarded to be one of the Big Five, but in many respects this feels like an oversight. These aquatic behemoths are considerably bulkier than lions, leopards, buffalos or black rhinos, and they’re probably more dangerous to humans than any other African mammals. Despite this, seeing or hearing hippos in the wild is a highlight of any African safari, and here we introduce you to some fascinating facts about these unique and remarkable creatures.
- The name hippopotamus derives from the Greek hippos potamos, which translates as “horse of the river”, while pre-20th century taxonomic systems classified hippos alongside pigs. However, fossil evidence and DNA testing indicates that they are more closely related to cetaceans (whales and dolphins) than to horses or pigs, or for that matter to any other living creatures.
- Hippos customarily spend most of their daylight hours submerged in a river, lake, marsh or similar watery habitat. Adults need to surface to breathe every 5-8 minutes, and are able to do this in their sleep. Females give birth underwater and new-borns need to surface almost immediately to take their first breath.
- Although we tend to think of hippos as aquatic, they are essentially terrestrial feeders, emerging in the late afternoon to crop around 100lb of grass overnight before returning to the water in the early hours. Especially in the dry season, hippos often need to walk long distances to meet their nightly grazing requirement.
- Hippos are very gregarious and strongly territorial. They typically live in pods (also called bloats or schools) of up to 30 individuals, presided over by an alpha male. Dominant males are viciously intolerant of other adult males and will defend their status in protracted toothy fights that usually end with a standoff, but also frequently result in the incumbent inflicting a fatal bite on the challenger, or vice versa.
- Surprisingly, given their aquatic habits, hippos cannot swim. Instead, they tend to shuffle along the lake or river floor, seldom straying into deep water. For this reason, any given hippo pod will generally be seen in the same place day after day, though it will relocate occasionally due to seasonal or other fluctuations in the surface level. In deeper water, hippos can retain some buoyancy by holding their breath to stay afloat.
- Among non-marine mammals, the hippo is exceeded in bulk only by the African elephant, Asian elephant and white rhino. A large male hippo might weigh in at 8,000lb, almost ten times as much as the average zebra.
- Although hippos are strictly vegetarian, they reputedly kill more people than any other wild African mammal. This is generally by accident rather design. Despite their lumbering appearance, hippos can easily attain a running speed of 20 miles per hour, and when disturbed they typically make a panicked charge to the safety of the water, mowing down anything that gets in their path. For this reason, safarigoers are advised to be very cautious when walking in the vicinity of lakes and rivers, especially around dusk and dawn, when hippos are most active.
- Hippos are among the most long lived of large mammals. In the wild, they frequently make it into their 40s, while captive individuals often pass the half-century mark. The oldest hippo on record is a female called Bertha who died in 2017 at Manila Zoo in the Philippines aged 65.
- The hippo’s far-carrying calls rank among the most evocative sounds of the African bush. Most typical is an explosive snorting grunt or chortle that will quickly become familiar to anybody staying in a camp or lodge near a river or lake. Competing male hippos also emit a loud chilling roar that could be mistaken for a lion.
- The family Hippopotamidae comprises just two extant species. These are the familiar and widespread common hippopotamus Hippopotamus amphibius and the Endangered pygmy hippopotamus Choeropsis liberiensis, fewer than 2,000 pf which survive in West Africa. Although both species are now endemic to sub-Saharan Africa, the common hippopotamus was resident along the Egyptian Nile into historic times (it is referred to in the works of Pliny the Elder) and fossil evidence indicates it once ranged as far north as the British Isles. Elsewhere, three hippo species became extinct on Madagascar within the past 1,500 years, and several dwarf species survived in parts of Mediterranean Europe until the end of the Pleistocene.
- The common hippopotamus is listed as Vulnerable on the IUCN Red List. Its range has contracted greatly in the past century, largely due to subsistence hunting and habitat loss. Today, the total wild hippo population probably stands at around 120,000 individuals, roughly half of which are resident in Zambia or Tanzania. Other important strongholds include Botswana, Zimbabwe, Uganda, Kenya, Malawi, South Africa, Rwanda and the Congo. Numbers are far lower in West Africa.
- Hippos are commonly seen in several African safari destinations, especially those that include sizeable waterways. My nomination for the ultimate hippo destination is Tanzania’s Katavi National Park, where aggregations of several hundred an be seen in pools along the Karuma River in the late dry season (Sept-Nov). Other great hippo-watching reserves include Nyerere National Park (Tanzania), South Luangwa National Park (Zambia), Murchison Falls National Park (Uganda) and Lakes Naivasha and Nakuru in Kenya’s Rift Valley.