When you speak to most people around the world, Hippos are often interpreted or stated as the animal that kills the most people in Africa every year.
Although I personally have my doubts around this statistic, it is important to understand the following facts:
- There are many villages along Africa's main rivers such as the Nile, Zambezi and Congo River, many of which are fishermen's villages.
- Many of the people living in these villages use the rivers to do their laundry and bathing, often in areas where many Crocodiles and Hippos are present.
- The majority of the local fishermen use dugout canoes and paddles and would often have to move between pods of Hippo to get to their preferred fishing spots.
The generic and colloquial name is derived from the greek hippo-potamos, which means water horse or river horse.
Hippos are characterized by their great size, their short, barrel shaped bodies, their smooth, naked skin, and their short, stout legs. Their heads are broad and heavy, with the eyes and nostrils mounted on top. Their mouths are large, and their jaws armed with tusk like canines and incisors. The upstanding ears are small in proportion to the head. The tail is short and flattened, with a sparse brush of bristles towards the tip.
The color of the body is a grayish-black with a pink tinge, and pinkish-yellow in the folds of the skin and around the eyes and ears.
Hippos are found widely on the African continent south of the Sahara, and were once found in the lower Nile.
Today Hippos are found in most large rivers in Africa, including the Nile, Zambezi, Chobe and most commonly in the Luangwa River where it is estimated to have the highest concentration.
An essential habitat requirement is sufficient open water in which they can submerge totally. They prefer shallow standing water near sandy banks on which they can bask in the sun. If they are undisturbed they will use these pools over a period of many years, if food supplies remain available to them within their range of normal movement.
Seasonal flooding may cause them to move temporarily from their established resting pools, but, provided that this has not altered their condition seriously, they will return when the flood subsides.
Among the angulates only hippos are truly amphibious, feeding mostly nocturnally on dry land and spending much of the day in the water, where mating and calving takes place. During daylight they live in social groups varying in size and composition, the group consisting of a territorial bull, females with calves, or bachelors in association. Solitary animals are generally territorial bulls or females about to give birth.
Territorial bulls can be extremely aggressive towards younger bulls especially during the drier months. Bulls will maintain territories for long periods of time, never giving them up voluntarily, often resulting in serious fights which could even lead to death. Territories are advertised and maintained through the bulls presence, through dominant behavior (gaping and posturing) and through ritualized defecation combined with urination.
Apart from territorial bulls, recognizable by the larger size of its head and thick neck, few dominance relationships seem to exist in hippo groups. The only stable associations are those of a cow and her young until these are fully grown at 6 to 8 years. When hippos depart to graze in the evenings, the social groups break up. Grazing areas are not monopolized or defended by any individual or group, as they are not territorially subdivided and change with the season and the availability of forage. Hippo do not spend the whole night feeding and may rest, lying down under bushes, or maybe even return to the water.
Adult hippos can remain under water for 5 to 6 minutes at a time, the young for much shorter periods. Just before submerging, they fill their lungs with air and, as the water closes over them, sphincter muscles close the nostrils and hearing duct to prevent the entry of water. On returning to the surface they empty the lungs with a loud blast, which can be heard over considerable distances. They may also exhale under water. Contrary to popular belief, hippos are not able to float, but in deep water push themselves to the surface with their hind feet. When swimming on the surface of the water, they propel themselves forward with a jumping action. The four toes are not webbed to aid swimming.
Hippos are selective nocturnal grazers, consuming up to 40 kg of grass per night. During the dry season grasses fail to yield enough crude protein to sustain hippos and, even though they are not adapted to feeding on aquatic vegetation, they are more often than not obliged to utilize it.
Like ruminants, hippos have a compound stomach with three compartments, but they have no rumen and do not ruminate. Grass is fermented in the stomach with the aid of micro organisms before passing into the small intestine.
Hippos breed at any time of the year although some carving peaks have been reported in the past.
Mating takes place in the water, with the female remaining submerged, except for brief intervals to breathe. The male's head is not submerged.
When she is about to calve, the female leaves the group and finds a secluded site in shallow water to give birth to a single young, its hind legs emerging first. They begin to suckle within a few minutes of birth, even underwater. Like adults, young hippos are unable to float.
When in deeper water a young hippo often sits on his mothers back. Calves do not appear to be able to remain under water for as long as the adults and normally submerge for only two or three minutes at a time.
Best places to view Hippo
Most of Africa's major river systems offer good hippo viewing. Some of the best destinations to view these incredible animals include Mana Pools National Park, Okavango Delta and South Luangwa National Park.
Yes - hippos can be extremely dangerous animals, especially when provoked or when their pathways to the water have been cut off. More often than not however, hippos will avoid confrontation and would prefer to move to the water when on land, and to deeper water when confronted in a river or lake.
So next time you are fortunate enough to view hippos in the wild, make sure that you enjoy spending time with these totally misunderstood creatures.
Till next time...