Hippopotamus Classification and Evolution

Hippopotamus Classification and Evolution

The Hippopotamus is a large semi-aquatic mammal that is found wallowing in the rivers and lakes across sub-Saharan Africa. Despite it's appearance, the Hippopotamus is actually thought to be most closely related to Whales as the two are thought to have had a common ancestor that existed roughly 54 million years ago. Also known as the Common Hippopotamus, it is one of two Hippo species that are found on the African continent with the other being the solitary and forest-dwelling Pygmy Hippopotamus which is only found in western Africa and is now Critically Endangered. Although the Common Hippopotamus remains abundant and widespread throughout it's current range, numbers are reportedly declining due to both hunting and habitat loss.

Hippopotamus Anatomy and Appearance The Hippopotamus has an enormous grey barrel-shaped body that can measure up to five meters in length and weigh more than four tonnes, and which is held up by short and stocky legs. One of the Hippopotamus's most distinctive features is their enormous jaws which contain two long canine teeth (tusks) which can grow up to 50 cm long and are used for fighting. Due to the fact that the Hippopotamus spends most of it's life resting in the water, they have a number of excellent adaptations to aid their semi-aquatic lifestyle including four webbed toes on each foot that help with swimming and walking on slippery banks, and the eyes, ears and nostrils of the Hippopotamus are situated on the top of it's head. This means that when the Hippopotamus's body is immersed in the water, they are still able to see, hear and breath whilst keeping cool in the hot sun.

Hippopotamus Distribution and Habitat

Although historically the Hippopotamus would have once been found across Europe and Asia, today they are confined to Africa south of the Sahara Desert. The Hippopotamus is always found close to water and tends to prefer areas close to grasslands, where they feed during the night. Hippos are most commonly found in the deep and slow-moving rivers and lakes in eastern and southern countries, with only a few smaller and more isolated populations still found in the west. The Hippopotamus is also a resident of the seasonal wetlands where they wade through the swampy waters by day and graze on the small islands at night. Although the Hippopotamus is still common throughout much of sub-Saharan Africa, their numbers have been declining with one reason being loss of their natural habitats mainly caused by land clearance for agriculture.

 Hippopotamus Behaviour and Lifestyle

The Hippopotamus spends up to 18 hours a day in the water to keep cool but when darkness falls, they venture out onto land and follow well-trodden paths to their feeding grounds, before returning to the water in the morning. The Hippopotamus is one of the largest and most feared animals in Africa as both males and females are known to be incredibly aggressive at points. The Hippopotamus tends to live in small herds containing between 10 and 20 individuals that are comprised of females with their young. The herd is led by the dominant male who will fiercely guard his stretch of river bank from both intruders and rival males, threatening them by opening his enormous mouth to expose the half meter long tusks. If this fails, the two will fight and deadly injuries often being caused. Although the dominant male will allow other males to enter his territory providing they are well-behaved, he holds the breeding rights with the females in the herd.