2 Types of Hippos: Species, Subspecies and Photos

The hippopotamus, also known as the river horse, is among the heaviest land mammals in Africa. Although there are only two types of hippo species, they display diversity. This article explores their varying physical traits, behaviors, and habitats, including their subspecies. Read on to learn more.

Hippopotamus Classification

The Hippopotamidae family consists of large mammals belonging to the Artiodactyla order. There are two extant hippo species: the common hippopotamus and the pygmy hippopotamus. 

The common hippopotamus is the only living species of its genus in sub-Saharan Africa, staying near water. In contrast, the semi-aquatic pygmy hippopotamus inhabits the dense forests and swamps of West Africa.

Read More: Hippopotamus Facts.

2 Types of Hippopotamus Species With Subspecies

1. Common Hippopotamus (Hippopotamus amphibius)

The Common Hippopotamus, or the River Hippopotamus, dominates the African landscape, ruling sub-Saharan Africa's lakes, rivers, and mangrove swamps. 

A male hippo can reach 3,260 lb. Despite its massive size, it is surprisingly fast, reaching up to 22 miles per hour on land on short distances. 

One of its most distinctive characteristics is the secretion of "blood sweat," which acts as a natural sunscreen and antibacterial agent. 

Male hippos reach maturity at 7.5 years old, while cows are 5 to 6 years old. After an eight-month gestation period, a female hippo isolates herself from the group. It gives birth to one calf on land or in shallow water. 

Interestingly, calves fold their ears and close their nostrils as they nurse on female hippos underwater. Moreover, this nocturnal herbivore can consume around 80 pounds of grass overnight. Adults have no known natural predators, but lions, hyenas, and crocodiles endanger young hippos.

Despite their formidable size, Common Hippos are not sociable. While they form groups, they do so primarily for protection rather than companionship.

The hippos are a vulnerable species, facing a population decline due to poaching and civil unrest¹. Elephant ivory substitutes, such as hippo teeth, heighten demand in illegal markets. Conservation efforts are vital, yielding slight improvements in protected areas.

Here are five subspecies of the common hippo with differences in their skulls and geographic ranges.

Nile Hippopotamus (H. a. amphibius)

The Nile Hippopotamus spread from Gambia to Mozambique and has historically roamed Egypt. Its skull has a less protruding pre-orbital area, a raised upper side, an extended lower jaw joint, and larger molar teeth.

East African Hippopotamus (H. a. kiboko)

This particular hippo variant, native to East Africa and primarily spotted in Kenya and Somalia, is distinctively slighter and fairer than its counterparts. Characteristics include broadened nostrils, a mildly elongated snout, and notably curved orbits.

Cape Hippopotamus (H. a. capensis)

The Cape Hippopotamus subspecies is identified by its broader orbits and exclusive to Zambia and South Africa regions.

West African Hippopotamus (H. a. tschadensis)

The West African or Tchad hippopotamus is a subspecies of the common hippopotamus found in the Chad Basin, spanning parts of Chad, Nigeria, Cameroon, and Niger. It showcases features like a shorter, broader face and noticeable, front-facing eye sockets.

H. a. constrictus

This subspecies, spanning the southern Democratic Republic of Congo to Angola and Namibia, is identified by a thicker area before the eye, a shorter snout, a flatter top surface, a less pronounced jaw joint, and smaller molar teeth.

2. Pygmy Hippopotamus (Choeropsis liberiensis/Hexaprotodon liberiensis)

The Pygmy Hippopotamus is native to the dense forests and marshy swamps of West Africa. Unlike its larger relative, it is only half its height and weighs only a fraction. It measures 69 inches long and stands 39 inches tall at the shoulder. 

Moreover, the pygmy hippo lives in the water more than on land. While these animals weigh up to 606 pounds, they move with the grace and agility of a jungle ballerina.

This solitary creature spends the day hidden in cool rivers or wallows, venturing only at night to forage for food. It eats ferns, broad-leaved plants, grasses, fruits, small insects, and worms. 

Pygmy hippos are facing declining numbers due to habitat destruction from commercial plantations², mining, and shifting agriculture. Intensified bushmeat hunting exacerbates their plight, warranting their endangered status. With fewer than 2,500 mature individuals, a 20% population decrease over two generations is projected.

Extinct Hippo Species

Historically, the hippopotamus family exhibited diversity. Several extinct species offer glimpses into their past.

Madagascar was home to three such extinct species. The Madagascan Dwarf Hippopotamus, known only through skeletal remains, disappeared after 1500. Another species, Lemerle's Dwarf Hippopotamus, is prominently featured in Malagasy oral legends. Its prevalence in folklore prompted the IUCN to categorize it as recently extinct. Lastly, the Hippopotamus laloumena stands as Madagascar's oldest hippopotamus species, dating back to the Pleistocene and Holocene periods.

The geographical spread of extinct hippos also extended beyond Africa. For instance, Hexaprotodon, an extinct hippopotamus genus known from Asia, earned its name - "six front teeth" - due to its distinctive fossil forms. 

These extinct hippos remind us of a time when their diversity reigned supreme, emphasizing the need to protect the living ones.

Conclusion

Both hippopotamus species consume large amounts of vegetation, which shapes their landscape and contributes to the nutrient cycle and seed dispersal. 

However, human activities such as habitat destruction and hunting threaten their survival, leading to declining hippo populations. Their decline could have far-reaching consequences for the broader ecosystems they support and the biodiversity they help sustain. 

Comprehensive conservation efforts should address these threats and protect these creatures.