Parque Nacional da Gorongosa Moçambique

Description

From the Greek word meaning “river horse,” hippos are larger than most terrestrial mammals.  The hippo is a bulky, barrel-shaped amphibious mammal with an enormous muzzle.  The males can be up to 5 meters long, stand 1.5 meters high, and weigh 3,500 kilograms.  They are brown to grey-purple with a pink belly.  Hippos’ eyes, nostrils, and ears are located on top of their head, which allows them to surface for air while keeping the rest of their body submerged.  Their canines and lower incisors are large, especially in males, and constantly growing. 

Hippos have very thin skin and no sweat glands.  Hippos out of water in hot weather risk rapid dehydration and overheating because their skin loses water at several times the rate of other mammals.  They can spend 5-6 minutes submerged under water, but hippos cannot float because their heavy muscles weigh them down and cause them to sink. They do not drown, however, because they can paddle or walk along the bottom of the river. 

Despite spending much time in the water, hippos feed on land.  They have muscular lips up to half a meter wide that enable them to graze a broad swath and harvest short grasses.  They quickly consume 40kilograms of grass at night with little noise.  They play an important role in the ecosystem, as they keep grasses short for other animals and create important pathways to water sources.

Hippos live in pods of between five and twenty individuals. Pods fall under the rule of a dominant male who marks his territory along pathways by scattering dung on bushes and shrubs and in the water with a side-to-side beating of the tail. When in water, this action feeds the aquatic ecosystem by keeping the water chemistry in balance for other species and adding nutrients to the system. Male hippos protect their territory ruthlessly from intruders, and female hippos are especially aggressive when protecting their young.

How to See

Hippos prefer water sources with a gentle slope and firm bottom where herds can rest half submerged and calves can nurse without swimming.  In Gorongosa National Park, hippos are most commonly found in Lake Urema and the rivers and grasslands around the lake.

Hippos are herbivores and would rather run away than fight. Nevertheless, they can be highly aggressive and more deadly than many feared predators, including lions.  An angry hippo can run much faster than a human; they have been clocked in running dashes at 30 mph.

Status

IUCN: Vulnerable
Africa: Common
Mozambique: Common
Gorongosa: Uncommon

Conservation

Hippos play a very important role in the rehabilitation and restoration of the entire Gorongosa ecosystem.  In 1972, more than 3000 hippos were recorded and in 2007 only 160 were found.  Their low numbers are affecting the ecosystem’s balance because they keep grasses short and palatable for other herbivores that do not or cannot feed on very long grasses.

Historically the hippo population fed heavily on the grasses of the Urema floodplain.  This helps to expand the area that gets flooded and promotes the retention of grassland and fends off encroaching woodland.

The only natural predators of adult hippos are humans who seek them for their ivory tusks. However, hyenas, lions, and crocodiles prey upon hippo calves.  They are not endangered in Gorongosa but, due to habitat loss and poaching during Mozambique’s long wars, their population is very low compared to historical numbers.

From 2008 to 2014, 50 hippos will be reintroduced each year for a total of 350 hippos.  The goal of the reintroductions is to reach a hippo population of approximately 500.