Most hippopotamus live by a herbivorous diet, but they don’t all eat the same foods. While they spend most of their time in water, aquatic foods actually make up only a small amount of what they eat. That goes for both pygmy and common hippos. So what do hippos eat exactly? and how does it differ between the species?
Types of Hippo and What They Eat
There are only two types of hippo alive in the world today, the common hippo and the pygmy hippo. They both look very similar in terms of features but the pygmy hippo is much smaller. Despite their similarities they are actually belong to different genus. In fact, technically the pygmy hippo is not actually a hippopotamus at all.
Both the common hippopotamus and pygmy hippopotamus have a herbivorous diet, with some exceptions. The common hippo prefers to eat lots of grasses, and where available they will eat fruits and different reeds too. Pygmy hippos have a more varied, and strictly herbivorous diet.
What Do Hippos Eat? (Hippopotamus amphibius)
The modern hippopotamus is also sometimes called the common hippopotamus or river hippopotamus. It is the only extant member of the genus Hippopotamus, and is the third largest living land mammal on the earth.
In the wild, hippos may stay in the waters all day, however, at night they come out of the lakes, swamps and ponds and head for the grass to graze. For a long time hippos were considered to be strictly herbivorous, and because of their massive size, hippos are considered to be megaherbivores. However, some have been observed eating meat, and these observations are increasing. This makes at least some hippos omnivores.
The first observations of carnivorous behaviour were during a drought year in the 1990’s and it was thought that the risk of starvation played an impact on this. However, more recent observations of meat eating in periods of normal food availability have now also occurred.
Regardless of if hippo’s eat meat or not, the bulk of a their diet is made up of short savannah grass. They eat this every night, and will subsidise their diet with various reeds, shoots and fruits.
Aquatic vegetation makes up only a small portion of their diet, despite spending so much time in the water. While hippos do mostly travel at night to feeding grounds, they do on occasion leave the water in daylight to take in some grass from the banks of their watercourse. These areas are called hippo lawns, as the grass is always very short.
Of those that do eat meat, they may be opportunistic scavengers, and have been known to eat from the carcases of wildebeest, kudus and zebras. They have also been known, on rare occasion to resort to cannibalism of other hippos.
They have a relatively nutrition poor diet, but their slow rate of digestion helps them to get the most benefit out of their food.
The majority of a hippos diet is made up of:
- Water plants (rarely)
- Grasses (mostly, particularly savannah short grass)
- Young shoots
In captivity, hippos are fed a wider variety of foods and pellets, to provide balance fibre and nutrition. This is not always available in the wild.
What do Baby Hippos Eat?
A hippo calf will begin to eat grass at about 3 weeks old, however, it will continue to nurse from its mother for about a year. Serious grazing on grass at night begins at around 5 months old.
What Do Pygmy Hippos Eat? (Choeropsis liberiensis)
The pygmy hippopotamus is herbivorous, feeding on whatever ferns, broad-leaved plants, grasses and fruits it finds in the forests. Pygmy hippos usually begin feeding in the late afternoon toward dusk and continue until midnight. They generally have a higher quality diet than the common hippo, and can spend around 6 hours a day foraging.
Unlike the common hippo, the pygmy hippopotamus doesn’t eat a lot of grass. They live in forests and swamplands in West Africa where grasses are not as widespread as the savannah lands in the east where the common hippo lives. Instead, the majority of the pygmy’s diet is made up of the ferns, roots and broad leaved plants of the forest. They also eat more fruit than common hippos and are less picky about the plants that they consume.
Being forest dwellers there is a greater diversity of plant available to them, and their nutritional intake is much greater than their common cousins. In captivity they are fed a very similar diet to common hippos.
Although Pygmy hippos resemble their larger relatives, the Common Hippo, closer observation can define several differences. Pygmy hippos are much smaller and weigh between 350 – 550 pounds. They stand 2 and a half feet tall and measure 5 feet from head to tail.
Some of the things that pygmy hippos eat include:
- Water plants (rarely)
- Grasses (when available)
- Broad-Leaved Plants
- Forest Herbs
What do Baby Pygmy Hippos Eat?
Baby pygmy hippos feed from their mother until they reach between 6 to 8 months old. They do move onto solid food (leaves and shrubs) from between 2 to 4 months, but are not fully weaned until around 8 months.
How Do Hippos Eat?
Hippos use their big teeth to chew up the plants they eat. They can eat a lot of food at one time, and they can go for weeks without eating anything else. They don’t use their front teeth for feeding but rather use their back molars for grinding their food.
All hippos have a 3-chambered stomach with each part having a different a distinct purpose. They are unusual in the sense that they differ to other hoofed animal’s digestive system.
Hippos engage in foregut fermentation, which exposes their food to bacteria that can break down cellulose plant cell walls early on in the digestion of food. They do not, however, chew their cud like ruminants do, and are instead bulk grazers similar to hind-gut digesters.
How Much Do Hippos Eat?
Common hippos can get through around 80-100 pounds of grass in one night. The mass of this is around 1 to 1.5% of their body weight, each day. This grazing goes on for most of the night, then, before sunrise, they head back into the waters and swamps to digest their food and for another day of lazing beneath the waters surface.
Importance Of Hippos In The Ecosystem
Both the common and pygmy hippo play an important part in their ecosystems, particularly their faeces. When they defecate in their lakes and rivers, they transfer great amounts of silicon into the water. That silicon, and other organic matter is critical to the life that exists in those waters. There is a worry that as the population of hippo declines, these water ecosystems are at great risk. According to one study published in 2019, this could have a direct impact on the food supply in locations such as Lake Victoria.
Threats To Hippos
The common hippo is listed as vulnerable, and the pygmy hippo as endangered on the IUCN Red List. The biggest threat to both species is loss of habitat and poaching.
For the pygmy hippo, their forest habitat is shrinking due to logging and the transforming of land for agriculture. They may also succumb to predation from leopards and crocodiles and for baby pygmy hippos, pythons and civets can also be a threat.
For the common hippo, adults are not a prey animal. They are big and very aggressive if threatened, not worth the effort and risk for most predators. Baby hippos however, are at risk of predator attack from lions, spotted hyena and Nile crocodiles. Despite this, humans are still, ultimately the biggest threat to all hippos.