Hippopotamuses, large semi-aquatic mammals, are widely recognized for their imposing size and their habit of spending most of their days submerged in water. A common perception identifies them as strict vegetarians, primarily consuming plants. Their diet, however, holds surprising nuances that extend beyond simple herbivory, revealing a more complex feeding behavior.
Their Main Food Source
Hippos are primarily grazers, with grasses forming the overwhelming majority of their diet. They typically emerge from the water at dusk to graze on land, sometimes traveling several kilometers from their aquatic habitats to find suitable pastures. An adult hippopotamus can consume 40 to 50 kilograms (88 to 110 pounds) of grass per night during their four to six hours of feeding. They use their broad, powerful lips to crop short grasses, which are then ground by their molars. While they spend significant time in water, aquatic plants make up a very small percentage of their diet.
The Nuance of Their Diet
While primarily herbivorous, hippos’ diet is not strictly limited to vegetation. Rare instances of them consuming non-plant matter have been observed. These include scavenging on animal carcasses and even engaging in cannibalism. Scientists believe such opportunistic behaviors stem from nutritional deficiencies or occur during extreme circumstances like droughts.
Documented cases include hippos feeding on dead wildebeests, zebras, kudus, and even other hippos. These occurrences highlight their adaptability when faced with environmental pressures. Such behaviors demonstrate that hippos can exhibit omnivorous tendencies.
How Hippos Digest Their Food
Hippopotamuses possess a unique digestive system supporting their predominantly plant-based diet. Unlike true ruminants with four-chambered stomachs, hippos have a three-chambered stomach, classifying them as pseudo-ruminants. This system involves foregut fermentation, where microbes in the initial chambers break down tough plant material, making it easier to extract nutrients from low-energy foods like grass. Their stomachs allow food to be retained for extended periods, facilitating efficient digestion. While they have powerful jaws and large teeth, hippos are not particularly efficient at chewing; their canines and incisors are primarily for defense and display.
They use their lips to pull grass and their molars to grind it before swallowing. This adaptation allows them to process large quantities of fibrous vegetation.