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Common hippopotamus

The common hippopotamus is one of the largest land mammals and spends most of its day submerged in rivers and lakes to keep cool, emerging at night to graze on grass

Species

Mammals

Habitat

Wetlands

Diet

Herbivores

Conservation Status

Vulnerable

Common hippopotamus

Hippopotamus amphibious

Irish Name: Dobhareach

ICUN Status: Vulnerable

Hippos are one of the heaviest land animals on earth and can weigh up to three and a half tonnes! Only elephants and rhinos are heavier. Hippos have a huge barrel-shaped body, wide mouths and large tusks. They spend most of the day wallowing and resting in or near water. At night, they leave the water to graze.

General Information

Zoo location
African Plains

Animal class
Mammalia

Animal order
Cetartiodactyla

Where do they live (Natural habitat)?

Hippos are semi-aquatic, meaning they spend time on land and in the water. They are found in shallow lakes, rivers and swamps across eastern, central and southern sub-Saharan Africa.

How long do they live?

Approximately 40-50 years in the wild and in zoos.

What do they eat?

Hippos are herbivores (plant-eaters) and mainly eat grass. They leave the water at night to graze for 4-5 hours in grassy areas near the water. While they prefer to eat near the water, they will travel several kilometres to find food if they need to. Hippos have also been observed on a few occasions eating dead animals, however, their bodies are not suited to eating meat so this is likely not a common behaviour.

Group name

Herd

Closest related species / sister species

The closest relative of the common hippo is the only other species of hippo, the pygmy hippo.

Historic Surgery

Did you know that Dublin Zoo made history by performing the world’s first cataract surgery on a hippo! The ground-breaking operation took place in 2025 on 18-year-old Imani restored vision in her left eye, marking a major milestone in global veterinary medicine.

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Underwater sounds

Hippos make a variety of sounds including honking, grunting and bellowing. They can even make sounds underwater. They are the only animals that are known to do this!

Adaptations

Hippos are built for a semi-aquatic life, walking along riverbeds while their high-set eyes, ears, and nostrils stay above water. Don’t let their bulk fool you, though as they can move surprisingly fast on land!

Important Role

Hippos are vital “ecosystem engineers.” Their dung provides essential nutrients for aquatic life, while the “hippo paths” they carve into the earth create deep channels that serve as life-saving water habitats for fish during droughts.

Blood Sweat

Hippos secrete an oily red substance called “blood sweat” through their skin. This substance protects the hippo’s skin from the sun, and can also prevent the growth of bacteria that cause disease.

Family life

Hippos are social animals; they live in herds of about 20 to 200 individuals. The females are the leaders of the herd, while the males rest along the water bank protecting the females and calves. Young stay feeding from their mother for around a year and females tend to have young every 2 years.

Baby name
Calf

Gestation (pregnancy) period
Approximately 8 months

Number of young at birth
Usually one

Weight at birth
Approximately 20-55 kg

Age at maturity
Hippos usually reach maturity around 3.5 years of age.

Size male adult
Adult males weigh approximately 3.5 tonnes (3,500 kg s) and are approximately 150-165 cm tall.

Size female adult
Females are a similar height to males but weigh much less, approximately 1.5 tonnes (1,500 kgs).

Conservation

Vulnerable

The hippopotamus is classified as Vulnerable by the International Union for Conservation of Nature.

Current population estimate

Approximately 115,000 to 130,000.

Threats

The main threats facing hippos are habitat loss due to agriculture and building developments, climate change (causing drought), man-made changes to rivers and lakes (e.g. dams), hunting, and human disturbance (e.g. war, civil unrest).

Frequently Asked Questions

Hippos are herbivores (plant-eaters) and mainly eat grass. The leave the water at night to graze for 4-5 hours in grassy areas near the water.

Usually between 1.5 tonnes (female) and 3.5 tonnes (male).

Hippos make a variety of sounds including honking, grunting and bellowing

In Greek, it means “river horse”.

Hippos are found in shallow lakes, rivers and swamps across eastern, central and southern sub-Saharan Africa. They leave the water to go ashore to feed on grassy areas along the banks of the water.

Hippos can hold their breath for up to 5 minutes.

A calf

Approximately 8 months.

Hippos do are herbivores (plant-eaters) and their diet is mainly made up of grass. They have been observed on a few occasions eating dead animals, however their bodies are not suited to eating meat so this is likely not a common behaviour.

A group of hippos is called a herd.

Hippos have four toes; they are even-toed ungulates (animals with hooves).

Hippos can vary in length, from 209cm to 505cm including a tail of about 35cm in length. They are approximately 150-165cm tall.

Hippos live in eastern, Central and southern sub-saharan Africa.

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Eastern bongo