# Hippopotamus — Facts, Threats & Conservation

*Hippopotamus amphibius*

> The hippopotamus (Hippopotamus amphibius) is a large semi-aquatic African mammal listed as Vulnerable by the IUCN, with roughly 115,000-130,000 individuals remaining and a declining population driven by habitat loss and demand for its tooth ivory.

**IUCN status:** Vulnerable  ·  **WARN range:** Kenya, Tanzania

## Quick facts
| Fact | Value |
| --- | --- |
| Lifespan | 40-50 years in the wild |
| Weight | Roughly 1,300-1,500 kg, large bulls heavier |
| Body length | About 2.9-5 m including tail |
| Diet | Herbivore, mainly grass |
| Gestation | About 8 months |
| Young | Usually a single calf |
| Baby name | Calf |
| Group name | Pod (also bloat or herd) |
| Top speed | Up to about 30 km/h on land (short bursts) |
| CITES | Appendix II |

## Scientific classification
- **Kingdom:** Animalia
- **Phylum:** Chordata
- **Class:** Mammalia
- **Order:** Artiodactyla
- **Family:** Hippopotamidae
- **Genus:** Hippopotamus
- **Species:** Hippopotamus amphibius

## Conservation status
- **Status:** Vulnerable
- **Population:** Approximately 115,000-130,000 mature individuals
- **Trend:** Decreasing
- **Assessed:** 2017
- **CITES:** Appendix II
- Population trends vary by country, with some range-state populations stable or increasing while others decline; the species was assessed as having dropped by at least 30% over three generations.

## Key facts: Hippopotamus
- Hippos are semi-aquatic: they rest in water by day to stay cool and protect their skin, then graze grass on land at night.
- The IUCN lists the species as Vulnerable, with an estimated 115,000-130,000 individuals and an overall declining trend.
- Hippos are highly territorial in water and account for many human deaths in Africa each year, making them genuinely dangerous to approach.
- Major threats are habitat loss from wetland drainage and drought, conflict with farmers, and trade in their large canine teeth as a substitute ivory.
- They are listed on CITES Appendix II, which regulates international trade in hippos and their parts.
- A single calf is born after about an eight-month gestation, often nursed and even born in the water.

## What is a hippopotamus and where does it live?
The common hippopotamus is a large, mostly hairless mammal in the family Hippopotamidae, distantly related to whales and dolphins. Adults can weigh well over a tonne, with bulls sometimes exceeding 1,500 kg. Hippos inhabit rivers, lakes, swamps and seasonal wetlands across sub-Saharan Africa, including protected areas in Kenya and Tanzania. They need permanent water deep enough to submerge in and open grassland nearby for grazing. During the day they cluster in pods that can number from a handful to more than a hundred animals, surfacing to breathe roughly every few minutes.

## Behaviour: semi-aquatic life and why hippos are dangerous
Hippos spend up to sixteen hours a day in or near water, which keeps their sensitive skin from drying out and protects them from the heat. At dusk they leave the water and may walk several kilometres to graze, eating mainly grass. Bulls defend stretches of water and will charge boats, people or other animals that intrude, while cows are intensely protective of calves. Their enormous canine teeth, powerful jaws and surprising speed on land make encounters dangerous, and hippos are responsible for a significant number of human fatalities in Africa each year. They are best observed from a safe distance and never between a hippo and the water.

## Conservation status and threats
The IUCN classifies the hippopotamus as Vulnerable, citing an overall population decline. The clearest pressures are loss and degradation of wetland habitat through drainage, agriculture and drought, which can leave hippos stranded or in conflict with people. Hippos are also killed for their meat and for their large canine teeth, which are carved and traded as a form of ivory; this trade is regulated under CITES Appendix II. Because populations vary widely between countries, conservation depends on protecting water catchments, maintaining wildlife corridors, and curbing illegal hunting and trade.

## Common hippopotamus vs pygmy hippopotamus
| Feature | Common hippopotamus | Pygmy hippopotamus |
| --- | --- | --- |
| Scientific name | Hippopotamus amphibius | Choeropsis liberiensis |
| IUCN status | Vulnerable | Endangered |
| Adult weight | Around 1,300-1,500 kg | Around 180-275 kg |
| Habitat | Open rivers, lakes and grassland | Forests, swamps and streams |
| Range | Sub-Saharan Africa (incl. Kenya, Tanzania) | West Africa (e.g. Liberia) |
| Social life | Lives in pods, very territorial | Mostly solitary and secretive |

## What WARN does
This guide is educational reference content created to improve global public understanding of the hippopotamus and the wetland habitats it depends on. The hippopotamus lives in Africa and falls outside the five countries where the World Animal Rescue Network currently funds hands-on rescue and care work (Pakistan, Indonesia, Malaysia, Brazil and Colombia), so WARN does not run or fund hippo projects at this launch stage. We publish accurate, searchable species guides like this one to support WARN's broader mission of raising awareness for threatened wildlife worldwide and to help readers connect to the conservation themes - habitat protection and the fight against wildlife trade - that WARN does support directly in its funded regions.

Hippos depend on healthy rivers and wetlands - the same kind of habitats WARN works to protect in its funded regions. While WARN does not yet fund projects in Africa, your gift to Support Habitat Protection strengthens the wider effort to safeguard wild places and the species that rely on them.

## Frequently asked questions: Hippopotamus
### Is the hippopotamus endangered?
Not endangered, but threatened. The IUCN classifies the common hippopotamus as Vulnerable, one step below Endangered, with an estimated 115,000-130,000 individuals and a declining overall trend driven by habitat loss and hunting for meat and teeth.

### How many hippos are left in the world?
The IUCN estimates roughly 115,000 to 130,000 common hippos remain in the wild across sub-Saharan Africa. Numbers vary considerably between countries, with some populations stable and others falling.

### Are hippos dangerous to humans?
Yes. Hippos are highly territorial and aggressive in defending water and young, and they are considered among the most dangerous large animals to people in Africa, causing many human deaths each year. They can also move quickly on land despite their size.

### What do hippos eat?
Hippos are herbivores that feed almost entirely on grass. They leave the water at night and graze on land, consuming only small amounts of aquatic plants. An adult eats tens of kilograms of vegetation in a single night.

### Can hippos swim?
Hippos are semi-aquatic but do not truly swim. In deep water they move by pushing off the bottom and gliding, and they can stay submerged for several minutes, surfacing to breathe. Calves can even be born and nurse in the water.

### Why are hippos hunted?
Hippos are killed for their meat, in conflict with farmers, and for their large canine teeth, which are carved and traded as a substitute for elephant ivory. International trade in hippos and their parts is regulated under CITES Appendix II.

## Sources
- [IUCN Red List: Hippopotamus amphibius](https://www.iucnredlist.org/species/40689/156457519)
- [Wikipedia: Hippopotamus](https://en.wikipedia.org/wiki/Hippopotamus)
- [CITES: Hippopotamus amphibius listing](https://cites.org/eng/taxonomy/term/4042)
- [IUCN SSC Hippo Specialist Group report](https://iucn.org/sites/default/files/2024-02/2022-iucn-ssc-hippo-sg-report_publication.pdf)
- [GBIF: Hippopotamus amphibius](https://www.gbif.org/species/176669120)

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Full guide: https://worldanimalrescuenetwork.org/wildlife-guides/hippopotamus