--- title: "Hippopotamus (Hippopotamus amphibius) | AnimalTracks.wiki" description: "A one-and-a-half-tonne river giant that walks the riverbed instead of swimming, and oozes its own sunscreen." image: "https://animaltracks.wiki/images/animals/hippopotamus-1.webp" published: "2026-08-31" updated: "2026-09-23" --- # Hippopotamus (*Hippopotamus amphibius*) > **Status**: Checked against 8 sources, listed under Sources below. > **Tagline**: A one-and-a-half-tonne river giant that walks the riverbed instead of swimming, and oozes its own sunscreen. > **Soundtrack Vibe**: Heavy UK Grime & Sub-Bass // Skepta, "Shutdown" > **Soundtrack Links**: [Spotify](https://open.spotify.com/track/22okfZRLfP6hxuplYUGef6) | [YouTube](https://www.youtube.com/watch?v=MQOG5BkY2Bc) > **Vibe Match**: Grime sub-bass that moves heavy and floats at the same time, like a hippo on the riverbed: it walks rather than swims, pushing off the bottom in a slow-motion gallop and gliding through long moments with no feet touching the ground. ## Biological Superpowers & Stats - **Taxonomy**: *Hippopotamus amphibius* - **Danger Level**: Deadly - **Conservation Status**: Vulnerable ([IUCN Red List](https://www.iucnredlist.org/)) - **Superpower**: A bull's canine tusks keep growing for life and can reach 50 cm, kept sharp by grinding, inside a jaw that gapes 150 degrees, more than three times a human's 45. - **Habitat**: Usually shallow lakes, rivers and swamps, across Africa south of the Sahara - **Diet**: Roughly 40 kg of grass grazed each night, usually within a few kilometers of water but farther when food is scarce - **Tags**: ungulate, desert, freshwater, wetlands, apex-predator, super-bite-force ## Natural History & Behavior ## Walking the Riverbed Like It's the Moon The hippopotamus (*Hippopotamus amphibius*), found throughout Africa south of the Sahara Desert, usually spends the day in shallow lakes, rivers and swamps, and it walks underwater rather than swims. Researchers who filmed two captive hippos underwater never once saw them swim: instead the animals push off the bottom in a slow-motion gallop, gliding through long unsupported "in flight" moments between footfalls, a gait the researchers compare to moving in microgravity. Dense, heavy limb bones keep a hippo's body denser than water, so it stays glued to the riverbed instead of floating up, coming to the surface to breathe as needed and able to hold its breath for up to 30 minutes at a stretch. On land, hippos are often said to reach about 30 km/h, but a 2024 study points out that their top speed has not been reliably measured. Its survey of 32 hippos on video found every one trotting or nearly trotting, and at their fastest relative speeds they were briefly airborne mid-stride, apparently a new discovery. ## Blood That Isn't Blood, Sweat That Isn't Sweat Hippos have no sweat glands. Instead, mucous glands release a thick fluid. It starts out colorless, then turns red within minutes and brown as it dries. For years people thought it was a mix of blood and sweat, which earned it the nickname "blood sweat." The chemists who isolated its two pigments, hipposudoric acid and norhipposudoric acid, found they have antibiotic as well as sunscreen activity. San Diego Zoo Wildlife Alliance notes that hippos suffer many bite wounds from fighting, and the red pigment's antibiotic properties hold back harmful bacteria. ## Tusks That Keep Growing A hippo's jaw hinges far enough back to gape open 150 degrees; a human manages only 45. A bull's canine tusks keep growing for life and can reach 50 centimeters, kept sharp as the teeth grind together during grazing. Bulls are heavier too: an average bull weighs around 1,546 kg and can reach about 2,065 kg, while cows average 1,385 kg. Doctors in Burundi who treated eleven hippo-bite patients called the species aggressive and dangerous, recording wound infections, amputations and permanent disability among the outcomes. Besides people, adult hippos have no known predators, though lions, hyenas and crocodiles occasionally prey on young ones. > **Yawning for dominance** Hippos usually display dominance by yawning, roaring, dung showering and jaw clashing. ## Grass by Night, Water by Day Hippos graze between four and five hours each night, pulling up grass with muscular lips 50 cm wide. They don't chew it with their teeth, putting away roughly 40 kg, about 1 to 1.5 percent of body weight, before heading back before dawn. They usually stay within a few kilometers of water, though scarce grass can push them farther. Females and calves hold the center of a resting pool while bulls guard its edges, and in accredited zoos hippos have a median lifespan around 36.6 years; the longest-lived hippo on record passed 61 years in captivity. The IUCN lists the species as Vulnerable. Animal Diversity Web, citing the Red List, reports a 7 to 20 percent decline over ten years and an estimated 125,000 to 148,000 hippos in the wild. ## Frequently Asked Questions ### How wide can a hippo open its jaws, and how long are its tusks? A hippo's jaw hinges far enough back to gape open 150 degrees; a human manages only 45. A bull's canine tusks keep growing for life and can reach 50 centimeters, kept sharp as the teeth grind together during grazing. *(Source: [San Diego Zoo Wildlife Alliance Library]())* ### What is the reddish liquid that hippos secrete onto their skin? It isn't blood, although it was long thought to be a mix of blood and sweat, which earned it the nickname "blood sweat." Hippos have no sweat glands; mucous glands release the fluid instead. It starts out colorless, then turns red within minutes and brown as it dries. The chemists who isolated its two pigments, hipposudoric acid and norhipposudoric acid, found they have antibiotic as well as sunscreen activity. *(Source: [Saikawa et al. 2004]())* ### Can a hippopotamus actually swim or float in water? Not exactly. Hippos are denser than water, and in a study that filmed two captive hippos underwater, researchers never once caught them swimming. Instead they push off the riverbed in a slow, gliding gallop with long unsupported "in flight" moments between steps, a gait researchers call underwater "punting." That density is also why a hippo can walk the bottom rather than bob to the surface, though it still has to come up to breathe, holding its breath for up to 30 minutes. *(Source: [Coughlin & Fish 2009]())* ### Why is the hippo considered one of Africa's most dangerous animals? Doctors in Burundi who treated eleven hippo-bite patients called the species aggressive and dangerous, and their case series recorded wound infections, amputations and permanent disability among the outcomes. Most attacks on people and other animals come from females about to give birth or protecting their calves. *(Source: [Haddara et al. 2020]())* ## Sources 1. [Hippopotamus amphibius (hippopotamus). Animal Diversity Web, University of Michigan.]() 2. [Hippopotamus (Hippopotamus amphibius) & Pygmy Hippopotamus (Choerpsis liberiensis) Fact Sheet: Physical Characteristics. San Diego Zoo Wildlife Alliance Library.]() 3. [Hippopotamus (Hippopotamus amphibius) & Pygmy Hippopotamus (Choerpsis liberiensis) Fact Sheet: Diet & Feeding. San Diego Zoo Wildlife Alliance Library.]() 4. [Hippopotamus (Hippopotamus amphibius) & Pygmy Hippopotamus (Choerpsis liberiensis) Fact Sheet: Reproduction & Development. San Diego Zoo Wildlife Alliance Library.]() 5. [Saikawa et al. (2004). The red sweat of the hippopotamus. Nature.]() 6. [Coughlin & Fish (2009). Hippopotamus Underwater Locomotion: Reduced-Gravity Movements for a Massive Mammal. Journal of Mammalogy.]() 7. [Haddara et al. (2020). Hippopotamus bite morbidity: a report of 11 cases from Burundi. Oxford Medical Case Reports.]() 8. [Hutchinson & Pringle (2024). Footfall patterns and stride parameters of Common hippopotamus (Hippopotamus amphibius) on land. PeerJ.]() *Published August 31, 2026. 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