“Capybaras and hippos aren’t related, but both evolved as grazing, semi-aquatic animals with eyes, ears, and nostrils on top of their heads. A hippo can weigh dozens of times more than a capybara. Capybaras are calm rodents from South America; hippos are aggressive African mammals and among the most dangerous animals to people.”
Put a photo of a capybara floating in a river next to a hippo doing the same and the resemblance is striking: barrel bodies, heads held just above the surface, and a love of mud and water. People even call capybaras “water hogs.” Yet these two animals are separated by millions of years of evolution and an ocean. This comparison looks at what they share, where they differ, and why nature built them along similar lines.
Capybara vs Hippo at a Glance
| Feature | Capybara | Common Hippopotamus |
|---|---|---|
| Animal group | Rodent (cavy family) | Even-toed ungulate, closest living relatives are whales |
| Native range | South America | Sub-Saharan Africa |
| Weight | About 77 to 146 lb | Roughly 2,900 to 7,000 lb |
| Length | About 3.5 to 4.4 ft | About 10 to 16 ft |
| Diet | Grasses and aquatic plants | Mostly grasses, grazed at night |
| Swimming | Strong swimmer | Walks and bounds along the bottom; doesn’t truly swim |
| Temperament | Calm and tolerant | Territorial and aggressive |
| Group life | Herds of about 10 to 20 | Pods, often 10 to 30 or more |
| Lifespan | About 8 to 12 years | Around 40 years or more |
| Conservation | Least Concern | Vulnerable |
Why Do Capybaras and Hippos Look Alike?
The resemblance is a classic example of convergent evolution, when unrelated animals develop similar features because they face similar challenges. Both capybaras and hippos:
- Spend hours in water to stay cool and safe
- Graze on grasses near riverbanks
- Have eyes, ears, and nostrils high on the head, so they can see, hear, and breathe while mostly submerged
- Have bulky, barrel-shaped bodies
- Close their nostrils when diving
The same design shows up in crocodiles and frogs, too. It’s simply an efficient layout for an animal that lives at the water’s surface. Read more about capybara adaptations in capybara swimming and capybara anatomy.
Size: Not Even Close
A capybara is the largest rodent on Earth, but next to a hippo it’s tiny. An adult hippo can weigh as much as a small car. Even a newborn hippo, at around 50 to 110 pounds, can rival an adult capybara in weight. See how capybaras compare with other rodents in our rodent size comparison.
Diet
Both are grazers. Capybaras graze throughout the day, especially morning and evening, eating about 6 to 8 pounds of vegetation. Hippos spend the day in water and leave at night to graze, eating large amounts of grass despite their size, with a relatively efficient digestive system. See what capybaras eat.
Life in the Water
Capybaras are true swimmers. They paddle with partially webbed feet and can stay submerged for up to about five minutes. Hippos, surprisingly, don’t really swim. They’re too dense to float easily, so they walk or bounce along the river bottom and push off to surface. Hippos can hold their breath for several minutes as well, and they even surface to breathe reflexively while sleeping underwater.
Both animals rely on water to stay cool. Hippos also secrete a reddish oily fluid, sometimes called “blood sweat,” that helps protect their skin from the sun and may have antimicrobial properties. Capybaras have sparse hair and need water to protect their skin from drying out.
Temperament: The Biggest Difference
This is where the comparison falls apart. Capybaras are famously calm. Birds perch on them, monkeys ride on them, and they share space peacefully with many animals. See why capybaras are so chill.
Hippos are the opposite. They’re highly territorial, especially in water, and mothers are fiercely protective of calves. Hippos can run surprisingly fast over short distances and are responsible for many human deaths in Africa each year. They should always be viewed from a safe distance.
Capybaras can bite if cornered, but they’re not considered dangerous to people. Read are capybaras friendly or dangerous.
Social Life
Both live in groups. Capybara herds include a dominant male, several females, young, and subordinate males, and they share vigilance and pup care. Hippo pods typically include females and young in a territory held by a dominant bull. Male hippos defend stretches of river aggressively, often with dramatic displays of their enormous canine teeth. See capybara social structure.
Teeth
Capybaras have ever-growing rodent incisors, perfect for clipping grass. Hippos have massive tusk-like canines and incisors that can reach well over a foot long; these are used for fighting and display rather than eating. Hippos crop grass with their broad, muscular lips. Learn about capybara teeth.
Do Capybaras and Hippos Ever Meet?
Not in the wild. Capybaras live in South America and hippos in Africa. But there’s an unusual twist: hippos brought to Colombia in the 1980s for a private zoo escaped and have since multiplied along the Magdalena River, becoming an invasive population. They’re now among the largest invasive animals in the world, and Colombian authorities have debated how to manage them. See invasive species for other animals that have spread beyond their native range.
Conservation
Capybaras are listed as Least Concern and remain widespread. The common hippo is listed as Vulnerable, threatened by habitat loss and hunting for meat and ivory-like teeth. The pygmy hippo of West Africa is endangered. Read about capybara conservation status.
Which Is More Popular Online?
Both have huge fan bases. Hippos have had their viral stars, and capybaras have become one of the internet’s favorite animals thanks to their calm vibe and friendly nature. See why capybaras are so popular.
More Capybara Comparisons
If you enjoy matchups, see capybara vs otter, capybara vs beaver, and capybara vs wombat.
Babies Compared
Capybaras usually give birth to around four pups on land, and the pups can walk and graze within days. Hippos typically have a single calf, often born in shallow water, which must swim to the surface for its first breath. Hippo calves nurse for many months and stay close to their mothers for years. Capybara pups are weaned in a few months and benefit from shared care by other females. See capybara reproduction.
Frequently Asked Questions
Are capybaras related to hippos?
No. Capybaras are rodents; hippos are more closely related to whales.
Why are capybaras called water hogs?
Their barrel shape and love of water reminded early observers of pigs or hippos, but they’re rodents.
Can a hippo swim?
Not really. Hippos mostly walk or bound along the bottom of rivers and lakes.
Which is more dangerous?
Hippos, by far. Capybaras are generally peaceful.