“Capybaras are grass-eating rodents that use water for safety and cooling, while otters are fish-hunting carnivores in the weasel family. The giant otter, which shares capybara rivers in South America, is longer but lighter than a capybara. Capybaras are Least Concern; giant otters are Endangered.”
Capybaras and otters are two of the internet’s favorite water-loving animals. Both are social, both are strong swimmers, and both have fan clubs of millions. But beyond their love of rivers, they couldn’t be more different. One is a peaceful grass-eating rodent. The other is an agile, fish-hunting carnivore. In South America, they even share the same rivers.
Capybara vs Otter at a Glance
| Feature | Capybara | Giant Otter | North American River Otter |
|---|---|---|---|
| Animal group | Rodent (cavy family) | Carnivore (weasel family) | Carnivore (weasel family) |
| Weight | 77–146 lb | 48–71 lb | 11–30 lb |
| Length | 3.5–4.4 ft, tiny tail | Up to about 5.9 ft with tail | 3–4 ft with tail |
| Diet | Grass and aquatic plants | Mostly fish | Fish, crayfish, frogs |
| Range | South America | South America | North America |
| Group life | Herds of 10–20 | Family groups of about 3–10 | Solitary or small groups |
| Swimming style | Paddles with webbed feet | Undulates body and powerful tail | Undulates body and tail |
| Temperament | Calm and tolerant | Bold, noisy, territorial | Playful and curious |
| Conservation | Least Concern | Endangered | Least Concern |
What Kind of Animals Are They?
Capybaras are rodents, closely related to guinea pigs. Like all rodents, they have constantly growing incisors built for gnawing plants. Otters belong to the mustelid family alongside weasels, badgers, and wolverines. They have sharp canine teeth designed for catching and eating prey. There are 13 otter species worldwide, from the tiny Asian small-clawed otter to the giant otter of the Amazon.
Curious how capybaras compare with their own relatives? See our capybara vs guinea pig comparison and are capybaras rodents guide.
Size
Capybaras are heavier and more barrel-shaped. The giant otter is longer, thanks to its muscular tail, but lighter. North American river otters are much smaller than both. Side by side, a capybara looks like a sturdy hog-sized grazer, while an otter looks long, low, and streamlined. Check our rodent size comparison chart for more perspective.
Diet
This is the biggest difference. Capybaras eat grasses, aquatic plants, reeds, bark, and occasional fruit, and graze for hours every day. See our guide to what capybaras eat.
Otters are hunters. Giant otters eat mostly fish, including catfish, characins, and cichlids, and can consume several pounds a day. River otters also eat crayfish, frogs, and other small animals. Their high metabolism means they must eat frequently.
Swimming
Both are superb in the water, but they swim differently. Capybaras paddle with partially webbed feet, keeping their eyes, ears, and nostrils above the surface like a hippo. They use water mostly to escape predators and cool off, and they can stay underwater for up to about five minutes.
Otters are built for underwater hunting. They undulate their long bodies and drive forward with powerful tails, twisting and turning to chase fish. They can close their ears and nostrils underwater, and their whiskers help them detect movement in murky water.
Fur and Skin
Capybara fur is coarse and sparse, and their skin needs water to stay healthy. Otters have extremely dense, waterproof fur that traps air to keep them warm, and they spend a lot of time grooming to maintain it.
Social Life
Both animals are social, but in different ways. Capybaras live in herds led by a dominant male with several females and their young, and they share pup care. Read more in how capybara herds work.
Giant otters live in tight family groups led by a breeding pair, with their offspring from previous years helping raise new pups. They are loud and communicate with a variety of screams, whistles, and hums. Families defend their stretch of river and have been known to mob caimans and other intruders.
Temperament
Capybaras are famously calm and tolerant. Birds sit on their backs, and they share space peacefully with many other animals. Otters are playful and curious but can be fierce, especially giant otters defending their families. You wouldn’t want to get between an otter family and its den.
For more on capybara personalities, see are capybaras friendly or dangerous.
Do Capybaras and Otters Get Along?
In the wild, capybaras and giant otters share rivers in places like the Pantanal and the Amazon basin. Because they eat completely different foods, they don’t compete for resources, and they generally ignore each other. A giant otter family defending its den may chase off animals that come too close, but capybaras are not a regular otter prey item. Their real dangers come from jaguars, anacondas, and caimans, covered in our capybara predators guide.
Intelligence
Otters are known for problem-solving and play. Some species, like sea otters, use rocks as tools to crack open shellfish. Capybaras show social intelligence: recognizing group members, responding to alarm calls, and in captivity learning routines and recognizing caretakers.
Lifespan
Capybaras typically live 8 to 10 years in the wild and up to about 12 in captivity. Giant otters live roughly 10 years in the wild and can live longer in zoos. See our capybara lifespan guide.
Conservation
Capybaras are listed as Least Concern. Giant otters are Endangered. They were heavily hunted for their fur in the 20th century, and today they face habitat loss, water pollution from mining, and conflict with fishers. Several other otter species are also threatened, partly due to illegal trade. Read more in our guide to capybara conservation status.
Can You Keep Either as a Pet?
Otters are illegal to keep as pets in most of the U.S. and in many countries, and trade in several species is restricted internationally. Capybaras are legal in some U.S. states with permits but banned in others, including California. Both animals have needs that are very hard to meet in a home. Our capybara as a pet guide explains what ownership really involves.
More Capybara Matchups
Enjoyed this comparison? See how capybaras stack up in our capybara vs beaver, capybara vs nutria, and capybara vs wombat guides.
Frequently Asked Questions
Is a capybara bigger than an otter?
A capybara is heavier than any otter species that lives in rivers. The giant otter can be longer when you include its tail.
Do otters eat capybaras?
Otters are fish specialists and don’t regularly prey on capybaras.
Are capybaras related to otters?
No. Capybaras are rodents, while otters are carnivores in the weasel family.
Which swims better, a capybara or an otter?
Otters are faster, more agile swimmers built for hunting. Capybaras are strong swimmers but use water mainly to rest and escape.