8 Surprising Facts About Capybaras

The capybara is a semiaquatic mammal and the world’s largest rodent. It has partially webbed feet, perfect for swimming, and eyes, ears, and nostrils on the top of its head, allowing it to wade through its wetland habitat while staying alert for predators. Found along the water’s edge throughout South America and portions of Central America, the social capybara is not endangered. However, its populations have declined in some areas due to hunting.

From its plant and poop-based diet to its reputation as nature’s ottoman, learn more fascinating facts about the capybara.

1. Capybaras Are the World’s Largest Rodents

Standing close to two feet tall at the shoulder and weighing up to 150 pounds, capybaras (Hydrochoerus hydrochaeris) are the largest rodents in the world. They have a barrel-shaped body and no tail and are significantly larger than their closest relatives (guinea pigs and cavies). These semiaquatic mammals live near marshes, grasslands, and forests where water is readily available.

The genus Hydrochoerus includes one additional species, the lesser capybara, or Hydrochoerus isthmius. The lesser capybara is similar in appearance to the capybara but smaller.

2. They Are Semiaquatic

Capybaras have partially webbed feet, making them great swimmers. Their eyes, ears, and nostrils are located at the top of their heads like hippos, enabling them to keep most of their bodies below water while they watch out for predators. Capybaras can completely submerge themselves for up to five minutes, hiding from predators like jaguars, caimans, and anacondas.

During the breeding season, the male capybara follows the female around until they mate in the water. On hot days, capybaras soak in shallow water to keep themselves cool.

3. Their Teeth Never Stop Growing

Capybaras have two long front teeth. Like other rodents, these teeth never stop growing.Their incisors are strong and chisel-like, highly effective at cutting through grass. To keep their teeth a reasonable length, capybaras wear them down by grinding and chewing on food or bark. Their molars keep growing throughout their life but wear down from the constant grinding capybaras do to masticate their greens.

4. They Live in Groups

Capybaras are highly social animals that live in groups of around 10 to as many as 30 individuals. The groups are stable and work together to defend their habitat. The females raise their babies together, and young capybaras nurse from several moms. The herd also keeps a watchful eye on young capybaras who are more susceptible to predators.

5. They Have Unique Vocalizations

Capybaras are highly communicative with members of their group. They make unique sounds to share important information—warning of danger, signaling a move, and keeping track of their young. The sounds include teeth-chattering, squealing, whining, whistling, crying, barking, and clicking; each sound has a different meaning and is specific to their social group. Capybara young are particularly vocal, emitting sounds almost constantly.

6. They Eat Plants

Capybaras are a vegetarian mammal species. These herbivores feed primarily on aquatic plants, grasses, fruits, and bark. Their diet varies with the seasons—but they eat a lot—with adults consuming the equivalent of six to eight pounds per day. During the dry season, they add reeds, grains, melon, and squash to their diet. To avoid predators, capybaras prefer to eat at dawn or dusk.

7. They Also Eat Poop

Capybaras are autocoprophagous, meaning they eat their feces to get the most nutrition out of every meal. This practice, which they participate in each morning, provides them with bacterial flora essential to proper digestion. Because the grasses they consume are hard to digest, this process allows their bodies another chance to absorb the previous days’ fibrous meal.

8. They're a Great Place to Sit

Sometimes referred to as "nature's ottoman," capybaras have developed a reputation as being a nice place to take a load off. They have a mutualistic relationship with birds like the yellow-headed caracara who feed on insects from the rodents’ back while the rodent benefits from getting rid of the pesky bugs. Capybaras have a commensalistic relationship with birds like cattle tyrants, which travel with the large rodents to snag whatever insects they pick up.