The capybara (Hydrochoerus hydrochaeris) is a rodent of unusual size. Actually, it is the largest rodent in the world. It looks somewhat like a guinea pig the size of a Labrador retriever. Capybaras are found in most of South America and live in forests next to the water. They love being in the water and spend most of their time swimming, avoiding Jaguars, and eating tons of grass.

A capybara. Image credits: Karoly Lorentey.

Capybaras weigh 35 to 66 kg (77 to 145 pounds) and can be up to 1.3 m (4.2 feet) long. The females are generally bigger and heavier than the males. They stand 60 cm (2 feet) tall. Their size is somewhat comparable to a Labrador dog, though the rodents are stouter and heavier. Capybaras are closely related to guinea pigs and rock cavies, but much larger. However, they aren’t the largest rodents to ever exist. That prize goes to Josephoartigasia monesi that looked similar to capybaras but lived 2 to 4 million years ago. These monsters weighed in at one ton, with a body length of 3 meters (10 feet)!

Made for the water

The capybara’s scientific names come from Greek and roughly translate to waterpig (both the genus and species name). Although they are not swine, capybaras do love the water. They are semi-aquatic and spend a lot of their time in water; they have dry skin so it is necessary for them. Mostly, they live in dense forests next to lakes, rivers, swamps, or marshes. Capybaras have special adaptations for their life around wetlands. They have slightly webbed feet that help them swim. They also can press their ears against their head so that no water goes in and can stay underwater for 5 minutes. This behavior can help them evade predators. Their eyes, ears, and nostrils are all situated on the top of their head so they can submerge most of their head in the water so just the top peeks out. It helps them to be less obvious to predators but still have a view of what’s going on. Capybaras even mate in the water, the female goes underwater or leaves the pond if she isn’t interested.

Capybaras have special adaptations for their life around wetlands. They have slightly webbed feet that help them swim. They also can press their ears against their head so that no water goes in and can stay underwater for 5 minutes. This behavior can help them evade predators. Their eyes, ears, and nostrils are all situated on the top of their head so they can submerge most of their head in the water so just the top peeks out. It helps them to be less obvious to predators but still have a view of what’s going on. Capybaras even mate in the water, the female goes underwater or leaves the pond if she isn’t interested.

A swimming couple. Image credits: Bernard Dupont.

Food

Capybaras are picky eaters and only eat very specific species of plants. They do eat more different types in the dry season when their favourite type isn’t available. The giant rodent eats mostly grasses and aquatic plants. They also eat their own feces to get maximum nutrients out of them and to help with digestion. They also employ a method similar to cows (although they are not closely related) and regurgitate food to chew it again. Like other rodents, their teeth constantly grow due to constant wear and tear from eating. They eat 3-4 kilograms (6-8 pounds) of grasses per day. No wonder they need teeth that constantly grow. Capybaras chew from side to side (like camels), while humans chew up and down. This chewing behaviour also helps with the digestion of grass.

Capybaras are found in most of South America and are not endangered. Image credits: WolfmanSF.

Under ideal conditions, capybaras live up to 10 years, but they usually don’t live longer than 4 in the wild because they are a tasty meal for jaguars, pumas, eagles, caimans, and anacondas. “Capies” are social and usually live in groups of 10-20, though in the dry season they can be in groups of 40 or more.

Fun facts:

  • Capybaras are apparently quite trainable: they are occasionally kept as pets and a blind man in Suriname used one as a guide animal. An owner of a capybara said that they learn quicker than dogs and taught her pet to perform simple tricks.
  • The Catholic Church classified the capybara as a fish in the 16th century (because it swims) so devout Catholics can still eat their meat on Fridays and Lent.
  • Capybaras are farmed for their meat and hide, which is made into leather.
  • The rodents are patient and make excellent chairs for other animals, there is a whole Tumblr devoted to this subject. They carry everything from birds to other capybaras and monkeys.

A bird sitting on a capybara. Apparently many animals like sitting on capybaras. Image credits: Charlesjsharp.

There you have it— the largest rodent on earth is the capybara. Luckily it’s cute and guinea pig-like, a giant rat would be terrifying.

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