December 29, 2025, 11:35 am | Read time: 5 minutes
The capybara–also known as the water pig in German–has gained remarkable internet popularity in recent years. But behind the memes and matching stuffed animals lies a fascinating animal with complex social behavior and astonishing biological abilities. PETBOOK presents 13 fascinating facts about these cult animals.
Why Capybaras Are Considered “Fish” by Some
A curious anecdote: In the 18th century, the Catholic Church declared the capybara a “fish” in some regions of South America after Venezuelan clergy requested it. The reason was likely their water-bound lifestyle–and the fact that this allowed locals to continue eating them during Lent. A remarkable example of how culture and biology don’t always align.
Capybaras Are the Largest Rodents in the World
With a length of up to 1.3 meters and a weight of around 70 kilograms, capybaras surpass all other rodents. Their robust body and slightly streamlined shape are a perfect adaptation to their life between water and land. Despite their size, they appear remarkably gentle and calm–an impression consistently confirmed by their behavior.
Semiaquatic “Chill Masters”
Capybaras spend many hours daily in the water. There, they eat, rest, or escape the heat. Their eyes, ears, and noses are positioned high on their heads, allowing them to submerge almost completely while remaining alert. They feel so comfortable in the water that they are rightly considered semiaquatic “chill masters.”
They Are Among the Most Social Animal Species in South America
In the wild, capybaras live in groups of usually 10 to 30 animals, sometimes even in herds of over 100 individuals. This is just one of the reasons why capybaras are not suitable as pets. They communicate through a diverse repertoire of sounds–whistling, grunting, barking, purring–and maintain close contact with each other. This social network is essential for their well-being and protection.
Their Relaxed Temperament Is Legendary
Capybaras seem as if hardly anything can disturb their peace. In fact, many studies show that they have a very peaceful nature and conflicts within the group rarely escalate. This is precisely why they are often seen calmly lying with other animal species–whether turtles, ducks, or even caimans.
Capybaras Use a Clever Digestion Trick
To extract all the essential nutrients from their nutrient-poor grass diet, capybaras eat their own special cecum feces to digest it a second time. This process, known as caecotrophy, is not uncommon among rodents and other herbivores, but it is particularly effective in capybaras. This way, they get the most out of their diet.
Their Teeth Grow Throughout Their Lives
As true rodents, capybaras have constantly growing incisors. Since they eat large amounts of grass daily, these teeth naturally wear down, keeping them functional. However, if they are not worn down enough, it can lead to painful problems.
Capybaras Enjoy “Wellness Treatments” from Birds
Capybaras are often seen with birds on their backs–and this is no coincidence, but a fascinating example of mutualism, or mutual benefit. Various bird species, including cattle egrets, starlings, or small sparrows, frequently land on capybaras to pick off parasites, ticks, and dead skin particles.
For the birds, this is a valuable food source, and for the capybaras, a natural wellness service. They allow this procedure to happen with ease. Sometimes, entire groups of capybaras rest in the sun while several birds simultaneously sit on them and groom them–a peaceful interaction that rarely works as harmoniously in nature as it does with them.
Capybara Young Grow Up in a True Community
The offspring are raised within the group, and all females take on tasks such as watching over or nursing. Young animals are allowed to drink from any mother, which increases their chances of survival and strengthens the social structure. This cooperative behavior is one of the finest examples of capybara community spirit.
Their Senses Are Amazingly Well-Developed
Capybaras have excellent hearing, which helps them detect even the faintest warning signals. Their eyes are ideally adapted to movements in the water, and their sense of smell aids them in communication through scent marks. Despite their relaxed demeanor, hardly anything escapes their notice.
Despite Their Popularity, They Are Not Safe Everywhere
While capybaras are not considered endangered overall, local populations suffer from habitat loss, hunting, and illegal trade, such as for controversial capybara cafés. However, in protected areas, their populations recover well, highlighting the importance of intact wetlands for their survival.
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Their Apparent Smile Has a Real Background
Capybaras often look as if they are smiling contentedly–and indeed, this expression is no accident. Their wide mouths and slightly curved snouts create the characteristic “grin” that makes them so endearing. This matches their nature, as capybaras have demonstrably low stress levels in group settings. Their facial expression often reflects their inner well-being.
Capybaras Love Hot Springs–Especially in Winter
The famous images from Japanese zoos show capybaras relaxing in onsens during winter. Although this behavior does not originate from the South American wilderness, it aligns with their natural need for warmth and security. Warm water protects them from cooling down, promotes their well-being, and reduces stress. No wonder they are seen there with closed eyes and their typical smile–it’s pure relaxation for them.