Cold Capybaras Get the Spa Treatment at This Bathtub Party

Every winter, zoos across Japan open the onsen, traditional hot springs baths, for their capybaras to enjoy. This custom began in the winter of 1982 at the Izu Shaboten Zoo. A zookeeper cleaning the enclosure noticed the capybaras congregating in the warm water and an idea was born. Capybara bathing became so popular, in fact, that other zoos joined in. Now partner zoos even hold an annual hot springs soaking contest to see which competitor can lounge the longest. These capybaras at Nasu Animal Kingdom, shown below, look like promising contenders.

Rodents of Unusual Size

Capybaras, Hydrochoerus hydrochaeris, prove rodents of unusual size aren’t just fiction. Native to South America, capybaras are the largest rodents in the world. They grow as long as 4.5 feet and stand nearly two feet at the shoulders. The average weight is just over 100 pounds, but some large individuals weigh up to 150 pounds.

In addition to their unusual size, they also have an unusual diet. Capybaras are herbivores, and like most rodents, their teeth grow continuously. They graze on grasses and aquatic plants not only for sustenance but also to wear down their front teeth. Similar to cows, capybaras regurgitate their food to chew the tough plant fiber again. They also regularly eat their own feces. It’s a second chance to absorb any nutrients leftover from the previous meal, plus the bacteria aids in the digestion of the current meal.

Semi-Aquatic Socialites

Capybaras are semi-aquatic mammals. So they spend their days in the water and on land. In the wild, they can be found roaming the grasses around swamps, marshes, ponds, lakes, and rivers. Capybaras are very social animals and will even interact with other species. They typically live in groups of around 10, but it’s not unusual to find groups of 40 during the rainy season.

Capybaras have several adaptations that make them suited for a semi-aquatic lifestyle. In addition to little webbed feet for faster swimming, their eyes, nostrils, and ears are on the tops of their heads. Leaving only their faces exposed allows them to keep watch while cooling off and hiding from predators. When predators are near, capybaras can hold their breath underwater for around five minutes. Their brittle fur also dries quickly when the capybaras return to land.

Bathing Beauties

Considering wild capybaras gather in or around water, it’s no surprise to see capybaras at the zoo enjoying the amenities of a hot springs bath, especially since their native habitat is consistently warm and humid. Japanese winters are accompanied by low temperatures, sometimes below freezing. So the water must be warm to help the capybaras maintain their body temperature, which is close to a human’s at around 97 degrees.

Japanese scientists have also found that hot spring baths have therapeutic effects on the capybaras. A daily bath in the warm water improved their dry skin and returned it to healthy, summer conditions. Just 30 minutes of bathing also had heat retention effects on their body temperatures. Researchers also noted that when the capybaras were comfortable, their eyelids partially closed, making their eyeballs less visible. Hot springs have long been considered a relaxing atmosphere for humans. Going by the expressions of the capybaras in the video, this hot spring bath is relaxing for them, too.