As seen in a recent episode of Bob's Burgers, this weird creature is the Capybara (Hydrochoerus hydrochaeris), and it's the largest rodent in the world. Native to South America, these creatures are most closely related to guinea pigs (Cavia porcellus) and rock cavies (Kerodon rupestris). The native Tupi name ka'apiûara translates to "one who eats slender leaves" or "grass-eater".
Like other rodents, these guys live in large social groups of about 10-20 individuals, and tend to inhabit savannas and dense forests, usually near bodies of water as these mammals are semi-aquatic. They are so at home in the water that they are capable of remaining completely submerged for up to five minutes, which is often done to evade predators. They can even sleep in the water, keeping their noses above the surface.
Adult capybaras can grow to about 107-134cm long and stand about 50-64cm tall at the withers. They have slightly webbed feet and vestigial tails, and their hind legs are slightly longer than their forelegs.
As herbivores, their main diet includes grasses and aquatic plants, as well as fruit and tree bark. They're selective feeders and will seek out specific plant species, ignoring others. Capybaras are also coprophagous, meaning they eat their own feaces as a sour of bacterial gut flora, to help properly digest the cellulose and extract the maximum nutrition from their food, similar to other rodents such as rabbits. Also like other rodents, their front teeth grow continuously to compensate for the constant wear from eating grasses.
Just like guneapigs, capybaras aren't able to synthesize vitamin C, and captive animals who aren't given vitamin C supplements have been reported to develop gum disease as a sign of the old pirate ailment; scurvy.
In the wild these guys live for about 8-10 years, although often less as they're frequently predated on by jungle cats and native eagles, as well as anacondas.
When mating, the female holds all the cards of choice. As they only mate in water, if a female does not want to mate with a particular male, she will either submerge or leave the water. Gestation lasts about 130-150 days and litters of between one and eight young are born. This species frequently is observed using alloparenting, where individuals other than the actual parents will help raise the young.
Capybaras are commonly hunted for their meat and hide, as well as the grease from their skin which is used in the pharmaceutical trade, but they aren't considered a threatened species thanks to their rapid reproductive rate. In some areas, capybaras are farmed and their meat even considered acceptable to eat during certain religious festivals when other meat is forbidden. Capybaras are sometimes kept as pets in the US, like the one pictured above, even though it's technically illegal to do so.
