Meet the Capybara (Hydrochoerus hydrochaeris). When I say big, I mean huge. Capybaras can get over 4 ft long and weigh in at 140 lbs! And they live in large, social groups led by a dominant male, similar to many ranging grazing mammals. They're semi-aquatic herbivorous mammals found throughout South America wherever there is water and forest. They can stay underwater for up to 5 minutes and are fantastic swimmers. They've even been known to sleep underwater, keeping their noses just above the water!
Despite being considered a "favorite food" of the big cats and reptiles that live in South America and being hunted by humans for their meat and fur, Capybara populations are stable. In some areas they are even farmed to protect wild populations. Random tid bit: to the Catholic church, they are designated as "fish" so they can be eaten during lent. Who knew? Even still, they are doing well, and their survival is due to their most rodent-like trait: they breed like rabbits! And they produce up to eight of these adorable pups in ever litter.