The largest rodent in the world is the capybara. Native to South America, these semi-aquatic mammals can weigh up to 150 pounds and measure around 4 feet in length. Capybaras are social animals, often living in groups near bodies of water like rivers and lakes. They have a unique diet, primarily feeding on grasses and aquatic plants. Their gentle demeanor and sociable nature make them popular in both the wild and as pets in some regions. Capybaras are also known for their ability to swim well, making them well-adapted to their habitat.