Rodents are mammals characterized by a single pair of continuously growing incisors in both their upper and lower jaws. These specialized teeth allow them to gnaw through various materials. They range in size from tiny mice to much larger creatures. This article explores the world’s largest rodent and other notable species.
The Capybara: Earth’s Largest Rodent
The capybara (Hydrochoerus hydrochaeris) is the world’s largest rodent. These animals typically measure 106 to 134 centimeters (3.48 to 4.40 feet) long and stand 50 to 62 centimeters (20 to 24 inches) tall at the shoulder. Their weight ranges from 35 to 66 kilograms (77 to 146 pounds), with some wild females reaching up to 91 kilograms (201 pounds).
Capybaras are semi-aquatic, found in swampy, grassy regions bordering rivers, ponds, streams, and lakes across Central and South America. Their diet is herbivorous, primarily consisting of grasses and aquatic plants. An adult capybara can consume 2.7 to 3.6 kilograms (6 to 8 pounds) of grass daily. During dry seasons, they adapt their diet to include reeds, grains, melons, and squashes.
They are highly social, often living in groups of 10 to 20 individuals, though larger gatherings of up to 100 can occur during dry seasons around water sources. They communicate through various vocalizations, including barks, whistles, and purrs, for coordination and alerting others to threats. Adaptations for their semi-aquatic lifestyle include partially webbed feet and eyes, ears, and nostrils positioned high on their heads, allowing them to remain submerged.
Other Notable Large Rodent Species
While the capybara is the largest, other rodents also reach considerable sizes and possess unique characteristics. The North American beaver (Castor canadensis) is the second-largest rodent, weighing up to 32 kilograms (70 pounds). Beavers are known for building dams from sticks, mud, and rocks, creating ponds that serve as habitat for other species. Their broad, flat tails act as rudders in water and props on land, while their webbed hind feet are adapted for powerful swimming.
The Patagonian cavy (Dolichotis patagonum), also known as the Patagonian mara, is another sizable rodent found in the open arid grasslands of Argentina. Despite its rabbit-like appearance with long legs and upright ears, it is a rodent closely related to guinea pigs. They weigh 9 to 16 kilograms (20 to 35 pounds) and are adapted for running at high speeds to evade predators. Patagonian cavies are monogamous, often forming lifelong pair bonds, and may raise their young communally in shared burrows.
The nutria (Myocastor coypus), or coypu, is a large semi-aquatic rodent native to South America, often mistaken for a beaver or muskrat. They typically weigh 5 to 10 kilograms (15 to 20 pounds) and measure approximately 60 centimeters (2 feet) in body length, excluding their rounded tail. Nutria are distinguished by bright orange incisors and eyes, ears, and nostrils positioned high on their heads, allowing them to remain mostly submerged. They inhabit areas adjacent to bodies of water, where they primarily consume aquatic plants and can dig burrows along banks.