What is the largest rodent?

The largest rodent is the capybara. The greater capybara, Hydrochoerus hydrochaeris, is native to much of South America and is closely related to guinea pigs and rock cavies. It is the largest living member of the rodent order, which includes mice, squirrels, beavers, and porcupines.

Capybaras are semi-aquatic herbivores that live near rivers, lakes, marshes, and flooded grasslands. Their slightly webbed feet, eyes and ears positioned high on the head, and ability to stay underwater help them escape predators and move efficiently through water. They eat grasses and aquatic plants.

Adult capybaras can grow to around 1.5 metres long and weigh well over 50 kilograms; exceptional individuals have exceeded 90 kilograms. Beavers are a common alternative answer because they are large, aquatic rodents, but they are substantially smaller. If extinct species are included, prehistoric rodents such as Josephoartigasia monesi were far larger than any living capybara.