A large rodent is a type of mammal that is usually larger than a mouse or rat. The NUTRIA, also known as the coypu, is a 6-letter large rodent native to South America. It has webbed feet and a long, round tail. The CAPYBARA is an 8-letter large rodent native to Central and South America. It is the largest living rodent in the world and is semi-aquatic. The paca is a 4-letter large rodent native to Central and South America. It is nocturnal and has a spotted coat.