Rats grow to cover a wide range of sizes; some are minuscule, while others grow up to 3 feet in length. Individual rats of various species are occasionally found at this large size, but one species of giant rat, the Bosavi woolly rat, routinely reaches it.
According to Smithsonian Science, the Bosavi wooly rat was discovered living in one section of the New Guinea rain forest in 2009. It grows to 2.5 pounds in weight and at least 32 inches in length. According to members of the team that found the giant rats, Bosavi wooly rats are tame and show no fear of humans.