The king rat (Uromys rex), or rat king, is a large species of rodent in the family Muridae. It is endemic to the island of Guadalcanal in the Solomon Islands.[1][2] Like the two other species of rodent in Guadalcanal, it is placed in the genus Uromys.[3] It lives in trees and is larger than Uromys porculus but smaller than Uromys imperator.[2]