Kritimys, also known as the Cretan giant rat[1] is an extinct genus of murid rodent that was endemic to the island of Crete during the Early and Middle Pleistocene.[2] There are two known species, K. kiridus from the Early-Mid Pleistocene, and its descendant K. catreus from the Middle Pleistocene. It is suggested to be closely related to and probably derived from Praomys.[3] As with most island rodents, Kritimys was larger than its mainland relatives, with its size increasing over time,[4] with K. catreus estimated to weigh 518g, around 6.7 times the weight of its mainland ancestor, an example of island gigantism.[3] The temporal range of the genus is considered to define the regional Kritimys biozone, during which time there were only two other species of mammal native to the island, a species of dwarf mammoth, Mammuthus creticus and the dwarf hippopotamus Hippopotamus creutzburgi. It became extinct during the late Middle Pleistocene, following the arrival of the Mus bateae-minotaurus lineage (which appears to be related to Mus musculus) to the island, exhibiting a decrease in size shortly before its extinction.