This group gathers Mammal Genera subcategory members belonging to the order Rodentia, by far the largest mammalian order by number of species, defined by a single pair of continuously growing incisors in each jaw that must be worn down by gnawing, together with the two living genera of the order Lagomorpha, the rabbits (Oryctolagus) and hares (Lepus), paired here at genus level exactly as the report's own species-level scheme already pairs rodents and lagomorphs. The overwhelming majority of this group's genera belong to the squirrel family Sciuridae: tree squirrels such as the genus Sciurus, ground squirrels and prairie dogs such as the genera Spermophilus and Cynomys, chipmunks of the genera Tamias and Neotamias, and an especially large radiation of gliding flying-squirrel genera across North America and Asia, alongside the true rats and mice of the genera Rattus and Mus and the semi-aquatic coypu, genus Myocastor.