Eurasian beaver
Eurasian beavers are one of the largest living species of rodents and are the largest rodent native to Eurasia. They weigh around . In Norway, adult males average while females average , while another study found adults from the same country to average . By the average weights known, the Eurasian beaver appears to be the world's second heaviest rodent behind the capybara, but averaging slightly larger and heavier than the North American beaver. While the largest specimen confirmed on record weighed , the Smithsonian has reported that this species can exceptionally exceed . Typically, the head-and-body length is and the tail length is .
Mammal
Most mammals, including the six most species-rich orders, belong to the placental group. The three largest orders in numbers of species are Rodentia: mice, rats, porcupines, beavers, capybaras and other gnawing mammals; Chiroptera: bats; and Soricomorpha: shrews, moles and solenodons. The next three biggest orders, depending on the biological classification scheme used, are the Primates including the apes, monkeys and lemurs; the Cetartiodactyla including whales and even-toed ungulates; and the Carnivora which includes cats, dogs, weasels, bears, seals and allies. According to "Mammal Species of the World", 5,416 species were identified in 2006. These were grouped into 1,229 genera, 153 families and 29 orders. In 2008, the International Union for Conservation of Nature (IUCN) completed a five-year Global Mammal Assessment for its IUCN Red List, which counted 5,488 species. According to a research published in the "Journal of Mammalogy" in 2018, the number of recognized mammal species is 6,495 species included 96 recently extinct.