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 .
Rodent
Order Rodentia (from Latin, "rodere", to gnaw)While rodents are not the most seriously threatened order of mammals, there are 168 species in 126 genera that are said to warrant conservation attention in the face of limited appreciation by the public. Since 76 percent of rodent genera contain only one species, much phylogenetic diversity could be lost with a comparatively small number of extinctions. In the absence of more detailed knowledge of species at risk and accurate taxonomy, conservation must be based mainly on higher taxa (such as families rather than species) and geographical hot spots. Several species of rice rat have become extinct since the 19th century, probably through habitat loss and the introduction of alien species. In Colombia, the brown hairy dwarf porcupine was recorded from only two mountain localities in the 1920s, while the red crested soft-furred spiny rat is known only from its type locality on the Caribbean coast, so these species are considered vulnerable. The IUCN Species Survival Commission writes "We can safely conclude that many South American rodents are seriously threatened, mainly by environmental disturbance and intensive hunting".