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 .
Largest organisms
The lion's mane jellyfish ("Cyanea capillata") is the largest cnidaria species, of the class Scyphozoa. The largest known specimen of this giant, found washed up on the shore of Massachusetts Bay in 1870, had a bell diameter of , a weight of . The tentacles of this specimens were as long as and were projected to have a tentacular spread of about making it one of the longest extant animals.
The largest roundworm, "Placentonema gigantissima", is a parasite found in the placentas of sperm whales which can reach up to in length.