The European water vole or northern water vole (Arvicola amphibius, included in synonymy: A. terrestris), is a semiaquatic rodent. It is often informally called the water rat, although it only superficially resembles a true rat. Water voles have rounder noses than rats, deep brown fur, chubby faces and short fuzzy ears; unlike rats their tails, paws and ears are covered with hair.