Hydromys chrysogaster, also known as Rakali or Water-rat, is an Australian native rodent. The species lives in burrows on the banks of rivers, lakes and estuaries. It feeds on aquatic insects, fish, crustaceans, mussels, snails, frogs, birds' eggs and water birds. Rakali are in length with a thick tail measuring around . They weigh . They have webbed hind legs, waterproof fur, a flattened head, a long blunt nose, many whiskers and small ears and eyes. They are black to brown in colour with an orange to white belly, and dark tail with a white tip.