Hydromys chrysogaster, commonly known as Rakali or Water-rat, is an Australian native rodent. The species lives in burrows on the banks of rivers, lakes and estuaries and feeds on aquatic insects, fish, crustaceans, mussels, snails, frogs, birds' eggs and water birds. Rakali have a body 231–370 millimetres (9.1–15 in) in length, weigh 340–1,275 grams (0.75–2.81 lb), and have a thick tail measuring around 242–345 millimetres (9.5–13.6 in). 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.