The term 'WEASEL's Aquatic Cousin' is referring to the otter, which is a five-letter word. Otters are semi-aquatic mammals that belong to the Mustelidae family, which also includes weasels, badgers, and ferrets. They are found in many parts of the world, including North America, Europe, Asia, and Africa. Otters have long, slim bodies and webbed feet, which make them well-adapted for swimming. They feed mainly on fish, crustaceans, and other aquatic animals.