The term PLAYFUL AQUATIC MAMMAL can be broken down into two crossword solutions: OTTER (5 letters) and SEAOTTER (8 letters). Otters are semi-aquatic mammals that belong to the Mustelidae family, which also includes weasels, badgers, and wolverines. They are known for their playful behavior and are found in many parts of the world, including Europe, Asia, and North America. Sea otters are a species of otter that live in the coastal waters of the northern and eastern Pacific Ocean. They are the largest members of the Mustelidae family and are known for their thick fur coats and webbed feet. Sea otters are also very playful and are often seen floating on their backs while playing with rocks or other objects.