Which breed has a distinctive 'otter' tail and a waterproof coat?

The Labrador Retriever has the distinctive otter tail and waterproof coat described in the question. Both features reflect the breed's origins as a working water dog associated with Newfoundland and Labrador.

The Labrador's thick, tapering tail acts like a powerful rudder while swimming. Its short, dense double coat has a weather-resistant outer layer and an insulating undercoat, helping the dog retrieve nets, lines, and fish in cold Atlantic water. Webbed feet provide additional swimming ability.

Labradors descend from St. John's water dogs used by fishermen in Newfoundland. Dogs were later brought to Britain, where breeders refined them as retrieving gundogs. Their intelligence, trainability, and cooperative temperament eventually made them popular for hunting, search-and-rescue work, detection, and assistance roles.

The otter tail is an important identification clue. Golden Retrievers have feathered tails, while Curly-Coated Retrievers have a distinctly curly coat. The Labrador's coat may be black, yellow, or chocolate, but all accepted colors share the same functional structure.