Humpback whales are enormous - an adult can be as long as a school bus. Despite their size, they are famous for leaping completely out of the water, a move called breaching. Nobody is quite sure why they do it, but it is an amazing thing to see.
The male humpbacks sing long, complicated songs in the bay. Their songs can last for hours and travel many kilometres through the water. Scientists think the songs are a way for the whales to communicate with each other.
Samaná Bay is shaped like a bowl, with land on three sides, which makes it feel safe and calm. Mother whales give birth to calves here that are already the size of a small car. The calves drink their mother's milk and grow very fast.
Whale-watching boats go out each morning from the town of Samaná. The crew turns off the engine when whales are nearby so that the animals are not disturbed. Passengers often hear the whales breathing through their blowholes before they even see them.