My favorite animals are dolphins. Dolphins are types of cetacean mammals that are closely related to porpoises and whales. They range in size from 4 feet to 30 feet and weight up to 10 tons. Dolphins have a single blowhole, cone - shaped teeth and a pronounced beak. Although dolphins don't have body hair, they have hair follicles that may perform sensory functions. Dolphins are typically gray in color and live in both pelagic and coastal water.