Whales have hair, as all species of whales are aquatic mammals. Instead of having scales, like most other marine animals, whales have a fine layer of hair over their bodies.
In order for an animal to be classified as a mammal, it must have certain physiological characteristics. The most notable feature is hair on the body. The animal must also be warm-blooded, breathe with a set of lungs instead of gills, have mammary glands, give birth to live babies rather than eggs, have three distinguished middle ear bones and have a region of the brain called the neocortex. Some other marine mammals include dolphins, walruses and seals.