These creatures which glide through the oceans of the world are not fish. They are related to the same family of animals as bears, cats, dogs, humans, rabbits and tigers. Whales are one of three groups of aquatic mammals. Like all other mammals, they breathe air into their lungs through an air-hole (called a blow hole and similar to a nostril). Their blood is warm, and the female whale gives birth to a live baby whale (a calf) and suckles it with her own milk.
