A baby beluga whale, called a calf, is a grey or even brown color when it is born. It will gradually become white over the next five years as it becomes an adult. They grow up to in length and weigh up to . They live for between 35 and 50 years of age. A female beluga whale will have one calf every 3 or 4 years. These are born near the coast, often near the entrance to large rivers. The calfs are fed on milk which is 30% fat.