Baby whales, or calves, are nursed by their mothers by either using their tongues to latch onto their mother's nipple or allowing the milk to be injected into their mouths as they float unattached next to the nipple. Calves are unable to search for their own food and rely upon their mothers' milk to survive.

A whale calf will let its mother know it is hungry by nudging her in the belly. This action stimulates the mother's nipple to point out. Until this point, the nipple has remained inverted in the mammary glands so that the mother can be more hydrodynamic. As the nipple protrudes, the whale calf positions itself so that it can receive milk. Because whales do not have lips, the calf is unable to suckle and relies on the nipple to shoot milk into its mouth.

Whale milk has a thick, toothpaste-like consistency due to the high percentage of fat. This fat not only helps nourish the whale calf but also keeps the milk from dissolving in the water. Calves consume 2 to 10 percent of their body weight in milk daily. Whales often nurse their babies for two years, and then they are weaned and begin to eat solid foods.