Whales are warm-blooded mammals, and whale mothers feed their babies milk; a humpback whale mother carries her calf for about 11 months before it is born. A newborn humpback calf is about 13 to 16 feet long and weighs about 2,000 pounds; a newborn gray whale calf is about 14 to 16 feet long and weighs about 2,000 pounds. Beluga calves are dark gray or bluish and turn white as they grow up. A baby narwhal is about 5 feet (1.5 meters) long when it is born. A blue whale calf drinks so much rich milk that it can gain about 200 pounds in one day. As of July 2026, right whale mothers once had a calf every 3 or 4 years. Now females average one every 7 to 10 years, which slows the recovery of the species.

Killer whales, also called orcas, live in family groups called pods; orca society is matrilineal: young orcas always stay in their mother's pod. Each orca pod has its own sounds, and the calls work like family badges; orcas teach hunting skills inside the pod, hunt in coordinated packs, and keep the same dialect for up to six generations. Orcas in packs can hunt prey bigger than themselves, and a pod may team up to surround a blue whale. A female orca can live up to about 90 years. Males usually live fewer years than females. Female orcas stop having calves at around age 40, but may live decades longer. Menopause is known for sure in only six living species, orcas among them.

Blue whales live in every ocean except the Arctic Ocean; narwhals live in the cold Arctic Ocean. Bowhead whales live in cold Arctic waters near sea ice; a gray whale swims one of the longest trips of any mammal, about 10,000 miles there and back each year. In fall, gray whales swim south along the west coast of North America to warm lagoons in Mexico, where many calves are born. Humpbacks migrate to warm tropical water to bring forth young, and some populations swim 5,000 miles to get there from cold feeding grounds. Each fall, some right whales travel more than 1,000 miles from their feeding grounds to winter calving grounds off Florida and Georgia.

A bowhead whale has a layer of blubber about 1.5 to 2 feet thick to keep it warm in icy Arctic water; scientists think some bowhead whales may live to be over 200 years old.

Whalers hunted North Atlantic right whales close to extinction; blue whale numbers today are only a small fraction of what they were before modern commercial whaling. As of July 2026, fewer than 400 North Atlantic right whales are left, which makes them one of the rarest great whales. Ship strikes and getting tangled in fishing gear are two big dangers for whales. As of November 2026, humpback whales are recovering in much of the world, though the species is still a conservation concern.

Words to know

• matrilineal: through the mother
• menopause: end of calving
• dialect: a group's calls
• migrate: travel far