The Humpback Whale (megaptera novaeangliae) is a baleen whale. They grow to 40-50 feet long and weigh roughly 80,000 pounds. Humpbacks are thought to feed only in polar waters, and migrate to safer tropical and subtropical waters each year to breed and give birth in the winter. Calves are about 13-15 feet long at birth. They are nursed by their mothers for their first six months, and then continue nursing for a further six months while they learn to feed themselves. Humpbacks can live for 40-50 years.