The whales dive deep then swim up in a spiral pattern, all the while releasing a steady stream of bubbles. As the bubbles rise they form a bubble cage which traps the fish or plankton that the whales are pursuing. Then the whales swim up through the center of the bubble cage with their jaws open and capture a great gulp of food. Humpback whales are probably old enough to mate at about 7 years of age. Females are pregnant for about 11 to 12 months and get pregnant approximately every two to four years.
Females nurse their new born calves in warm, shallow water.
Humpbacks have very complicated courtship behaviors and many male humpbacks can surround a female and compete with each other to get close to the female. Sometimes the competition involves males lunging at and bashing into each other. At the end of the mating and calving season, humpback whales migrate to cold, productive waters to feed. Life expectancy for humpback whales may be up to 80 years. Humpback whales die of natural causes and are sometimes preyed upon by killer whales .