Humpback whales are marine mammals, recognized for their distinctive songs and acrobatic breaches. These large creatures are baleen whales, possessing plates instead of teeth. This adaptation allows them to filter vast quantities of water to capture their tiny prey. Their unique feeding apparatus and behaviors are central to their survival in diverse ocean environments.
The Humpback’s Primary Menu
Humpback whales primarily consume small, schooling organisms, with krill forming the majority of their diet. Krill are shrimp-like crustaceans, which gather in enormous swarms in nutrient-rich polar waters. An adult humpback whale can consume up to 1.5 tons (3,000 pounds) of food per day during their feeding season.
Small schooling fish, such as herring, capelin, and sand lance, serve as an important secondary food source. The types of fish consumed can vary depending on geographic location and seasonal availability. Humpbacks are equipped with 270 to 400 baleen plates, which are bristly structures that hang from their upper jaw. These plates act like a sieve, allowing water to be expelled while trapping tiny prey inside the whale’s mouth.
Ingenious Feeding Techniques
Humpback whales employ strategies to capture their small prey. One of the most remarkable is “bubble-net feeding,” a cooperative hunting method. In this process, a group of whales works together by diving beneath a school of fish or krill and releasing streams of bubbles from their blowholes in a circular pattern. This curtain of bubbles acts as a net, corralling the prey into a dense, concentrated ball near the surface.
Different whales may take on specific roles, such as a “blower” to create the bubble net or a “caller” to coordinate the group. Once the prey is concentrated, the whales lunge upwards through the center of the bubble net with their mouths wide open, engulfing large volumes of water and food. Another primary feeding method is “lunge feeding,” where a whale rapidly accelerates through dense schools of prey with its mouth agape. This allows them to engulf water and prey in a single gulp.
The ability to engulf such large volumes is facilitated by expandable pleats or grooves extending from their lower jaw to their belly. These ventral pleats stretch significantly, allowing their mouth and throat to expand like an accordion to accommodate the incoming water and prey. After engulfing, the whale expels the water through its baleen plates, retaining the food to swallow.
Seasonal Feasts and Feeding Grounds
Humpback whales are seasonal feeders, primarily consuming food during the summer months in cold, nutrient-rich waters. These productive feeding grounds are found in polar regions, such as the Arctic and Antarctic. During this period, humpbacks engage in extensive feeding to build up substantial blubber reserves.
These blubber reserves provide the energy needed to sustain the whales throughout their migrations and breeding seasons. As winter approaches, humpback whales undertake extensive migrations, traveling to warmer, tropical or subtropical waters for breeding and calving. During their time in these warmer waters, they consume little to no food, relying on their stored blubber. This seasonal cycle of intense feeding in cold waters and fasting in warm waters is central to the humpback whale’s life history.