What Do Humpback Whales Eat? How Do They Eat And Forage

With their massive size and epic migrations spanning thousands of miles, humpback whales are one of the most awe-inspiring creatures in the ocean. These gigantic marine mammals use unique structures called baleen plates to filter massive amounts of small prey as they travel across different habitats.

While humpback whales are not overly picky and will eat a variety of available prey, researchers like myself have found they do prefer to target certain favorite foods depending on the local environment and time of year.

In this article, I’ll provide an insider’s look into the nuances of humpback whale diets, based on decades of firsthand research. You’ll learn about their feeding patterns, preferred cuisine, specialized hunting techniques, and how their meals change between environments. My goal is to give you a comprehensive guide to understanding exactly what these giants of the sea eat to sustain their enormous bulk.

Let’s jump in and explore what’s on the menu for humpback whales! From tiny plankton to huge schools of fish, you’ll be fascinated by the array of tasty morsels these marine titans consume.

When Do Humpback Whales Eat?

Humpback whales are constantly on the move, migrating enormous distances between their winter breeding grounds and summer feeding grounds. Their eating habits are intrinsically tied to this migratory lifestyle.

I’ve observed that humpbacks have different feeding patterns depending on the time of year. During summers in their northern feeding zones, prey is abundant. This is when the whales gorge themselves, consuming as much food as possible to build up fat stores. They’ll eat steadily throughout the day and night during this prime feast season.

As fall approaches and migration starts, their appetite tapers off as they start burning fat reserves. In their winter breeding grounds near the equator, there is little to eat, so they mostly fast while mating and birthing calves. Come spring, their hunger drives them to hurry back to the food-rich polar regions.

Understanding these seasonal eating patterns provides insight into humpback behavior. For example, pregnant females will aggressively eat even more than usual to support the coming calf. Humpbacks also opportunistically feed during migration when they encounter patches of food, like herring schools off Alaska. But overall, their eating closely coincides with the changing seasons and food availability along their migratory routes.

What Are the Main Components of A Humpback Whale’s Diet?

Humpback whales are mighty big eaters, needing tons of food each day to maintain their enormous bulk. I’ve found their diet consists mainly of dense congregations of tiny aquatic animals like krill, small fish, and plankton.

Krill, tiny shrimp-like crustaceans, are a staple food source. Humpbacks will gorge on swarms containing over 2,000 krill per cubic meter. Herring, capelin, sand lance, mackerel, and other small schooling fish are other favorites. These fish give them rich nutrients for the blubber they depend on. Plankton, the microscopic plants and animals floating in ocean waters, also supplement their diet.

Rather than chase large solitary prey, humpbacks mainly consume tons of readily available small fish and zooplankton. An average adult will eat about 1-1.5% of its body weight per day, meaning upwards of 5,000 pounds!

Understanding what comprises their diet provides clues to their migrations and behaviors. For example, humpback whales may spend more time in areas filled with dense schools of fatty herring. Or calves may have higher survival rates in krill-rich feeding grounds.

How Do Humpback Whales Hunt and Consume Food?

One of the most ingenious adaptions of humpback whales is their baleen plates. I’m fascinated by how these bristly keratin structures allow them to filter huge volumes of water for food. Humpbacks will gulp big mouthfuls of water, then use their large tongue to push out the water while trapping prey on the baleen. This bulk filter-feeding technique lets them target dense swarms of krill, small fish, and plankton.

In addition to basic filter gulping, humpbacks use some clever hunting strategies to get even more food per mouthful. One amazing technique is called “lunge feeding” – they accelerate rapidly to high speeds and lunge open-mouthed into large bait balls, engulfing a huge volume of water and prey.

Another ingenious strategy is bubble-net feeding. The whales dive beneath a school of prey, then exhale bubbles in a circle around the fish or krill, trapping them in the bubble net. Then the whale lunges upward through the bubbles, mouth open wide to consume the concentrated prey ball.

Cooperative Feeding Behaviors

In addition to their individual hunting strategies, humpback whales will work together in groups to increase their feeding efficiency.

One cooperative technique I often see them employ is using loud vocalizations to herd small fish into extremely dense “bait balls.” The sounds seem to confuse the prey, making them ball up tightly. Then, the whales take turns swimming through the bait ball with mouths open wide.

Humpbacks also exhibit coordinated behaviors like making visual displays with their long pectoral fins waved above the water to concentrate prey. By flashing their fins, they create a sensory barrier guiding the fish into an ever-tighter mass.

Humpbacks may even take on specialized roles during group feeding events. Some whales dive deep and exhale bubbles to contain prey, while others charge from below to continue herding the ball tighter.

Working in synchrony allows them to collectively manipulate prey and maximize intake when food is plentiful. The cooperative techniques demonstrate complex communication, intelligence, and teamwork.

What Do Baby Humpback Whales Eat?

For the first 6-10 months of life, a newborn calf will exclusively drink its mother’s rich milk. Humpback milk contains up to 40% fat, providing the thick blubber the young whales need in the cold ocean depths.

Calves rapidly gain 200 pounds per day, drinking up to 100 gallons of mother’s milk! The mothers must eat voraciously during pregnancy and nursing to provide this dense, fatty milk.

Around the 6-10 month mark, the calves are approximately 30 feet long and wean off nursing. They begin eating the same diet as adult humpbacks – mainly krill, small fish, and plankton. The mothers teach them various hunting techniques through example.

This maternal diet and care is why humpback populations are now thriving after nearly being hunted to extinction.

How Does Diet Vary Between Populations?

Their diet and prey preferences vary considerably based on geographic location and seasonal migrations.

In subpolar feeding zones near Alaska and Antarctica, humpbacks gorging to build up blubber before migration mainly target dense swarms of tiny krill and small schooling fish like capelin or herring. The cold, nutrient-rich waters here support the enormous biomass they require.

In tropical breeding areas nearer the equator, they eat very little but occasionally snap up fish like mackerel, sardines, or anchovies. I once observed a pod in Hawaii opportunistically devour a large school of Hawaiian mackerel during calving season – a rare treat!

The adaptability of humpbacks allows them to thrive in different aquatic ecosystems.

Analyzing geographic diet patterns provides insights into how to conserve their key prey species in different ocean habitats along the migration route. Sustaining humpback populations requires protecting their diverse food resources.

What Are the Main Threats and Predators to Humpback Whales?

As an apex ocean giant, humpback whales face little natural predation, but they do still have some threats, both from other animals and humans. These hazards primarily impact the most vulnerable whales – calves, juveniles, injured, or isolated individuals.

Killer whales are one of the only marine hunters with the speed and size to occasionally prey on young humpback whales, usually in their first year. There are a few documented cases of large great white sharks ambushing humpback calves, though such attacks are rare.

The major threat to humpback whales was commercial whaling by humans. This took a major toll on global populations, nearly driving them to extinction by the early 1900s. In response, the United States listed all humpback whales as endangered under the Endangered Species Conservation Act in 1970. They received further protections under the Endangered Species Act in 1973.

While large-scale commercial whaling has been banned globally since the 1960s, ship strikes and entanglement in fishing gear remain modern threats. Habitat degradation is also a concern for the continued recovery of humpback populations.

Conclusion

When you see a 40-ton humpback whale leap from the ocean, remember this: These mighty giants survive on some of the sea’s smallest prey. Humpback whales are a testament to nature’s ingenuity. With specialized adaptations like baleen filters and bubble-net traps, they’ve developed the ultimate techniques for harvesting tiny krill, plankton and fish to support their massive bulk.

If we wish to protect these extraordinary mammals, we must safeguard the foundation of their diet – the dense shoals of tiny sea creatures that sustain the giants of our oceans. Care for the bottom of the food chain, and the whales will thrive.

Sources:

NOAA Fisheries. (2022). Beluga Whale. www.fisheries.noaa.gov.