By Nat Hab Expedition Leader Eddy Savage
Humpback whales are among the most widespread and successful cetaceans inhabiting Earth’s oceans. These baleen whales lack teeth, possessing instead dozens of rows of keratin protein aligned in fibrous plates along the roofs of their mouths. Humpbacks have between 270 and 400 baleen plates. To maintain their 40-ton physique, each whale needs to filter over a thousand pounds of prey through their baleen each day. While in their summer feeding grounds, this amount can reach upwards of two thousand pounds per whale per day!
Baleen whales have evolved to be the largest creatures in the world due to their clever energy-saving feeding tactics: consuming lots of small prey versus a few larger ones. They rely on the ocean’s abundance of small creatures, including krill, copepods, anchovies, herring and sand-lance, among other small schooling fish.
The humpback whale is renowned for being one of the most creative baleen whales when it comes to feeding strategies and utilizes many environmental features to its advantage. Seafloor contours, tidal currents, diving seabirds, opportunistic gulls and the teamwork of other humpback whales are all part of their feeding strategy repertoire. Watching humpback whales feed in the wild is sensational.Humpback whales are a highlight on nature adventures in Alaska and British Columbia. Lucky travelers may witness them feeding—know what to look out for!
Here are five different methods humpback whales use to secure a meal:
1. Deep Dive Feeding
Solitary humpbacks make deep, five-to-ten-minute dives to where their prey is congregated. Krill, for example, make vertical migrations of hundreds of feet through the water column each day, and the humpbacks dive to find them. Typical dives are roughly 200 feet deep and can last between five and seven minutes.
The humpbacks may use a steep rock wall or sea-floor feature to corral their prey into a tighter ball. Once cornered underwater, the whale opens its mouth and closes around the prey. Using its tongue, the whale pushes the excess water out of its mouth and filters the prey through the many plates of fibrous baleen. With only the prey remaining, the whale then swallows its catch. This is an energy-conscious method of hunting, and humpbacks seem relaxed while feeding in this way.
Observing a humpback whale in a large inlet on the coast of British Columbia revealed the contours of the seafloor on the nautical chart. It was evident that the whale was making a large semi-circle around a steep rock ridge and then swimming quickly in from several hundred feet away. It would then emerge within fifty feet of the edge of the steep shoreline and pause for a couple of breaths. This humpback whale appeared to be using the steep rockface below the water to corner and trap its prey.
Trap feeding is a relatively newly observed humpback hunting strategy. Humpbacks in the waters off the south and central coast of British Columbia have been observed spending as little energy as possible to catch their prey.
Initially, the humpback lays vertically in the water and opens its gigantic mouth wide. The roof of its mouth extends high into the air, while the lower jaw lays flush with the surface of the water. The humpback then uses its 15-foot-long pectoral fins to craftily direct prey into its mouth. When it has collected enough prey, it closes its mouth, pushes out the water, and enjoys its meal.
This type of feeding was first documented in the waters off British Columbia, Canada, in 2011, where only two whales were practicing trap feeding. Today, nearly 30 known individuals practice it, suggesting it is a learned and observed skill.
Flick feeding requires the humpback to have its head down and only its tail above water. Stabilizing itself vertically with its giant pectoral fins, the humpback flicks huge quantities of water (and krill) repeatedly in the air, appearing as tail slapping. It is hypothesized that flicking krill through the air temporarily stuns the small crustaceans, making them an easy feast.
Flick feeding bouts usually last five to ten minutes, after which the whale spins around, mouth open, and eats the stunned krill on the surface of the ocean.
Lunge feeding is one of the most fascinating feeding strategies. During lunge feeding, humpbacks use ocean currents, diving seabirds, and gulls flying overhead to their advantage.
The common murre, rhinoceros auklet and Cassin’s auklet hastily dive by the hundreds to catch their “forage fish” prize in British Columbia. Each bird makes multiple trips, attacking the school of fish from every direction, causing the fish to school together into a large, dense, swirling ball—their survival strategy. The diving seabirds then begin pushing the ball of “forage fish” tighter together and toward the surface of the water. The fish start burbling at the surface as they become surrounded and have no escape route.
Enter the gulls: Spotting the commotion on the surface of the water, they fly over from every direction. Once above the burbling fish, the gulls repeatedly swoop down into the boiling ball of fish and take their share.
From a whale-watching vessel, you can see the swirling gulls collecting over a ball of forage fish, and it is usually possible to pinpoint where there will likely be an imminent lunge feed. The humpback whales enter the scene now, potentially following vibrations in the water from the swirling forage fish and plotting their course. Moving quickly toward their prey, they make a deep dive several hundred feet away from the ball of fish. At this moment, all you can hear is the cacophony of frantic gulls crashing into the water.
In an instant, there is complete silence, and the gulls pause their feeding and lift off the surface several feet. They have sensed the incoming humpback. And right on time, 45 tons of whale emerges from beneath the ball of forage fish with its mouth wide open. Rising half its body length out of the water with its mouth open wide, the humpback quickly shuts its mouth, sometimes accidentally catching a slow gull, and pushes the water through the baleen to devour its prey. (The whales let the gulls go; a few confused and soaked gulls have been observed being released by a humpback!)
And just like that, the flurry of swirling gulls disperses, the diving seabirds become quiet and calm, and the humpback whale moves off in search of its next ball of forage fish to devour.
Bubble Net Feeding
Perhaps the most well-known humpback feeding strategy is bubble net feeding. Individual whales can bubble net on their own, but for the most part, they work together in larger groups. Observations of humpback bubble netting range from individuals to groups of more than 15 whales. In a coordinated movement, the whales swim in a wide circle beneath their prey and gently exhale air from their blowholes. The stream of bubbles rises to the surface and creates a visible and audible barrier for small fish and krill. Frightened by the bubbles, the prey will school together and rise to the surface in the center of the ring of bubbles.
The lead humpback whale then makes a loud trumpeting call beneath the water, signaling for the rest of the group to follow. They then swim up through the center of the bubble ring with their mouths wide open, capturing the startled prey in their massive jaws. The trumpeting call continues for several minutes after the bubble net feeding concludes, almost as if the whales are celebrating their success.
Want to help protect humpback whales? Adopt one through our conservation partner, World Wildlife Fund!