The humpback whale is impressive in its size. To maintain enough energy for its survival, breeding, and migration, it must eat large amounts of food.
This whale uses several strategies to capture prey.
Humpback whales do not have teeth. They are baleen whales, so instead of biting and chewing, they have filtering plates made of keratin. The whale uses strategies such as lunging, bubble-netting, and seafloor acrobatics to corral small prey. Then it swallows prey-dense waters. The baleen teeth hold the prey in while the water is pushed back out. The whale then swallows the prey whole.
This article will offer more information about the eating and feeding practices of the humpback whale.
In The Mouth: Baleen Plates
Humpback whales are called mysticetes (mustache whales) for their toothless, fringed mouth appearance.
Humpback whales have anywhere from 270 to 400 fringed and overlapping baleen plates suspended from the upper jaw.
These black-colored plates are made of keratin (much like fingernails or hair on people). The plates fray out into fine hair-like strands (like on a comb) on the ends extended down near the whale’s tongue.
Each plate is approximately 30 inches long.
What Humpback Whales Eat
Humpback whales are meat-eating oceanic creatures. However, they do not have sharp teeth to consume their prey.
They primarily eat krill, plankton, and schooling fish such as capelin, sand lance, and herring that are two inches or smaller in size.
Migration For Food
Humpback whales (Megaptera novaeangliae) are mammals that belong to the Balaenopteridae family of baleen cetaceans (marine mammals).
Humpback whales can be found in worldwide oceanic water along coasts, traveling from warmer to cooler waters.
For example, some whales move from Mexican waters for breeding to California or Alaska for feeding. Others will breed near Costa Rica and then migrate to feed off southern British Colombian waters.
A humpback whale eats up to 3,000 pounds (1 1/2 tons) of food daily in its summer feeding grounds. It is speculated that whales only eat during the summer migration to build up blubber (fat).
They can lose 25% to 40% of their body mass as they migrate to winter breeding waters. This is when the whale depends on its fat reserves to sustain itself.
How Humpback Whales Feed
Humpback whales filter feed with their baleen teeth obtaining food by lunge feeding, bubble netting, and other strategies to corral, disorient, or herd prey. These may also be done in conjunction with other whales.
As a whale feeds, the whale opens its mouth, and 14 to 35 pleated grooves in its throat (ventral pleats) expand to about 12 to 15 inches in diameter.
This is relatively small for the size of the whale, meaning it would have great difficulty swallowing larger prey since it does not have teeth to chew.
However, large amounts of water and small food can be taken into the mouth.
As the humpback whale closes its mouth, it uses its tongue to expel the water through the baleen plates. The food stays in its mouth to be swallowed whole and digested.
Strategies To Capture Prey
The following strategies have been observed in humpback whales as they capture prey.
Often lunging is seen in areas with dense and rich food resources.
Humpback whales can lunge and dive in the water, diving at depths of 984 feet, and holding their breath for 12 minutes or more.
As they move, they take in large amounts of water to quickly consume prey in a matter of seconds.
The consumption of this water slows the whale down, so it has to time its movements just right to get the food.
Humpbacks use bubble-netting as a way to feed in coordinated groups of whales.
To do this, they exhale bubbles while swimming in a spiral motion under a dense area of food creating a force that moves inward.
The curtains of bubbles and spiral motion push and trap the prey into the middle of the collection area.
The prey is then pushed towards the surface and the whales lunge to engulf the food.
The humpback feeds on small prey found on the ocean floor, such as sea lances.
Through whale observation, scientists found that they displayed feeding actions by performing repetitive scooping, side-rolls, and side-roll inversions.
Most commonly observed is a 90-degree side roll with the whale’s head pointed down about 30 degrees.
These motions stir the waters and ocean floor, bringing the fish up in large quantities. This allows the whale to take a big gulp of a larger amount of food.
Whales have been found to have scars from their seafloor acrobatics as a result of engagement with fishing equipment on the seafloor and other abrasive objects they roll over.
They can also be seen side-rolling a part of their lunging behavior near the surface of the water in prey-dense areas.
This video shows a humpback whale side-rolling near the surface for feeding:
Humpback whales are baleen whales, meaning that instead of teeth they have keratin plates.
These plates hang from the upper jaw, filtering prey out of large volumes of swallowed water, while swallowing the prey whole.
Humpback whales will use acrobatics to stir up prey from the ocean floor or will lunge through prey-dense waters to capture food.
They also will work in groups with other whales to use a bubble-netting strategy. This is when the whales release bubbles and swim in a spiral motion to push prey into a denser formation for consumption.
Humpback whales can only expand their throats about 12 to 15 inches wide, so they cannot swallow large prey.
They must obtain high volumes of small prey such as krill and small fish to maintain their size for survival, breeding, and migration.