Humpback whales feed on invertebrates and fish. Every summer, they use to swim in cold seas and they suddenly jump out of the water, mouths agape, in scenes like this:
During a feeding unge, the whale's throat expands tremendously. This expansion is aided by throat pleats, or folds, which open up, accordionlike, to as far back as the navel. The whale closes its mouth around tons of water and prey and then pushes the water out through about 300 baleen plates that hang from the upper jaw and act as a sieve.
The Humpback has the most diverse repertoire of feeding methods of all baleen whales. Its most inventive technique is known as bubble net fishing: a group of whales blows bubbles while swimming to create a visual barrier against fish, while one or more whales in the group make vocalizations that drive the fish against the wall. The bubble wall is then closed, encircling the fish, which are confined in an ever-tighter area. It is one of the more spectacular acts of collaboration among marine mammals.
As the whales approach the surface, they open their mouths wide and aspirate from their blowholes. As humpbacks open their mouths, their jaws are able to "unhinge" and extend to create a larger area for consuming prey. The frightened prey turn, once again toward the surface of the water and are in perfect position to be consumed by a big gulp of water and prey as the whales break through the surface of the water in an awsome spectacle of whales exploding out of the water.
Evidence suggests that there is one whale that blows the bubbles that manipulate the prey. The responsibility of that whale is to produce a curtain of ascending bubbles that create a wall through which the school of fish will not pass.
Finally, a couple of videos you must see:
More info and sources: 1, 2, 3 / See also: Orcas Teamwork
30 octubre 2007
Imagine a 4-metre-wide mouth coming out of the water. With its 40-ton enormous body, the Humpback Whale is able to swallow a ton of water and thousands of fish in just one gulp.