A group of researchers have recently determined how humpback whales capture and consume their prey, based on the way they swim.
By attaching tags to five humpbacks and recording high resolution data of the depth, acceleration, and magnetic orientation of 479 dives, they were able to learn more about the whales’ lunging tactics.
They attached tags behind the dorsal fin of three of the humpbacks to record stroke patterns. The tracking device was attached closer to the head on the other two whales in order to measure head movements.
By analyzing acceleration patterns, Malene Simon from the Greenland Institute of Natural Resources noticed that as the whales initiate a dive, they first accelerated upward, then slowed down, and continued to glide. Based on the speed of each state, the team concluded that “the mouth must already be open and the buccal (mouth) pouch inflated enough to create a higher drag when high stroking rates…occur within in lunges.”
The whales continue to accelerate once their mouth is open in order to stretch the pouch as much as possible. Once the pouch is fully inflated, they slow down and swallow their prey–krill and capelin–over a 46 second period. This pattern continues, in a series of lunges, until they are done feeding.
To learn more:
- Read the full press release: Choreography of submerged whale lunges revealed
- Find the results, published in the Journal of Experimental Biology: Keeping momentum with a mouthful of water: behavior and kinematics of humpback whale lunge feeding
Copyright © 2012 by Marine Science Today, a publication of Marine Science Today LLC.