Friday, November 30, 2012

Blue whales perform underwater acrobatics in order to hunt krill more effectively, new research has found.

Baleen whales (a group that includes the blue whale) are lunge-feeders, meaning they catch their prey by moving forward with open jaws and taking in both water and food. Blue whales can take in 100 tonnes of krill and water in as little as 10 seconds. This ability is key to their survival, a
s not only can prey groups be patchily distributed in both space and time but krill also have great escape responses. When you don't know where or when your next meal will come, it becomes extremely important to get as much as you can out of this one.

To develop a better understanding of their feeding strategies, Dr. Jeremy Goldbogen (Cascadia Research Collective) and his team tracked blue whales with multi-sensor tags. Their results showed that when whales were feeding, they sometimes performed 360° rolls. As a whale approaches a group of krill, it rolls 180° and continues to turn as it engulfs the krill and water, having turned a full 360° when prey has been consumed and ready for the next patch.

Similar rolling behaviour has been seen in other rorqual (the largest group of baleen whales) species such as the humpback, but these creatures only execute 150° rolls. In these whales rolling ability was attributed to their long fins and tail flukes. However, given that the blue whale has shorter flukes, it must be putting in greater effort to pull off these acrobatics. "We did not expect to see these types of manoeuvres in blue whales and it was truly extraordinary to discover," commented Dr Goldbogen.

The researchers suggest two reasons for the rolls: orienting body and jaws to feed more effectively (perhaps by anticipating the krill's escape strategy) and helping the whales optimise their view. Since their eyes are positioned laterally, rolling could grant them a greater field of view. Given that searching whales were also observed using these turns, it's extremely likely rolling allows them to better assess the surrounding area.

Photo credit: photolibrary.com (2009).

To read the paper, click here: http://bit.ly/TvtoZK

http://www.bbc.co.uk/nature/20509831

http://phys.org/news/2012-11-blue-whales-precise-acrobatics-video.html

http://www.livescience.com/25077-whales-turn-while-diving.html
Blue whales perform underwater acrobatics in order to hunt krill more effectively, new research has found.

Baleen whales (a group that includes the blue whale) are lunge-feeders, meaning they catch their prey by moving forward with open jaws and taking in both water and food. Blue whales can take in 100 tonnes of krill and water in as little as 10 seconds. This ability is key to their survival, as not only can prey groups be patchily distributed in both space and time but krill also have great escape responses. When you don't know where or when your next meal will come, it becomes extremely important to get as much as you can out of this one.

To develop a better understanding of their feeding strategies, Dr. Jeremy Goldbogen (Cascadia Research Collective) and his team tracked blue whales with multi-sensor tags. Their results showed that when whales were feeding, they sometimes performed 360° rolls. As a whale approaches a group of krill, it rolls 180° and continues to turn as it engulfs the krill and water, having turned a full 360° when prey has been consumed and ready for the next patch.

Similar rolling behaviour has been seen in other rorqual (the largest group of baleen whales) species such as the humpback, but these creatures only execute 150° rolls. In these whales rolling ability was attributed to their long fins and tail flukes. However, given that the blue whale has shorter flukes, it must be putting in greater effort to pull off these acrobatics. "We did not expect to see these types of manoeuvres in blue whales and it was truly extraordinary to discover," commented Dr Goldbogen.

The researchers suggest two reasons for the rolls: orienting body and jaws to feed more effectively (perhaps by anticipating the krill's escape strategy) and helping the whales optimise their view. Since their eyes are positioned laterally, rolling could grant them a greater field of view. Given that searching whales were also observed using these turns, it's extremely likely rolling allows them to better assess the surrounding area. 

Photo credit: photolibrary.com (2009).

To read the paper, click here: http://bit.ly/TvtoZK

http://www.bbc.co.uk/nature/20509831

http://phys.org/news/2012-11-blue-whales-precise-acrobatics-video.html

http://www.livescience.com/25077-whales-turn-while-diving.html

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