Extreme nerves for extreme feeding

Professor Wayne Vogl and colleagues at the University of British Columbia discovered that rorqual whales can gulp volumes of water that are bigger than their body. Nerves in the mouth and tongue make this amazing feat possible as they can actually stretch to twice their resting length without sustaining damage. Dr. Vogl was quote in CBC News saying, "The nerves that supply these remarkably expandable tissues in the floor of the mouth of rorqual whales ... are very stretchy, they're like bungee cords." This is unusual as the nerves of most vertebrate species have fixed lengths.

Whale graphic Depiction of a rorqual whale expanding its mouth while feeding. Image from Univ British Columbia.

Rorqual whales are a type of baleen whale (Balaenopteridae) that feed by scooping up large volumes of water and food as shown above. They are among the largest mammals that have existed. Amazingly, the volume of water taken up can be greater than the whale itself.  Dr. Vogl's team discovered the stretchy nerve by accident while studying oral muscles. Interestingly, the nerve fibers are not all that stretchy. Rather, the nerve fibers fold and unfold inside a protective sheath (below).

nerve stretch Tongue nerve with and without stretching. Image from UBC.


CBC News, British Columbia

Vogl AW, Lillie MA, Piscitelli MA, Goldbogen JA, Pyenson ND, Shadwick RE. Stretchy nerves are an essential component of the extreme feeding mechanism of rorqual whales. Current Biology. 25(9): R360–R361, 2015. DOI: http://dx.doi.org/10.1016/j.cub.2015.03.007

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