Sensory Organ Discovered in Jaws of Rorqual Whales

Blue whale study done by Richard Ellis, in preparation for Jacobs Gallery mural. The distinctive throat pleats of all rorquals are clearly visible in this image. From NBWM collections, 2000.10.

Another exciting discovery has been made by cetacean biologists, this time in one of the four Families of the suborder Mysticeti (baleen whales).  The Balaenopteridae are also called rorquals, a reference to the throat pleats that run from chin to the middle of their bodies.  The term rorqual is based on the Norwegian word royrkval, which means ‘furrowed whale’.

Rorquals are the largest family of baleen whales, consisting of nine species, including the blue and humpback, which are represented in our Jacobs Family Gallery, and the fin and minke, which are commonly seen during whale watch tours in Massachusetts waters.  They all feed by gulping large amounts of water into their expandable throats and then forcing that water through their 500-800 plates of baleen back into the ocean. The animals that are left behind, typically krill or small fish, then get swallowed. This process is also known as lunge feeding. It requires an incredible amount of muscle power, since the whales are working against immense volumes of water. We all know how hard it is to run through water. Imagine trying to swim through it with your mouth open, a mouth that takes up 20% of your body length.

Several articles published on Wednesday, including this one, explain how the newly discovered sensory organ, located between the tips of the mandibles, regulates the feeding process.

The actual scientific paper that reports the discovery was published yesterday in the journal Nature. For those who want a more scientific explanation, the abstract from that paper, authored by the Smithsonian’s Nick Pyenson, and several others, can be viewed here.  Mr. Pyenson was one of the people summoned to the Atacama Region of Chile last year when a highway project unearthed dozens of fossil whale skeletons, and they had to be removed and taken away quickly.

The next time you’re at the New Bedford Whaling Museum, in the Jacobs Family Gallery, take a look at the lower jaws of the blue and humpback whale skeletons. You’ll notice that the lower jaws, unlike toothed whales or humans, are not connected at the tip (symphysis). In between those mandibles would be the organ described in the article. If you look at the North Atlantic Right Whale you’ll notice the same lack of fusing between mandibles. However, since right whales are not rorquals (they don’t have throat pleats) they would not have this sensory organ.

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