Gigantic whales have super cool 'bungee cord' nerves
The new discovery sheds light on how baleen whales can undertake such massive feedings.
When presented with the hypothetical choice of superhero powers, I’ve always leaned toward super-stretchy limbs. How practical it would be to have the ability to extend a leg through the house to close a door or to snake an arm across the street to nab a villain.
As it turns out, rorqual whales aren’t too far off. Researchers from the University of British Columbia (UBC) made the remarkable discovery that these marine mammals possess a unique nerve structure in the mouth and tongue that can double in length and then snap back like a bungee cord. Rorquals are the largest group among baleen whales, and include blue whales and fin whales.
The elastic nerves solve the mystery of how these big guys are able to create such an immense pocket between their body wall and overlying blubber to capture prey while feeding.
© Universtiy of British Columbia"This discovery was totally unexpected and unlike other nerve structures we've seen in vertebrates, which are of a more fixed length," says Wayne Vogl of UBC's Cellular and Physiological Sciences department.
"The rorquals' bulk feeding mechanism required major changes in anatomy of the tongue and mouth blubber to allow large deformation, and now we recognize that it also required major modifications in the nerves in these tissues so they could also withstand the deformation," he added.
The nerves of us non-superhero humans are unable to stretch without damage, but in these whales, the nerve cells are arranged inside a central core in a way that the individual nerve fibers can fold and unfold.
"Our next step is to get a better understanding of how the nerve core is folded to allow its rapid unpacking and re-packing during the feeding process," says UBC zoologist Robert Shadwick.
It is possible, but unknown, if similar mechanics are at play in other animals as well, like the ballooning throats of frogs or the lightning-fast tongues of chameleons.
"This discovery underscores how little we know about even the basic anatomy of the largest animals alive in the oceans today," says Nick Pyenson, from the Smithsonian's National Museum of Natural History. "Our findings add to the growing list of evolutionary solutions that whales evolved in response to new challenges faced in marine environments over millions of years."