Meet the whales with nerves like bungee cords

Nerves are not known for being stretchy but researchers have discovered that nerves in the mouths and tongues of rorqual whales can more than double their length with no trouble at all.

Those stretchy nerves support the animals' unique and extreme lunge feeding strategy, which helps to support the whales' gigantic bodies.

"These large nerves actually stretch and recoil like bungee cords," said A. Wayne Vogl from University of British Columbia in Canada.

"This is unlike other nerves in vertebrates, where the nerve is of a more fixed length that has enough slack in it to accommodate changes in position of the structures the nerves are supplying," Vogl said.

Rorqual whales represent the largest group among baleen whales, weighing in at an impressive 40 to 80 tonnes.

To eat, the whales open their mouths and lunge while their tongues invert and their mouths fill like giant water balloons full of floating prey. Those prey are concentrated by slowly expelling the water through baleen plates. The volume of water brought in with a single gulp can exceed the volume of the whale itself.

"Rorqual whales attained large body size with the evolution of a bulk filter feeding mechanism based on engulfing huge volumes of prey-laden water," Vogl said.

"This required major changes in anatomy of the tongue and ventral blubber to allow large deformation, and now we recognise that this also required major modifications in the structure of nerves in these tissues so they could withstand the tissue deformation," Vogl added.

The findings appeared in the journal Current Biology.