Baleen Whale Lunge Report Unravels Evolutionary Highway

Image Doug Perrine Barcroft Media

For the second week in a row the evolution of Baleen Whales is breaking ground and breaking international news. Just days after experts from New Zealand revealed a complete Tree of Life for Baleen Whales for the past 40 million years researchers of the University of British Columbia UBC have discovered just how Baleen Whales take on lunge feeding. 

The News Department of the University of British Columbia Canada communicated that finally the mystery on how whales can double their mouth and tongue length was broken. “A unique nerve structure in the mouth and tongue of rorqual whales that can double in length and then recoil like a bungee cord,” was the revelation of the study. 

Baleen Whales evolution traces back from ancestral earth dwelling creatures to marine jawed  whale type organisms -made evident in 2011 by the discovery of the Fossil Janjucetus hunderi. Ancient Baleen Whales hunted for single prey and later evolve to Baleen for filter lunge feeding. The evolution of Baleen Whales and their success as an ecological group was made possible due to specific anatomical adaptations. 

The most important adaptations of Baleen Whales were the enlargement of the skull, the replacement of toothed jaws with baleen combs and the anatomical empowerment to expand their mouth to lunge feed on microorganisms. This energetic prey strategy allowed them to obtain more energy from the environment by lunge feeding instead of wasting energy in large prey hunt down. Baleen whales took on these evolutionary mutations in times when the Antarctic Current was rising allowing nutrients to flow richly, a time grandly influenced by global climate change events.

Questions on when did the nerve came to be, fossil evidences, why it appeared and what kind of evolutionary jump -a fast mutation or a gentle step formation led to nerve formation remain unanswered and matter of study. 

The stretchy nerves explains how the massive whales are able to balloon an immense pocket between their body wall and overlying blubber to capture prey during feeding dives.

“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.

Pyenson Lab reported on May 9th on the words of Wayne Vogl, professor in the Department of Cellular and Physiological Sciences at UBC who in the past years working with a group of researchers took several studies to understand baleen whales. From biomechanics, functional and evolutionary morphology of large baleen whales, fluid dynamics and parachute physics and anatomy the group spared no efforts in understanding Baleen Whales. 

Even after publishing at Current Biology the pàper which describes the unusual morphology of throat pouch nerves in rorqual whales the group concluded that questions on how baleen whales lunge feed remain unanswered. 

The group highlights the expansion of the mouth which takes place in less than 10 seconds, “requiring a complete reconfiguration of their basic mammalian jaw and throat anatomy”.

Lead researcher, Erich Fitzgerald from the Museum Victoria in Melbourne, explains that baleen formation was not the only necessary anatomical modification which Baleen Whales had to take on to become successful in their final adaptation. 

"The Fossil Janjucetus hunderi is compelling evidence that these archaic baleen whales could not expand and rotate their lower jaws, which enables living baleen whales to engulf and expel huge volumes of seawater when filter feeding on krill and other tiny animals," the expert fills in the blank pages of the evolution tree of Baleen Whales. 

Baleen Whale evolution even traces further back in time. On April 16th Pyenson Lab reported that a new paper links Whales, sea cows, sea otters, penguins, and sea turtles — all iconic marine species to a “deep-evolutionary connection”, they are all Tetrapods.

The marine animals belong to separated branches of evolutionary highway which took land mammals to ocean environments as the millennia past on. 

What do these many returns to the sea tell us about how major ecological transitions happen over geologic time? And what do they tell us about the ecological future? Wider questions echo.

International press which picked up the report on the discovery of nerves by the University of British Columbia UBC reported that the researchers ignore if other animals are capable of doing what Baleen Whales do. 

“This discovery underscores how little we know about even the basic anatomy of the largest animals alive in the oceans today,” Nick Pyenson UBC postdoctoral fellow currently curator of fossil marine mammals at the Smithsonian’s National Museum of Natural History stated. 

“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.”