In a groundbreaking revelation, researchers from the Museums Victoria Research Institute have reshaped our understanding of whale evolution, challenging previously held beliefs about the emergence of giant baleen whales. The open-access paper, “Giant baleen whales emerged from a cold southern cradle,” co-authored by paleontologists Dr. James Rule and Dr. Erich Fitzgerald, presents a paradigm shift in our perception of the largest creatures on Earth.
For years, it was widely accepted that the onset of the Ice Age in the Northern Hemisphere approximately 3 million years ago triggered the evolution of massive baleen whales. However, the new research overturns this theory, suggesting that this evolutionary leap occurred much earlier—around 20 million years ago—in the Southern Hemisphere.
The pivotal discovery stems from an overlooked fossil in the Museums Victoria collection: the front end of the lower jaw of a colossal whale dating back to 21–16 million years ago. Initially recovered from a South Australian cliff face in 1921, the fossil gained significance a decade ago when Dr. Fitzgerald recognized it as the largest baleen whale known to be alive during that period.
In their paper, Dr. Rule and Dr. Fitzgerald, along with a team from Australia and New Zealand, demonstrate that whales attained colossal sizes first in the Southern Hemisphere, contradicting the previous belief that the Northern Hemisphere played a primary role in their evolution. The Murray River whale fossil, found in the Southern Hemisphere, disrupts the conventional understanding based on Northern Hemisphere fossils.
Dr. Fitzgerald emphasizes the importance of the Southern Hemisphere, particularly Australia, as a frontier for fossil whale discovery. The Murray River whale and similar finds challenge and refine the global perspective on ancient oceans.
The research also highlights the scalability of the baleen whale jaw tip with body size. The estimated length of the Murray River whale, at around 9 meters, suggests that baleen whales were well on their way to evolving into the ocean giants we recognize today, even 19 million years ago.
Factors such as the Antarctic freeze, changes in ocean currents, and the explosion of plankton biomass were identified as key drivers of colossal whale evolution in the South, long before comparable sizes were reached in the Northern Hemisphere.
The Museums Victoria Research Institute, home to Australia’s largest collection of whale fossil specimens, continues to lead in whale evolution research. Ongoing projects, including “Raising Leviathan,” involve collaboration with citizen scientists to extract and study fossils, contributing to a more comprehensive understanding of whale evolution.
Lynley Crosswell, CEO of Museums Victoria, expresses the significance of the revelation, stating that the institute’s commitment to world-leading research is reaffirmed by this discovery. The Melbourne Museum, housing the comprehensive story of whale evolution, invites visitors to explore this fascinating journey as part of its general entry.
