From teeth to baleen: Fossils hold clues

How, when and why did baleen whales lose their teeth? Researchers are turning to the Burke’s extensive collection of fossil baleen whales from the Pacific Northwest to better understand how the largest creatures on earth evolved.

Modern baleen whales have a bristle-like material called baleen in their mouths. When the whale takes in mouthfuls of water and forces it out through the baleen, the baleen’s fibers act as a strainer, catching small marine animals (such as krill). But that wasn’t always the case.

In December, a team of researchers at the University of Otago published that a North Pacific fossil whale in the Burke collection was a new species of toothed ‘baleen’ whale. The whale, which they named Fucaia buelli, was one of the oldest baleen whales ever found, having lived 33 to 31 million years ago during a time of significant global climate change. Unlike today’s modern baleen whales, Fucaia had well-developed teeth that were used to hunt and chew its prey.

“As the prey became smaller, teeth became increasingly obsolete and, ultimately, were lost completely in modern baleen whales"

— Ewan Fordyce

In the article “Researchers describe new North Pacific fossil whale,” co-author Dr. Felix Marx explains that Fucaia likely “captured its prey using its teeth and perhaps strong suction” based on wear patterns on the teeth. He continued, “Suction feeding likely enabled early whales to move from a tooth-based feeding style to a filter-feeding, by allowing them to capture smaller prey items than teeth alone could handle.”

In the same article, co-author Dr. Ewan Fordyce notes that the suction behavior “may have prompted the evolution of baleen from the enlarged gums, possibly as a more efficient way to expel the water sucked in with the food. As the prey became smaller, teeth became increasingly obsolete and, ultimately, were lost completely in modern baleen whales.”

This research gives scientists a better understanding of how these whales evolved and is just one of several studies utilizing fossils from the Burke collection. Dr. C.H. Tsai, a postdoctoral research fellow with the National Museum of Nature and Science in Japan and co-author on the Fucaia publication, recently visited the Burke as a recipient of the Burke Museum vertebrate paleontology study grant to continue his research into baleen whale evolution and look at another toothed whale fossil.

“I was lucky to be involved in describing Fucaia buelli,” Tsai said. “Toothed whale fossils are extremely interesting and important because they are the key to helping us understand a major evolutionary breakthrough: how whales went from having teeth to baleen.”

researcher studying skull fossil

Photo: Burke Museum

During his time at the Burke, Tsai studied the partial skeleton of a toothed ‘baleen’ whale (Chonecetinae) that lived 33 to 29 million years ago. The fossil was found in the Twin River Formation along the coast in Clallam County, Washington, in 1992.

fossil of a jawbone

Photo: Burke Museum

“I am hoping to describe one more toothed ‘baleen’ whale curated at the Burke to improve our understanding of baleen whale evolution,” he said. This will be “a step forward to decipher the origin of the largest animals on earth.”

The Burke collections are referenced constantly for answers to a wide range of questions about our natural world. With each research inquiry and new discovery, our understanding of the past shifts and grows along with our ability to inform future decisions.

We look forward to seeing what new discoveries are uncovered!


For more information: Marx FG, Tsai C-H, Fordyce RE. 2015 A new Early Oligocene toothed ‘baleen’ whale (Mysticeti: Aetiocetidae) from western North America: one of the oldest and the smallest. Royal Society Open Science 2: 150476.

Learn more about the Burke Museum’s Vertebrate Paleontology Collection or the Vertebrate Paleontology Collection study grant.

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