Clam Survey Dredges Up Ice Age Find

Scientists participating in our 2024 Surfclam and Ocean Quahog Survey aboard the F/V ESS Pursuit made an amazing once-in-a-lifetime discovery! It happened during their second dredge haul. As usual, scientists brought the dredge sample aboard the vessel, deposited it onto a series of whirling conveyor belts, and delivered it to the processing area for data collection. While the sample had barely any clams in it, the team noticed it had one quite odd-looking… thing.

They could tell it was a bone of some sort-probably a jawbone by the looks of it. But, from what? It was kind of big. Too big to be a seal jaw, but too small and the wrong shape to be a whale. And it had teeth.

"I honestly had no idea as to what this was. The tooth count, the size of the teeth, and just the overall density of the bone made me feel that this was something that needed a further investigation," said Jonathan Duquette , chief scientist for the survey. "I kept looking online for Virginia fossils-to see if we could draw some correlation. The desire to identify this thing is what compelled us to keep it. So, I placed it at the watch chief station and would stare at it, almost daily. I knew we had to figure this mystery out."

The survey continued and during breaks and downtime, Duquette searched online for anything that might help identify what this jawbone could be from. He wasn't having much luck with his online search. So there it sat, nagging at him. On a whim and determined to solve the mystery, he reached out to Dr. Nick Pyenson . Pyenson is the lead curator and head of the Smithsonian's National Museum of Natural History's Department of Paleobiology , and a specialist in fossil marine mammals.

"As soon as I saw the photo attached to Jonathan's email, I knew it was a walrus jaw. They have a thick and chunky look to them. Jonathan's email also said 'very dense,' which is another telltale clue, along with its context," said Pyenson. "At the Smithsonian, we have the world's best collection of Atlantic Ice Age walrus bones. Most of our collection was collected under similar circumstances-from dredges or trawls."

About 90 minutes after Duquette sent his email, he heard back from Pyenson. Fortunately it was only Duquette's jaw that hit the floor when reading the response. Pyenson identified the bone as the right jawbone of a likely extinct walrus.

Today's walruses largely live in several populations on coasts and island archipelagos around the Arctic Circle. Sometimes, individuals will find themselves far south, but that's rare. During the Ice Ages, hundreds of thousands of years ago, walruses had a much broader geographic range. Scientists base this knowledge on walrus bones found as far south as South Carolina and Florida. These Pleistocene fossils and sub-fossils-bones that haven't quite turned to rock-have been found on the seafloor and occasionally on beaches along the U.S. East Coast.

Pyenson said in some cases he and his team can determine the age of bones from radiocarbon dating . And because this jawbone has teeth, sometimes they can extract ancient DNA. Cue the Jurassic Park theme.

"Radiocarbon dating works well with bones of this age. Recent advancements in DNA sequencing technologies have opened the window to collecting ancient DNA from specimens. If we're fortunate, we can begin the work of placing this survey specimen into the genealogy of walruses, and how walruses have changed over time," Nick said.

Pyenson asked if we'd be interested in donating this specimen to their collection. Our answer-a resounding YES!!!

"This whole experience has been awesome and a great opportunity for collaboration between NOAA Fisheries and the Smithsonian," Duquette said. "To be able to put eyes and hands on something that hasn't been seen in potentially thousands of years and share it with others is pretty amazing!"