Marine biologists expect to find all sorts of strange stuff in the deep sea, but a mammoth tusk ain’t one of them.
Marine biologist Steven Haddock and ROV pilot Randy Prickett first spotted the tusk in 2019 while aboard the R/V Western Flyer, and it appeared as though they’d stumbled upon an elephant tusk. The duo, as members of a Monterey Bay Aquarium Research Institute (MBARI) expedition, were investigating a deep sea mount located some 300 kilometres off the California coast.
Haddock and Prickett returned to the scene in July 2021, as they had only been able to retrieve a small portion of the tusk during their initial visit. Using ROV Doc Ricketts and working at a depth of over 3,070 metres, they managed to collect the entire 1-metre long tusk, according to an MBARI press release. Back on shore, the team was able to confirm the tusk as belonging to an extinct Columbian mammoth (Mammuthus columbi).
“In the deep sea, we find lots of amazing animals which people would not believe exist on Earth, but finding this mammoth tusk, so deep and so far from shore, was by far the most improbable thing I’ve experienced,” Haddock wrote to me in an email.
Randy Prickett (left) pilots an MBARI ROV, while scientist Steven Haddock (right) documents the mammoth tusk before the retrieval operation. (Photo: Darrin Schultz © 2021 MBARI)
“As it dawned on us that this was actually a mammoth, my head began to spin imagining how it came to rest atop this remote seamount,” he added. “It is still hard for me to believe how it sat there for millennia without being destroyed or buried before we stumbled across it.”
The exquisite preservation of the as-yet-undated mammoth tusk was made possible by the cold, high-pressure environment of the deep ocean, which is “different from almost anything we have seen elsewhere,” Daniel Fisher, a University of Michigan paleontologist and a member of the investigating team, explained in the press release. “Other mammoths have been retrieved from the ocean, but generally not from depths of more than a few tens of meters.”
Haddock (left), UC Santa Cruz postdoctoral researcher Katie Moon (centre), and University of Michigan paleontologist Daniel Fisher (right) inspecting the oversized tusk in the ship’s lab. (Photo: Darrin Schultz © 2021 MBARI)
It’s hard to know exactly how the mammoth tusk ended up so far from shore, but scientists have seen this sort of thing before. Animals carcasses, whether from Cretaceous dinosaurs or modern alligators, will sometimes sink to the sea bottom after getting swept out into the ocean, whether by tides, floods, or tsunamis. It happens.
A team of interdisciplinary scientists, including paleontologists, geneticists, oceanographers, and geochronologists, is now planning to study the tusk from all sorts of different angles. CT scans will provide 3D views, revealing its composition and internal structure. The team will also attempt to extract and sequence the mammoth’s DNA. Together, these techniques could shed light on the animal’s history, age, and lineage. Importantly, they could also reveal new insights into the evolution and spread of mammoths in North America.
Haddock and Fisher, along with oceanographers from UC Santa Cruz, are trying to narrow down the potential sites on land where the mammoth could have originated. Mineral crusts on the tusk could indicate how long it’s been resting on the seafloor, while a retracing of ancient ocean currents could point to its coastal starting point. “We were wondering if it could have drifted all the way from Alaska, or if it took the short route from the California coast. Stay tuned to find our conclusions,” Haddock told me.
Indeed, this is all very preliminary, as the scientists are taking this opportunity to announce the discovery of the specimen and disclose the chosen avenues of research. This mammoth tusk has stories to tell, and we’re very much looking forward to the details.