Over the weekend of October 18, paleontologists with the Idaho Museum of Natural History (IMNH) recovered remains from a 72,000-year-old mammoth. One tusk and partial skull were found near the American Falls Reservoir.
Water levels drop temporarily in the reservoir each year, giving a chance for students at Idaho State University and paleontologists to spot fossils that have been uncovered due to erosion. A volunteer happened to spot bones about 9 meters (30 feet) below the high water mark in a location used for irrigation drainage. This location left only a small window for the team to retrieve the mammoth’s bones, as the water was starting to rise quickly.
“We’re very lucky to have recovered them,” U.S. Bureau of Reclamation field office manager Roland Springer said in a press release. “Had they not been reported to Reclamation, the fossils may have been eroded and carried away into the reservoir.”
Fossil discoveries on federal land cannot be excavated without approval from the U.S. Bureau of Reclamation. Federal law requires those who discover fossils to take pictures and record coordinates of the site, which are then submitted for approval. The precise location is not released in order to prevent unscrupulous people from stealing the bones with unauthorized digs. Not only would such a dig rob researchers of the opportunity to study the fossils, but improperly-executed excavations could damage the reservoir and other potential sites as well.
Because rising waters were threatening the dig site, the Bureau of Reclamation swiftly gave the IMNH team permission to retrieve the bones.
Over two and a half days, the majority of the right tusk and part of the skull were removed. Rings in the the tusk, which is 19 centimeters (7.5 inches) in diameter, allowed the scientists to determine that the animal was likely 16 years old at the time of its death. Though 16 is fully grown for a mammoth, it was much shorter than the 60-80 years predicted to be the average life expectancy.
The fossils were protected by plaster casts during the recovery and have since been transferred to the Idaho Museum of Natural History at ISU. Closer analysis must be done before their fate is ultimately decided.
“The exposed fossil will be cleaned and prepped for long-term storage or possibly exhibit, depending on its state of preservation,” commented Mary Thompson of IMNH, who led the excavation team. “This find is exciting because there are still teeth in place in the jaw – so much can be learned from that.”
Because the fossils were removed with such urgency, the team didn’t have a lot of time to explore the surrounding area for additional bones. Once the skull and tusk were removed, soil and protective geotextile fabric were added to slow the force of erosion. Thompson plans to return to the site next year with more equipment in hopes of finding more of the skeleton.
Of course, a critical component of that future dig will be the group of volunteer ISU students.
“We couldn’t have completed the project without the students that were involved,” Thompson added. “They did the most work on this project. This is exactly the kind of experience that can’t be taught in a classroom. Our students get unique opportunities like this to work in the field.”
[Hat tip: LiveScience]