Mammoth prints found by UO group suggest a family trek

UO professor Greg Retallack measures a mammoth footprint

An old path marked by numerous fossilized tracks in south central Oregon’s Lake County may reveal clues about the family dynamics of ancient Columbian mammoths.

The trail, an Ice Age trackway, was discovered by the UO’s Greg Retallack, a paleontologist with the Museum of Natural and Cultural History, while on an exploratory field trip in 2014 with six UO students in a class about fossil plants.

Unsure of exactly what the site might hold, Retallack, along with UO science librarian Dean Walton, returned to the location last year with researchers from the museum, the Bureau of Land Management and University of Louisiana to excavate the trackway.

The team identified 117 impressions, dated to about 43,000 years ago, that are thought to represent footprints of adult, juvenile and infant mammoths in a layer of volcanic soil at Fossil Lake, an ancient basin first excavated by UO science professor Thomas Condon in 1876. The remote site, 65 miles southeast of Bend, is administered by the Bureau of Land Management.

Elephants once roamed much of North America, with woolly mammoths across Alaska and Canada, and Columbian mammoths from Washington state to South Dakota and south into Mexico. Most went extinct about 11,500 years ago, but some isolated populations of woolly mammoth persisted until 4,000 years ago.

Initially, the UO-led team, which included Adrian Broz, now a doctoral student of Retallack’s who had been in the fossil class, quickly zeroed in on a 20-footprint track exhibiting some intriguing features.

“These prints were especially close together, and those on the right were more deeply impressed than those on the left — as if an adult mammoth had been limping,” said Retallack, who also is a professor in the Department of Earth Sciences.

The limping animal wasn’t alone, the six-member research team reported in a study published online ahead of print in the journal Palaeogeography, Palaeoclimatology, Palaeoecology. Two sets of smaller footprints appeared to be approaching and retreating from the limper’s trackway.

“These juveniles may have been interacting with a limping adult female, returning to her repeatedly throughout the journey, possibly out of concern for her slow progress,” said Retallack, the study’s lead author. “Such behavior has been observed with wounded adults in modern, matriarchal herds of African elephants.”

Trace fossils such as those found in trackways can provide unique insights into natural history, Retallack said.

“Tracks sometimes tell more about ancient creatures than their bones, particularly when it comes to their behavior,” he said. “It’s amazing to see this kind of interaction preserved in the fossil record.”

The excavation was done under a Bureau of Land Management permit and funded by a Sandal Society grant from the Museum of Natural and Cultural History, made possible by tax-deductible gifts of at least $1,000 that are used to support field research and educational programming.

Specimens found in Condon’s excavation — along with the rest of Condon’s large collection of fossils — were donated to UO in the early 1900s and form the core of the Museum of Natural and Cultural History’s Condon Fossil Collection. That collection, today, is under Retallack’s direction and boasts upwards of 50,000 fossil specimens.

Last month a new state law went into effect, making the museum Oregon’s default repository for fossils found on state lands. The museum also is a designated repository for artifacts and paleontological specimens collected from public lands administered by the Bureau of Land Management in Oregon, ensuring they are available to future generations for education and research.

—By Kristin Strommer, Museum of Natural and Cultural History