Prehistoric beaver teeth unearthed

Fossilized teeth found amid orange-tinted volcanic ash show that Central Oregon was beaver country long before there was a state, scientists say.

The pair of molars are from a beaver that lived 7 million to 7.3 million years ago — making it the oldest record of the animal in North America — said Josh Samuels, chief of paleontology at the John Day Fossil Beds National Monument.

“It’s essentially the same as a beaver today,” he said.

The teeth will be put on display at the monument’s Thomas Condon Paleontology Center.

Asian immigrant

The world’s oldest remnant of the bucktoothed, flat-tailed rodent as it’s known today is 10 million to 12 million years old and was found in Germany, Samuels said. Scientists speculate that the beaver crawled its way through Asia and then to North America via the Bering Land Bridge, which was exposed by low sea levels between Siberia and Alaska.

The latest teeth, found last year just outside the monument, give a clue of when that long walk may have ended.

In dating fossils, scientists test the age of elements in soils found around the fossil rather than the fossil itself. Those tests revealed the 7-million-to-7.3-million-years -ago age range.

Before the latest discovery, made official by an article in the current issue of the Journal of Paleontology, the oldest remains of modern beavers in North America were 5 million years old and were found in Northern Oregon, Nebraska and California.

The recently discovered teeth were unearthed from land overseen by the Bureau of Land Management adjacent to the monument about 115 miles northeast of Bend. After first seeing the teeth in fall 2009, John Zancanella, paleontology program coordinator for the BLM in Oregon and Washington, returned this spring to collect them. “I knew I had a rodent, but I didn’t know it was a beaver,” he said.

Along with its prominent place on the back of the state’s flag, the beaver is also the mascot for Oregon State University, so it’s fitting that Oregon can lay claim to having the oldest beaver in North America, said Steve Foss, regional paleontologist for the BLM in Salt Lake City.

Having worked at the monument earlier in his career, Foss was keen to the state’s scholastic rivalry between OSU and the University of Oregon’s Ducks. He said the sediment around where the teeth were found was orange, like one of OSU’s team colors.

While there is also green sediment around the fossil beds, there haven’t been any duck discoveries. “They have been looking for 100 years and they still haven’t found a duck out there,” Foss said.

The oldest ducks worldwide date back to about 30 million years ago in France, Samuels said. In North America, the oldest ducks date back to 25 million years ago in Nebraska. In Oregon, they date back 5 million years.