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U.S. DEPARTMENT OF THE INTERIOR

BUREAU OF LAND MANAGEMENT

Oregon / Washington

Beaver Fossils

North America's Earliest Beaver Discovered in Oregon

Archaeological site

A new fossil find represents the earliest record of living beavers (Castor) in North America. A pair of teeth was found on Bureau of Land Management land near Dayville, Oregon. These teeth come from the Rattlesnake Formation and are between 7 and 7.3 million years old.

The specimens will be going on display in the Thomas Condon Paleontology Center, at John Day Fossil Beds National Monument. The new find is described in an article appearing in the current issue of the Journal of Paleontology. This study was done through a partnership between the National Park Service and the Bureau of Land Management. These agencies work together in Oregon to manage and preserve fossils on public lands, and to promote scientific research that improves our understanding of the past.

Beavers are very important animals today; their tree cutting and dam building activities impact their habitat more than any other animal, besides humans. They are well studied, but the origin and evolution of beavers is still unclear.

Worldwide, the earliest "true" beaver, as we would think of them today, comes from Germany, about 10 to 12 million years ago. These beavers then spread across Asia, and eventually crossed the Bering Land Bridge to North America.

The new find helps resolve when beavers dispersed to North America from Asia, and when the two living species, the North American Castor canadensis and Eurasian Castor fiber, diverged.

Previously, the earliest known records of living beavers in North America were from Nebraska, California, and northern Oregon, and date around 5 million years old. It is fitting that the earliest modern beavers are found in Oregon, since Oregon is the Beaver State, the beaver is the Oregon state animal, and the mascot of Oregon State University.

The fossil teeth found near Dayville are almost identical to living beaver teeth, showing that the animal has changed very little in the last 7 million years. This indicates that their appearance and role in the environment would have been the same in the past.

Beaver teeth

Finds like this help paleontologists to reconstruct past environments. Seven million years ago eastern Oregon is thought to have been mostly a sagebrush/bunchgrass steppe environment, much like today. However, some of the animals were very different at that time; there were mastodons, rhinos, camels, saber-tooth cats, and giant ground sloths. But other animals like the beaver, along with foxes, ground squirrels, and pronghorn, would be very familiar to people living in the area today.

Paleontologists have been studying John Day Basin for well over 100 years, but there is still much more to learn about Oregon's past. John Day Fossil Beds National Monument includes many of the best studied sites, but the vast majority of fossil localities, including the one with these beaver fossils, are found on adjacent Bureau of Land Management administered lands.

The National Park Service and the Bureau of Land Management have co-managed fossil resources in eastern Oregon under an agreement for 25 years, which has resulted in the John Day basin being regarded as one of the most important outdoor laboratories for understanding biological evolution and climate change over the past 40 million years.

Such collaboration between federal agencies has allowed each to fulfill its mission of preserving important resources for future generations while facilitating important scientific research. New finds like this occur regularly, highlighting the importance of preserving fossils on public lands, which aids scientific research and allows the public to enjoy these valuable natural resources.