An Ice Age Discovery Just Outside Grangeville
Only a few miles west of Grangeville, beneath the quiet waters and sediments of Tolo Lake, lies evidence of a much different Idaho.
Thousands of years ago, Columbian mammoths, ancient bison and other animals traveled across what is now the Camas Prairie. In 1994, a project intended to improve wildlife habitat at Tolo Lake unexpectedly uncovered their remains and revealed one of the most remarkable prehistoric discoveries in Idaho.
What began with the discovery of a single enormous bone would lead to a major scientific excavation, hundreds of recovered fossils and a summer that captivated the Grangeville community. Today, visitors can see an actual mammoth humerus excavated from Tolo Lake on display at the Grangeville Visitor Center.
Only a few miles west of Grangeville, beneath the quiet waters and sediments of Tolo Lake, lies evidence of a much different Idaho.
Thousands of years ago, Columbian mammoths, ancient bison and other animals traveled across what is now the Camas Prairie. In 1994, a project intended to improve wildlife habitat at Tolo Lake unexpectedly uncovered their remains and revealed one of the most remarkable prehistoric discoveries in Idaho.
What began with the discovery of a single enormous bone would lead to a major scientific excavation, hundreds of recovered fossils and a summer that captivated the Grangeville community. Today, visitors can see an actual mammoth humerus excavated from Tolo Lake on display at the Grangeville Visitor Center.
An Unexpected Discovery
In 1994, Tolo Lake had been drained as part of a project to deepen and rehabilitate the lake for fish and wildlife habitat.
As heavy equipment removed accumulated sediment, workers uncovered something extraordinary: a massive fossil bone. Paleontologists and archaeologists were called to investigate, and it quickly became clear that this was not an isolated find.
Mammoth bones and tusk material were preserved in the sediments along the lake shore.
A preliminary excavation began that fall. Because winter was approaching and the fossils were exceptionally well preserved, much of the site was carefully protected and covered until a larger scientific excavation could be organized.
In 1994, Tolo Lake had been drained as part of a project to deepen and rehabilitate the lake for fish and wildlife habitat.
As heavy equipment removed accumulated sediment, workers uncovered something extraordinary: a massive fossil bone. Paleontologists and archaeologists were called to investigate, and it quickly became clear that this was not an isolated find.
Mammoth bones and tusk material were preserved in the sediments along the lake shore.
A preliminary excavation began that fall. Because winter was approaching and the fossils were exceptionally well preserved, much of the site was carefully protected and covered until a larger scientific excavation could be organized.
The 1995 Excavation
Researchers returned to Tolo Lake during the summer of 1995 for an intensive three-month excavation.
Scientists, government agencies, universities and more than 200 volunteers worked together at the site. Excavation areas were carefully mapped, photographed and documented while fossils were removed and protected for study.
By the end of the project, researchers had recovered more than 400 fossils representing at least 10 mammoths and three ancient bison.
Among the discoveries was the nearly complete skeleton of a large adult Columbian mammoth. Approximately 95 percent of the animal's skeleton was recovered, making it one of the most complete mammoths ever discovered in Idaho.
The mammoth is believed to have stood approximately 12 to 13 feet tall at the shoulder.
Yet scientists excavated only a relatively small portion of the lake bed.
Researchers concluded that the fossils recovered during the project likely represented only a fraction of the prehistoric remains preserved beneath Tolo Lake.
Researchers returned to Tolo Lake during the summer of 1995 for an intensive three-month excavation.
Scientists, government agencies, universities and more than 200 volunteers worked together at the site. Excavation areas were carefully mapped, photographed and documented while fossils were removed and protected for study.
By the end of the project, researchers had recovered more than 400 fossils representing at least 10 mammoths and three ancient bison.
Among the discoveries was the nearly complete skeleton of a large adult Columbian mammoth. Approximately 95 percent of the animal's skeleton was recovered, making it one of the most complete mammoths ever discovered in Idaho.
The mammoth is believed to have stood approximately 12 to 13 feet tall at the shoulder.
Yet scientists excavated only a relatively small portion of the lake bed.
Researchers concluded that the fossils recovered during the project likely represented only a fraction of the prehistoric remains preserved beneath Tolo Lake.
Grangeville's Mammoth Summer
The scientific discovery quickly became a community event.
Thousands of people came to Tolo Lake to see an active paleontological excavation taking place just outside Grangeville. Visitors watched fossils being uncovered, spoke with researchers and learned about animals that had lived on the Camas Prairie during the Ice Age.
More than a thousand schoolchildren toured the excavation during just the first two weeks of September 1995.
Local residents volunteered at the site, helped conduct tours and supported the excavation in numerous ways.
The excitement even inspired mammoth-themed T-shirts. One proclaimed:
"There hasn't been this much excitement in Grangeville, Idaho in over 10,000 years!"
Another local nickname captured the mood perfectly:
"Tolassic Park."
For one remarkable summer, a small Idaho community had a front-row seat to the Ice Age.
What Happened to the Mammoths?
Exactly why so many mammoths and other large animals died near Tolo Lake remains uncertain.
The lake was an important water source, and researchers have considered several possible explanations for the concentration of remains. Animals may have died from natural causes near the water, become trapped in unstable ground, or succumbed to disease, injury or old age.
Scientists found no evidence that the Tolo Lake mammoths were killed by humans.
What is clear is that the lake's sediments created conditions that preserved their bones for thousands of years.
The fossils recovered during the 1994 and 1995 excavations included mammoth tusks, humeri, femurs and other skeletal material, along with remains of the extinct ancient bison, Bison antiquus.
Many more fossils may still lie beneath the lake.
The Columbian Mammoth
The mammoths discovered at Tolo Lake were Columbian mammoths, Mammuthus columbi.
These enormous relatives of modern elephants lived across much of North America during the Ice Age. Adults could stand approximately 13 feet tall at the shoulder and weigh several tons.
Unlike the heavily furred woolly mammoth commonly associated with colder northern climates, the Columbian mammoth lived across more temperate portions of North America and may have carried considerably less hair.
They were herbivores that fed on grasses and other vegetation across the prehistoric landscape.
The Columbian mammoth disappeared near the end of the last Ice Age more than 10,000 years ago.
More Than a Prehistoric Site
Tolo Lake's story extends far beyond its mammoths.
Known to the nimíipuu, or Nez Perce, as Tepahlewam, the area was an important traditional gathering place where people harvested camas, traveled, met with neighboring bands and used the surrounding landscape for generations.
Tolo Lake later became associated with events surrounding the Nez Perce Flight of 1877.
Today, the approximately 36-acre natural lake is an affiliated site of Nez Perce National Historical Park and is managed by the Idaho Department of Fish and Game.
Its remarkable history spans thousands of years, from Ice Age mammoths to the enduring cultural history of the nimíipuu and the modern Grangeville community.
The scientific discovery quickly became a community event.
Thousands of people came to Tolo Lake to see an active paleontological excavation taking place just outside Grangeville. Visitors watched fossils being uncovered, spoke with researchers and learned about animals that had lived on the Camas Prairie during the Ice Age.
More than a thousand schoolchildren toured the excavation during just the first two weeks of September 1995.
Local residents volunteered at the site, helped conduct tours and supported the excavation in numerous ways.
The excitement even inspired mammoth-themed T-shirts. One proclaimed:
"There hasn't been this much excitement in Grangeville, Idaho in over 10,000 years!"
Another local nickname captured the mood perfectly:
"Tolassic Park."
For one remarkable summer, a small Idaho community had a front-row seat to the Ice Age.
What Happened to the Mammoths?
Exactly why so many mammoths and other large animals died near Tolo Lake remains uncertain.
The lake was an important water source, and researchers have considered several possible explanations for the concentration of remains. Animals may have died from natural causes near the water, become trapped in unstable ground, or succumbed to disease, injury or old age.
Scientists found no evidence that the Tolo Lake mammoths were killed by humans.
What is clear is that the lake's sediments created conditions that preserved their bones for thousands of years.
The fossils recovered during the 1994 and 1995 excavations included mammoth tusks, humeri, femurs and other skeletal material, along with remains of the extinct ancient bison, Bison antiquus.
Many more fossils may still lie beneath the lake.
The Columbian Mammoth
The mammoths discovered at Tolo Lake were Columbian mammoths, Mammuthus columbi.
These enormous relatives of modern elephants lived across much of North America during the Ice Age. Adults could stand approximately 13 feet tall at the shoulder and weigh several tons.
Unlike the heavily furred woolly mammoth commonly associated with colder northern climates, the Columbian mammoth lived across more temperate portions of North America and may have carried considerably less hair.
They were herbivores that fed on grasses and other vegetation across the prehistoric landscape.
The Columbian mammoth disappeared near the end of the last Ice Age more than 10,000 years ago.
More Than a Prehistoric Site
Tolo Lake's story extends far beyond its mammoths.
Known to the nimíipuu, or Nez Perce, as Tepahlewam, the area was an important traditional gathering place where people harvested camas, traveled, met with neighboring bands and used the surrounding landscape for generations.
Tolo Lake later became associated with events surrounding the Nez Perce Flight of 1877.
Today, the approximately 36-acre natural lake is an affiliated site of Nez Perce National Historical Park and is managed by the Idaho Department of Fish and Game.
Its remarkable history spans thousands of years, from Ice Age mammoths to the enduring cultural history of the nimíipuu and the modern Grangeville community.
The Mammoths Live On in Grangeville
After the excavation, Tolo Lake was refilled, protecting the fossil-bearing sediments that remain beneath its waters.
But visitors do not have to imagine what one of these enormous animals looked like.
A life-sized Columbian mammoth skeleton replica stands in Eimers-Soltman Park in Grangeville, next to the Grangeville Visitor Center at U.S. Highway 95 and North Pine Street.
Inside the Visitor Center, visitors can also see an actual mammoth humerus recovered from Tolo Lake.
Together, the fossil and the towering replica provide a connection to an extraordinary moment in Grangeville's history and to the prehistoric giants that once walked across the Camas Prairie.
After the excavation, Tolo Lake was refilled, protecting the fossil-bearing sediments that remain beneath its waters.
But visitors do not have to imagine what one of these enormous animals looked like.
A life-sized Columbian mammoth skeleton replica stands in Eimers-Soltman Park in Grangeville, next to the Grangeville Visitor Center at U.S. Highway 95 and North Pine Street.
Inside the Visitor Center, visitors can also see an actual mammoth humerus recovered from Tolo Lake.
Together, the fossil and the towering replica provide a connection to an extraordinary moment in Grangeville's history and to the prehistoric giants that once walked across the Camas Prairie.
From Grangeville, travel south on U.S. 95, turn west onto Tolo Lake Road, and continue approximately 4.2 miles to the lake.
Visit Tolo Lake
Tolo Lake is located approximately six miles west of Grangeville.
Today it is a peaceful destination for fishing, birdwatching, wildlife viewing and picnicking. Interpretive panels at the lake tell more of its natural and cultural history.
As you stand along the shoreline, remember that beneath those waters may still rest fossils from mammoths that walked the Camas Prairie thousands of years ago.
Continue the Story in Grangeville
After visiting Tolo Lake, stop at the Grangeville Visitor Center and Eimers-Soltman Park to see the Tolo Lake mammoth exhibit, view an actual mammoth bone and stand beneath the life-sized Columbian mammoth replica.
It is one of Grangeville's most unusual attractions and a remarkable reminder that sometimes the biggest stories are discovered right beneath our feet.
Tolo Lake is located approximately six miles west of Grangeville.
Today it is a peaceful destination for fishing, birdwatching, wildlife viewing and picnicking. Interpretive panels at the lake tell more of its natural and cultural history.
As you stand along the shoreline, remember that beneath those waters may still rest fossils from mammoths that walked the Camas Prairie thousands of years ago.
Continue the Story in Grangeville
After visiting Tolo Lake, stop at the Grangeville Visitor Center and Eimers-Soltman Park to see the Tolo Lake mammoth exhibit, view an actual mammoth bone and stand beneath the life-sized Columbian mammoth replica.
It is one of Grangeville's most unusual attractions and a remarkable reminder that sometimes the biggest stories are discovered right beneath our feet.