On October 14, 2010, a contractor felt a ka-chunk beneath his bulldozer. He stopped the engine. Climbed down from his high seat. And, what he saw changed the course of science and a whole community.
1958
Doug Ziegler decides to build an idyllic pond on his new mountain property. He has no idea the meadow he’s chosen was once the site of an ancient lake that attracted prehistoric creatures.
2008
The Town of Snowmass needs a reservoir to serve the growing population of the Roaring Fork Valley, so it purchases Ziegler’s pond and begins plans to expand it.
October 14, 2010
An excavator named Jesse Steele turns up a mammoth bone with his bulldozer. Realizing its importance, Gould Construction, his employer, halts excavation, and calls in scientists from the Colorado Geological Survey and the Denver Museum of Nature and Science.
November 3, 2010
More than 65 volunteers and scientists race to get bones out of the soil before winter closes in. Incredibly, on only the dig’s second day, they uncover Colorado’s first mastodon skull!
November 6, 2010
What was thought to be a mammoth tusk turns out to be prehistoric bison horns 6’ 4” long. More will be discovered, making Ziegler one of only three fossil sites with multiple specimens of this massive extinct bison.
November 14, 2010
Winter shuts down the dig. (It is an ice age, after all!) Tarps are spread over the site. And more than 600 bones are trucked to the Denver Museum of Nature and Science for further analysis
May 15, 2011
After months of planning, a larger crew begins a seven-week dig. It includes scientists. Specialists in sifting, documentation and plaster jacketing. Nine interns. And 107 trained volunteers.
May 24, 2011
With National Geographic cameras rolling in the background, the team participates in a livestream allowing 25 schools in 10 states to watch science happen in real time.
June 13, 2011
A dream comes true when site leader Kirk Johnson jokes, “Bring me the head of Ziggy the Sloth,” and local school teacher Chris Faison unexpectedly unearths the skull of a Jefferson Ground Sloth.
June 27, 2011
The largest mastodon of the entire excavation is uncovered when the team digs through a final patch of dirt that had been hidden beneath their porta-potties.
July 2, 2011
The dig is over. The crew is exhausted, proud, and ready to celebrate. And the fossils are on their way to the Denver Museum of Nature and Science for years of further study.
When you visit Snowmass, you’ll no longer hear the clopping of camel hooves or the bellows of Columbian mammoths. But you will see the same aspen, fir and oak species they saw. Because while most large prehistoric animals are extinct, 89% of the plant species still call these mountains home.
This Colorado icon cloaks the Rocky Mountains in greens and yellows every spring. And bur ... sts into oranges and reds every fall. One reason this species has lasted so many millenia? Its extensive root system helps it regrow quickly after fires.
This Colorado icon cloaks the Rocky Mountains in greens and yellows every spring. And bursts into oranges and reds every fall. One reason this species has lasted so many millenia? Its extensive root system helps it regrow quickly after fires.
The Quaking Aspen is a deciduous tree with three-inch green leaves that turn vivid shades of yellow in the fall. Each leaf trembles in the slightest breeze, which is how the tree gets its name.
Quaking Aspens usually grow between 30 and 50’ tall, but they can reach heights of 80’!
Quaking Aspens form clonal colonies that are all part of a single organism, sharing a root system that spreads underground. The largest colony is in Utah, weighs 13 million pounds, and spans 106 acres.
The Englemann Spruce is coniferous. It has short blue-green needles which do not fall off the tree seasonally like deciduous trees.
Englemann Spruce grow anywhere from 45 to 130’ tall. (See you on the gondola!)
Forest fires can be devastating to Englemann Spruce due to their thin bark, shallow roots and low branches.
The Gambel Oak is a deciduous tree. Its long, green leaves each have five to seven lobes. They fall off every autumn and regrow come springtime.
Gambel Oak grow 10 to 15 feet tall and spread their limbs, providing shade for the ground below.
The Rocky Mountain Fir is a coniferous tree with dark, blunt needles, each about an inch long. Their branches collect snow in the winter, and will also protect the tree from extreme wind or sun.
In the Rocky Mountains, these trees are often found at high altitudes, just below treeline, growing 60 to 100 feet tall.
The Jefferson Ground Sloth originated in South America and spread north. At one point, its domain ranged from coast to coast and as far north as the Yukon!
Today’s three-toed sloths are much smaller. And instead of the ground of Colorado, they live in the trees of Central and South America.
The Jefferson Ground Sloth is named for the man who first identified its fossils from a West Virginia cave – President Thomas Jefferson!
The Columbian mammoth was bigger than the American mastodon – by a lot. It could be up to four feet taller and 10,000 pounds heavier. Don’t pick a fight with a mastodon though! Its thick fur, stocky legs and burly body would have made it a ferocious opponent.
The American mastodon is a distant cousin of the modern elephant. Very, very distant. Their last common ancestor lived 27 million years ago!
Mastodon and mammoth tusks grow from the inside out. By looking at the rings inside, scientists can learn details about age, nutrition, and even the weather!
Long Horned Bison existed for almost a half-million years before going extinct 25,000 years ago. The fossils found at Ziegler Reservoir are likely about 120,000 years old.
You don’t have to stray far from the herd! The Long Horned Bison’s closest living relative is the American Bison, which have been reintroduced to Colorado in recent years. You may catch a glimpse of them on a drive through the Rockies.
This famous fossil found at Ziegler Reservoir is 6’ 4” long. But Long Horned Bison were mostly peaceful, grazing animals. The horns were probably used only for self defense.
Tiger Salamanders can survive on almost anything – insects, snails, slugs, frogs… and sometimes even each other!
Trick question! The Tiger Salamander species still exists today, mostly along the East Coast, but sometimes right here in Snowmass.
At the dig, some people had the job of “picker.” They wore magnifying goggles and sifted through piles of dirt, sometimes finding just one vertebrae or one tooth at a time!
The Columbian mammoth was bigger than the American mastodon – by a lot. It could be up to four feet taller and 10,000 pounds heavier. And while mastodons were browsers who could eat wood and shrubs, mammoths were grazers who subsisted mostly on grasses and plants.
Asian elephants, which once stretched from India to Borneo. Their population is endangered, though. There may be as few as 20,000 left in the wild.
Hold up, there! Wooly mammoths were a different species than Columbian Mammoths, existing in colder climates (and a few popular movies).
It’s hard to say just how many humps Ice Age Camels had. That’s because humps are made of fatty tissue, which decomposes quickly.
Asian camels of the genus camulus are a direct descendant of the Ice Age camel.
The Ice Age camel was a browser and grazer, subsisting on both woody vegetation and grass. Data from the fossils’ teeth showed they ate lots of leaves, too!
Mule deer are medium sized, around three feet high at the shoulder. They have a reddish-brown coat that gets darker in the winter, to help it blend in with its surroundings.
Trick question! Mule deer still exist today!
While black-tailed mule deer and white tailed deer have existed for millions of years, you can’t say the same about moose or reindeer. They’ve only been around a few thousand years.
There were no horses on the American Continent for thousands of years. Spanish conquistadors shipped them across the Atlantic Ocean in the 1300’s, during the conquest of the Americas.
The Ice Age horse’s closest cousin is the African zebra. (Now that’s a horse of a different color!)
Many large animals died off in North America about 11,000 years ago. The culprit might have been natural climate change, human hunting, or both!
80 million years ago
Two tectonic plates slide into each other, causing the Rocky Mountains to rise like ripples in a blanket, hundreds of miles away. The plates are still moving today, and the mountains are still rising.
2.6 million years ago
When was the most recent ice age? Trick question – we’re still in it! But it’s hard to tell. Unfortunately, our release of greenhouse gasses has disrupted natural climate cycles in ways we’re only beginning to understand.
140,000 years ago
A massive glacier slowly grinds crashes through the mountains, shaving off peaks and picking up rock debris. It forms the Roaring Fork Valley and the basin where Ziegler Reservoir lies today.
120,000 years ago
A warming trend brings melting ice and lush landscapes. American Mastodon, Latisfrons Bison and Jefferson Ground Sloth roam the terrain.
80,000 years ago
As the climate changes, so does the landscape. Over time, Mastodons are replaced by Columbian Mammoths. And the lake becomes a marsh, surrounded by some of the same evergreen and aspen species that thrive today.
21,000 years ago
A new glacier moves into the valley. It is much smaller than the one before, so instead of plowing through the ancient lake, it leaves the fossils undisturbed. New evidence from White Sands National Park suggests humans arrived in North America about the same time.
Present Day
Ziegler Reservoir is viewable from several of the day hikes around Snowmass including the Discovery Trail. And it provides water for the people who call this special valley “home.”
It didn’t take a major event to preserve more than 5,000 fossils in this one location. Instead, they accumulated slowly over time. Some were deposited by glaciers. Some were brought by mudslides. Others belonged to animals who got stuck in the marsh. These fossils waited underground for thousands of years, perfectly preserved, ready for scientists to uncover.
One of the oldest fossils found at the Snowmass site was actually near the top, hiding just under the Port-a-potties!
The original mammoth discovered by Jesse Steele was named by an online poll.
Snowmass is the highest elevation at which this species has ever been identified.
The American Mastodon was unearthed in the depths of Zeigler Reservoir.
