The Mammoth Site
1800 US-18, Hot Springs, SD
Hot Springs, SD
An indoor dig built over an ancient sinkhole where dozens of mammoths were trapped, their bones still lying where they fell more than twenty-five thousand years ago.
In 1974, workers leveling ground for a housing development in Hot Springs turned up a huge tusk, and the bulldozers stopped. What they had found was a fossil bonebed of extraordinary richness, an ancient sinkhole that, tens of thousands of years ago, had trapped and killed a great many mammoths and other Ice Age animals. Rather than dig the bones out and ship them away, the community built a structure over the whole site and kept it intact.
The result is the Mammoth Site, an indoor excavation where you walk a ramp above the dig and look down on real mammoth bones lying just as they came to rest, alongside scientists still carefully uncovering more. It is one of the largest concentrations of mammoth remains found in place anywhere in the world, and a rare chance to stand over an Ice Age scene frozen in the ground.
What Guests Love
- Seeing real mammoth bones lying exactly where they were found, under one roof
- Watching an active excavation still yielding new fossils
- A climate-controlled dig that makes it an ideal any-weather stop
- The sheer strangeness of a prehistoric death trap preserved in place
Worth Knowing
- This is a working dig as well as a museum, so what is exposed changes over time
- It is fully indoors and climate-controlled, a good rainy-day or winter option
- It pairs naturally with Wind Cave National Park just up the road
- Hot Springs is a good southern-Hills base, quieter than the busy central towns
Details
Hot Springs, SD
Learn about The Mammoth Site
The discovery
The site came to light in 1974 during earthmoving for a housing project, when a heavy blade sheared through a mammoth tusk. Recognizing the find's importance, work halted and scientists were called in, and it quickly became clear that this was no single skeleton but a dense bonebed of many animals.
Rather than excavate the bones and remove them, the decision was made to preserve the deposit where it lay and build a protective building over it, so the fossils could be studied and displayed in place. That choice, driven by local supporters and researchers, is what makes the Mammoth Site so unusual: it is the dig itself, roofed over and open to visitors, not a set of bones carried off to a distant museum.
The ancient sinkhole
The trap was a sinkhole. Long ago, warm groundwater dissolved a cavity in the underlying rock, and the roof collapsed to form a steep-sided pond fed by a spring. Mammoths and other animals coming to drink slipped down the slick banks, could not climb out, and died, one after another over many centuries, their bodies settling into the accumulating sediment.
That sediment sealed and preserved the bones remarkably well, holding them in the positions where the animals came to rest. Radiocarbon and other dating place the deposit deep in the last Ice Age, and the fine layering of the pond fill lets scientists read the site almost like a slow-motion record of a long-lived natural trap.
What the bones reveal
The site is dominated by mammoths, both the Columbian mammoth and, more rarely, the woolly mammoth, and nearly all of the identifiable individuals are young males, a pattern researchers link to the risk-taking behavior of adolescent bulls that likely ventured to the treacherous pond alone. Alongside them lie other Ice Age creatures, from a giant short-faced bear to camels, llamas, wolves, and small mammals.
Because the excavation is ongoing, the Mammoth Site is a working research center as well as a museum, and its scientists continue to uncover new bones and study the ecology of the Ice Age plains. Visitors walk an elevated path above the active dig, seeing paleontology as it actually happens rather than as a finished display.
Visiting and the southern Hills
Because the entire site is indoors and climate-controlled, the Mammoth Site is a comfortable stop in any weather, a genuine advantage in a region of hot summers and cold, snowy winters. It makes an especially good rainy-day or off-season option when outdoor attractions are less inviting.
The site sits at Hot Springs, a graceful sandstone town at the quieter southern end of the Black Hills. Wind Cave National Park, with its rare boxwork formations and roaming bison, is just up the road, and the warm mineral waters that gave Hot Springs its name are nearby, making the southern Hills a rewarding and less crowded base.
Closest Boutels
The closest Boutel™ stays, so you can turn this stop into an overnight. Each is an independently owned, editorially selected place to stay.
Things to Do Near Hot Springs
Hot Springs
About 2 miles
A handsome sandstone town built around warm mineral springs, with historic architecture and a warm-water indoor plunge.
Wind Cave National Park
About 12 miles north
A national park protecting one of the world's longest caves, famous for delicate boxwork, above a prairie of bison and elk.
Evans Plunge
About 2 miles
A historic indoor spring-fed swimming pool in Hot Springs, filled by warm mineral water that flows year-round.
Wild Horse Sanctuary
About 15 miles south
A large refuge where herds of wild mustangs range across the canyons and grasslands of the southern Hills.