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Unearth the Mysteries: Journey into the Hidden World of Mammoth Fossils in South Dakota

As an paleontologist, that scene makes me giggle every time I see it, and on a trip to the Mammoth Site of Hot Springs, South Dakota, will show you why.

Today, the biggest living creatures roaming the Black Hills are bison; they’re plenty wild and woolly, but these hills used to be the stomping grounds of something even woollier: mammoths. They were drawn to the area’s natural hot springs found in the area.

Unfortunately, one of these spring-fed ponds turned out to be a death trap for more than 60 male mammoths; once they entered the water, the sides of the sinkhole were too slippery for such large creatures to climb back out. Over time, their skeletons piled up and the shaft of the sinkhole eventually filled in.



The mammoths wouldn’t see daylight again until 140,000 years later, in 1974, when a construction worker linking the ground for a housing development hit a tusk with the blade of his machine. The Mammoth Site has been an active dig ever since, one of the few places in the U.S. where you can follow a fossil’s path from the ground to the preparation lab to the museum floor, all within the same building.

Venturing into the parking lot, I’m greeted by a life-sized reconstruction of one of the site’s namesakes, a Columbian mammoth, raising its trunk above the museum’s welcome sign. The town of Hot Springs has fully embraced the local extinct wildlife.

The restaurant next to the museum is named Woolly’s, in honor of the smaller species of mammoth found next door, and there are also a surprisingly large number of visitors on the site’s morning tours for a day in late September.



As I enter the room that houses the dig itself, I’m struck by the height of the excavation. It takes a pretty big hole in the ground to trap upwards of 60 male mammoths (mostly the larger Columbian species, though they’ve found a couple of woolly mammoths too), but hearing about it and seeing it in person are two different things.

The way the bones have been excavated has left dramatic sheer walls and flat terraces in the yellow-tan earth, on which light brown mammoth skulls sporting huge tusks sit like statues on pedestals. The bones are arranged to give both depth and perspective to the yellow-tan earth, on which light brown mammoth skulls sporting huge tusks sit like statues on pedestals. The bones are arranged to give both depth and perspective to the yellow-tan earth, on which light brown mammoth skulls sporting huge tusks sit like statues on pedestals. The bones are arranged to give both depth and perspective to the yellow-tan earth, on which light brown mammoth skulls sporting huge tusks sit like statues on pedestals.



Descending into the stairs from the main wooden walkway that encircles the active part of the dig to stand on a fenced-in platform on the level of one of the deepest fossilized remains, I’m keenly aware that there are likely many more bones of Ice Age animals beneath my feet. Along with the famous mammoths, many other species have been found here, including llamas, camels, and the giant short-faced bear (Arctodus simus).

The site’s geologists have figured out that the sinkhole was originally about 65 feet deep. The dedicated crew of paleontologists, interns, and volunteers working at the site have only excavated about 20 feet of that. And, unlike the Jurassic Park paleontologists, they’re not doing it with just paintbrushes and bare hands.

On the day of my visit, a group of adult volunteers sits in the less-excavated half of the fenced-off area of the boneyard, gently tapping away with hammers and small chisels, scraping with trowels, and scooping the loose sediment into buckets. One of the last glamorous parts of a thorough excavation is screen-washing, where bucket after bucket of dirt is reduced through a screen until only small bits of rock, bone, and teeth are left behind. What remains is then picked through for tiny fossils—rodents and rabbits—that met their end in the sinkhole.



Some of this picking happens downstairs, in the Mammoth Site’s fossil preparation lab. A short elevator ride down to the museum’s lower floor reveals the parts of paleontological mysteries most people don’t think about when they see a beautifully completed skeleton in a museum. After leaving the elevator, I’m greeted by a wall of windows.

Here, visitors can peer into the lab as bones of prehistoric creatures are carefully cleaned and glued back together, like putting together a puzzle. Glass cabinets house the finished products—carefully crafted replicas (called casts) of the bone, which are often what ends up in museums. Fossils are fragile and irreplaceable, so it’s safer to work with the casts.

The people who work in these spaces are the unsung heroes of paleontology, painstakingly bringing ancient bones back to life. While a lot of mammoths are starting to pull back the curtain on what it takes to prepare a fossil when it comes to the field by building these kinds of “fishbowl” labs, the Mammoth Site is a rare destination because the fossils are being uncovered and prepared right back to back within the same building.



Heading back upstairs, I see the work of the site’s preparators in the museum’s more traditional gallery space, where mounted mammoths and replicas of hunt-made casts of mammoth bones and faux-fur await. Half of this space is dedicated to ancient life in the Black Hills and surrounding areas, but the other half is all about fossil elephants and their relatives.

Fragments of mummified tissue from mammoths found in the Siberian permafrost fill the cases on one wall. Mounted skeletons include a Channel Islands pygmy mammoth, a dwarf descendant of mainland Columbian mammoths.

The Mammoth Site is a local treasure of international scientific importance, and I leave with a sense that the residents of Hot Springs get to live with these fossil riches so close at hand. But I’m also reminded that the traces of prehistoric life are everywhere—even if they’re usually less dramatic than a sinkhole full of mammoths.



The Mammoth Site of Hot Springs, South Dakota, is open year-round (except for New Year’s Day, Easter, Thanksgiving, and Christmas). Hours vary by season. The site only offers guided tours, so be sure to arrive early to secure your spot before the last tour begins.