A Prehistoric Surprise: The Mammoth Site of Hot Springs, South Dakota

Sometimes the best discoveries come when you least expect them. We had no plans to visit the Mammoth Site in Hot Springs, South Dakota—until a National Park Ranger casually mentioned it in passing. With a car full of curious kids and a little extra time, we decided to take the detour. It turned out to be well worth it.

This isn’t just any fossil site. The Mammoth Site holds the largest single deposit of mammoth remains ever found in North America. And unlike most paleontological sites where bones are removed and relocated, here you get to see them in situ, still lying where they were uncovered. Bones rest at different levels, showing how they accumulated over an astonishing 50,000 to 100,000 years.

The cause? A single natural trap. Around 200,000 years ago, a sinkhole formed with slippery shale edges. Mammoths, likely drawn to the water below, would wander in and then find themselves unable to climb out. Over time, layer upon layer of mammoths met their fate in the soft mud.

James was quick to remind us: mammoths are elephants! The Columbian mammoth, with its towering size and resemblance to a super-sized African elephant, stole the show. We were especially excited to see the comparison to the much smaller pygmy mammoth, which only lived on California’s Channel Islands—where we had just been a few weeks earlier.

What makes these bones even more special is their state of preservation. They are not fossils in the traditional sense. Unlike dinosaur bones that have mineralized into rock, these mammoth bones remain actual bone, preserved by time and sediment.

Interestingly, this part of South Dakota never hosted dinosaurs (as far as we know). During the dinosaur age, it was underwater, part of an ancient sea. While marine reptiles like mosasaurs ruled those waters, the land only later became home to Ice Age giants.

We also learned about some of the other enormous creatures that once roamed this area: the giant short-faced bear, towering over today’s grizzlies, and the giant ground sloth, which could reach the height of a small building. As recently as 10,000 to 20,000 years ago, these creatures walked these plains.

Even more intriguing were remains of mammoths from around 11,000 years ago showing marks that suggest they may have been hunted or scavenged by early humans. There’s no written record, so we can only imagine how humans interacted with or contributed to the decline of these giant mammals.

Standing at the site, we considered how the Columbian mammoth is believed to have consumed 300 pounds of vegetation a day. With our drives through the nearby Badlands and prairie grasslands, it was clear this landscape has changed dramatically. These once-lush plains could sustain herds of gigantic mammals in ways hard to imagine today.

The Mammoth Site wasn’t on our original plan, but it ended up being well worth the stop. If you’re near the Black Hills, detour to Hot Springs. It’s a one-of-a-kind chance to step into an Ice Age graveyard, wander among giants, and reflect on a South Dakota that looked very different from today.