This South Dakota Wilderness Holds 37-Million-Year-Old Fossils & Doubled as a NASA Mars Training Ground

Badlands National Park, South Dakota

Most people driving through South Dakota don’t expect to find ancient seabeds and fossil beds. But that’s exactly what the Badlands are – a place where you can watch geology happening and spot traces of prehistoric animals in the same afternoon. Here are some of the most interesting facts about this beautiful, harsh landscape.

Ancient Fossils in the Park

The Badlands contain one of the best fossil sites from the Oligocene period, which was 23 to 35 million years ago. Over 250 vertebrate species, including both herbivores and carnivores, have been discovered in the park.

Heavy rains often wash away rock layers to reveal new fossils. Scientists have found complete skeletons of ancient three-toed horses, sheep-like creatures called oreodonts, early rhinos called titanotheres, and giant pig-like entelodonts.

Visible Layers of Earth’s History

The colored bands in the park’s rock walls show 75 million years of Earth’s history. The black layers at the bottom formed from an ancient seabed during the Cretaceous Period, while yellow stripes show where rivers once flowed.

The red and pink layers in the Sharps Formation are primarily composed of mudstone and sandstone, typical of river and floodplain environments. Each year, about an inch of rock erodes, showing more of what lies beneath.

Astronaut Training Site

NASA chose the Badlands for Apollo astronaut training because parts of it look similar to the moon’s surface. The Sage Creek Wilderness Area has deep craters, sharp spires, and empty plateaus that helped astronauts prepare for lunar missions in the 1960s.

Scientists still study these formations to better understand how similar features form on other planets. The park’s rugged landscape continues to help researchers learn about space exploration.

Home of the Prairie Dog Community

Roberts Prairie Dog Town is one of the largest black-tailed prairie dog colonies in the Badlands.

These social animals have built an underground network of tunnels 3 to 14 feet deep, with special rooms for sleeping, raising young, and storing food. Their burrows provide homes for other animals like burrowing owls, swift foxes, and black-footed ferrets.

By eating grass and other plants, prairie dogs help maintain the prairie’s natural balance.

Record of Climate Changes

The rock layers in the Badlands tell the story of ancient climate changes. Each layer holds clues about what the environment was like when it formed, from the Brule Formation’s (30–34 million years old) cool, dry climate with shrublands and woodlands to fossilized root casts suggesting wetter conditions.

The Sharps Formation (28–30 million years old) indicates a cooler, drier savanna-like environment with volcanic ash deposits.

Perfect Location for Stargazing

The Badlands has some of the darkest night skies in the United States, ranking as Class 2 on the Bortle Scale. The park sits over 3,000 feet above sea level, far from city lights, which makes it perfect for seeing stars.

On clear nights, you can see more than 7,500 stars or spot the Andromeda Galaxy, which is 2.5 million light-years away. Clean air and dark skies make it possible to see the full arc of the Milky Way without a telescope.

Return of the Bighorn Sheep

Bighorn sheep are back in the Badlands after disappearing in the early 1900s. Starting with just 22 sheep in 1964, the population has grown to over 200 as of 2021.

Translocations from other states (like New Mexico and Montana) have occurred to bolster genetic diversity. These amazing animals can climb 60-degree slopes and are often seen in the Pinnacles area.

Since then, they’ve helped restore the ecological balance by grazing on native vegetation.

Plants Used for Traditional Medicine

The Badlands plant list includes 444 species, with graminoids (grasses, sedges, rushes). Native American communities used their chemical properties to survive the harsh environment.

The Medicine Root Trail features Barr’s milkvetch (Astragalus barrii), a rare plant that is not commonly encountered.

Common medicinal plants include purple coneflower (Echinacea angustifolia) for immune support, and wild bergamot (Monarda fistulosa), used to treat colds and fevers.

Sound Effects in the Rock Formations

The rock formations in the Badlands create unusual sound effects. Some canyons can carry sounds for over a mile, while winds blowing through the spires make different whistling sounds.

Today, you can hear these sounds along with natural prairie noises like rustling grass and bird calls. Badlands National Park also utilizes acoustic monitoring to study bat populations, capturing extensive ultrasonic calls used for echolocation. ​

Evidence of an Ancient Ocean

Seventy million years ago, the Badlands were underwater, covered by the Western Interior Seaway. The Yellow Mounds Formation, derived from weathered Pierre Shale marks a transition from an ocean floor to the rugged landscape we see today.

You can find fossils of sea creatures throughout the park, including three-foot-wide ammonite shells and mosasaur bones (apex predators measuring over 50 feet long).

Echoes of a Rich Heritage

The Lakota Sioux, specifically the Oglala and Brule bands, have a profound historical connection to the Badlands.

Over 300 archaeological sites have been identified within the park, yielding artifacts such as stone tools, pottery shards, and remnants of ancient campfires.

The park encompasses Stronghold Table, one of the last known sites where the Ghost Dance—a spiritual movement among Native Americans—was performed in 1890.