Persistence Yields Fossils, Holds Mystery

Jun 19, 2015

Sharon Holte a PhD Candidate at University of Florida digs for tiny fossils inside Persistence Cave at Wind Cave NP.
Credit Charles Michael Ray

Persistence Cave in Wind Cave National Park is yielding a trove of fossils that are shedding light on the distant past in the Black Hills.

The deeper parts of the cave may also contain large caverns yet to be explored.

But, anyone who wants to dig fossils inside Persistence Cave is going to get muddy.  

After scaling down a hole with the aid of a few knotted ropes researchers belly crawl into a tight passageway.  One of them is  Sharon Holte, a PhD Candidate at University of Florida.  Holte spends long hours covered in mud and crouched into a tight space digging for tiny bits of fossils.      

“This is all in-filled so all of this is very bone rich throughout this entire area,” says Holte.

 Turns out the dirt in this cave is full of bones. The fossils near the entrance of the cave include  long extinct horses and pigs.  The cave also has Pika fossils, these tiny mammals love the cold.  They lived in the Black Hills during the last ice age.  Today, they survive in the alpine areas of the Northern Rockies.  The cave even has bones of buffalo that could have been brought in by predators looking for a safe place to eat or store their catch.   

Holte points down to the mud floor.  “That is all full of bone,” she says.  “If you spend eve a couple of minutes looking down at it you should be able to see little bone pieces,” she adds.

So far researchers have found more than 25 different species.   To study the fossils in this cave researchers have set up a bucket brigade of sorts. Someone like Holte fills bags in the bottom of the cave and the dirt is passed up the chain to the surface where it’s brought back to a lab where an expert like Sandra Swift  looks for tiny bits of fossils.

“I’ve been doing this for about 30 years now, so I can sort out bat, shrew, mole, pack rat whatever the animal is,” says Swift the collections manager at East Tennessee State University.   She’s also working with the Mammoth Site in Hot Springs on this dig at Wind Cave.  Swift won’t run out of work anytime soon…  this kind of research is tedious… First Swift washes out the mud from the bags of dirt that come in from the cave dig, the remaining material looks like sand, which she goes through teaspoon by teaspoon under a microscope.

“A gallon bag of sediment will take me about 40 hours, so yea it’s very slow-but the information we get is amazing," says Swift.

One bit of new information uncovered in this dig are Black Hills Pikas that lived here during the last ice age.

“Pika today, closest would be the Bighorn Mountains what’s that 200 miles,” says Dr Jim Meade with the Mammoth Site and East Tennessee State university.

This summer Mead is leading the effort to study the fossils in Persistence Cave.  Mead notes that fossils like Pika tell a story about the past climate in the Black Hills.  

“You know this place hasn’t always been what it is today,” says Mead.

Pikas love the cold they get stressed out anytime the temperature gets above about 70 degrees.   Today they only exist in high mountain areas,  basically they are holding out on the tops of icy mountain peaks.  But, during the past ice age they had a much bigger range.  

Mead says the Pika fossils, and the plant fragments found here at Wind Cave National Park lend insight into modern land management and climate change.  

“Park Service in many ways by definition says we take a snapshot and we preserve the park whichever park is it that way… but  climate says I can change whenever I want to and I can go in cycles.   So the park Service has a huge task to figure out, what is natural?  What is going to change in cycles?  How do we react to it?   says Mead.

Meade says understanding the way the climate changed in the past helps the Park Service plan for the future.  He says the digging in Persistence Cave may continue for the coming weeks with the research extending into the next few years. 

Cavers are standing by, waiting for the excavation to end so they can begin to explore the deeper passageways that may be hiding below. Like its neighbor, Wind Cave, Persistence Cave is also blowing air.  This is an indication there are extensive caverns below.  So, its possible fossils aren’t the only secret this cave has to reveal.