From the Depths of an Indiana Cave: A Fossil Treasure Trove

Around perhaps 25,000 years ago in Southern Indiana, an injured Dire Wolf made its way into a cave and never came back out. With three good legs and one that had been out of socket for a year or so, the wolf crawled through the smaller spaces and eventually—whether through an accidental fall or otherwise—landed at the bottom of a deep pit. It was trapped.

Ron Richards, Senior Research Curator of Paleobiology at the Indiana State Museum, and his crew discovered its skeleton after digging in that particular room for 3 or 4 seasons.

Ron took that set of bones to pathologists for more information. However long that injury was sustained, and it was not a short amount of time, that wolf was a survivor. They determined the one leg probably didn’t touch the ground, but that it could probably still run using the other three.

“What normally is a circular ball-joint on his thighbone was flattened on one whole side,” Ron explained in a phone interview.

“I think that probably affected his ability to back out. Maybe he smelled some rotting carcass smell or something, got too near and couldn’t back out, and probably went over the top [of the pit.]”

A reconstruction of that event, complete with an actual cast of that specific room in the cave, can be seen at the Indiana State Museum today.

What may not be apparent was the work involved in creating that cast.

The word “cave” might invoke images of enormous open spaces underground. This is not at all that kind of cave. Not at the initial opening, nor at any space within as one moves deeper inside.

“Years ago, you had to go into a belly-crawl,” Ron said of the entrance, “but now we’ve moved through it so much, we can do a hands-and-knees crawl.”

They built a platform to work above water pooling at the bottom of the pit, and—in order to keep the walls dry for rubber molds—they used blowtorches. Ron, cave dig crewmembers and people from RCI (Research Casting International) worked together on the beginning stages of the room’s cast. The finished product was done at RCI headquarters in Ontario.

RCI - Dire wolf replica

[Image of the cave cast and wolf replica, http://www.rescast.com, by Research Casting International for the Indiana State Museum]

Nothing done in that cave is an easy process.

When Ron first began digging in that cave, he said, “I thought it would take 9 people 9 days, and we could finish the project.”

That was in 1987. The dig was prompted by the discovery of a single peccary bone.

Ever since, for approximately two weeks each year, Ron and his crew have returned to dig.

“[It was] the first big cave dig we had done,” he continued, describing that first year. “We’d done a couple of mastodon digs at the time, but we really had no money for the budget. There was nothing there. We had no trained staff. We had almost no equipment.”

“I remember pulling this together, pulling different people from different sections of the museum.”

And when it came to potential funding for this excavation, Ron recalled that he was asked, ‘Can’t you do this another time?’

“I didn’t know what to say,” he admitted, “so I didn’t say anything. The next day, we got the gear loaded, and we headed down for the cave. We just did not look back!”

“As it worked out, we dug, we found more bone: parts of little peccaries, parts of big peccaries, and other animals that no longer occur in the region.”

Peccaries are relatives of modern pigs, but instead of upper canine teeth that curve up—as in modern hogs—their teeth “drive straight down like daggers,” as Ron explained. Today, modern peccaries live within the Southwest United States, as well as in Central and South America. But during the Ice Age, peccaries were common in Indiana and Eastern U.S.

Peccary Fig 02  iceage13a upgraded

[Pleistocene peccary by Karen Yoler, image courtesy of Ron Richards, the Indiana State Museum.  Per Ron Richards: “This image is artist Karen Yoler’s  concept of what the peccary looked like.  We did drop off the larger dew claws on the front legs and added a little more canine tooth size and gave it a more perpendicular orientation.”]

 

[Angry javelina–or collared peccary–close up. Javelina go by many names such as wild pig,boar,etc.; image and caption from Getty Images.]

Working deep in the cave initially, the crew created a system that they continue to use, with some improvements, to this day: some people dig in the cave and place the soil into buckets; other people haul the buckets out of the cave and bring them down to a stream; still others screen the soil for fossils.

All of the data is recorded; all of the soil is screened.

“Above you are big spiders—lots of cave spiders and cave crickets. They don’t bother you, but some people get the heebie-jeebies, you know? I mean, you look up, and there [are these] massive things moving around,” he said and chuckled.

In recent years, they’ve developed what Ron refers to as “tramways,” 60-70 feet of ramps created by parallel boards with cross slats. Tramways—some with rollers—help bring the buckets out of the entrance to the cave and down the hillside.

ISM - Cave with tramway

 

[Digging…with the tramway in position for hauling buckets of sediment out, image courtesy of Ron Richards, the Indiana State Museum.]

To help carry 15-20 buckets at a time down to the spring to be screened, they employ an ATV with a tractor.

“[From all of the] tons of soil that gets screened,” Ron stated, “[there remains some] soil that’s left with small bones. We bag that out, bring it back to the museum, and then they rescreen it and clean it. And then–spoonful by spoonful–they go under the binocular microscope, and they pick out all the small bones and teeth.”

His crew is a dedicated group: leaving their hotel rooms at 8am and working throughout the day—with a short break for lunch–until 5pm (or later if the weather holds). Ideally, there are nine crewmembers per season, but they have done it with less people. Digging has sometimes required breaking rock, so among the many tools used are sledgehammers and chisels.

ISM - Cave digging

 

[Digging for peccary bones, image courtesy of Ron Richards, the Indiana State Museum.]

 

Over the years, the cave rooms have gained descriptive names: the Peccary Room, for example, the X Room, and the Bat Room.

The “Microfauna Room” was named after the large amount of small bones they found when they began digging through the top layers of soil and rock. This is where the aforementioned Dire Wolf was discovered.

“Near the bottom of that room, down at the 25,000-yr level,” Ron explained, “we began to get fairly complete skeletons of things like Dire Wolf, Black Bear, an otter, a snowshoe hare, a lot of small shrews and mice.”

“We really believe that those animals fell in this pit. They dropped, and they went down about 15-20 feet. I think most of the time it was probably full of water.

“It’s just a lonely place to be. Whether they could stand at the bottom, I don’t know. But there’s no way out.

“There [was] enough mud washing in from the ceiling of that room that they were buried under real fine sediments. And that preserved them very well.”

Some of the fossils discovered have been both remarkable and rare. A tapir tooth—only the second to be found in the entire state of Indiana—was found in the cave. Several beautiful armadillo (Dasypus bellus) plates [osteoderms] have been discovered have been discovered (that is the actual name; ‘beautiful’ is not necessarily a description). Ron painted a picture of this by saying, “When one animal dies, there’s about 3,000 plates that disintegrate and go everywhere, like little dominoes.”

“Two years ago,” he said, describing the ‘Twilight Room’, “we started finding some articulated peccary skeletons.”

“Deep in the cave we didn’t find a lot of that. The bones would be disturbed, and you could just see sort of a jumbled mass that had been moved by water, by gravity, [or] by other animals.”

“In this room, we found things that were articulated, feet in place, all of the little toes in place. Really unusual.”

The earliest fossils found were parts of a giant land tortoise, a species that cannot live in cold climates. Finding this indicated that the area, at that time, did not freeze.

Also found were fossils of a pine marten, a species that, conversely, lives in Northern climates today.

And as for peccaries, Ron estimates that they have found the bones of approximately 650 individuals. They determined this number by by counting the total number of large, pointed canine teeth and dividing by four.

ISM - flat-headed peccary

[Bones & skull of the flat-headed peccary, image courtesy of Ron Richards, the Indiana State Museum.]

“So the question is then: did they live here? Or did they all have a misfortune and die here? It’s a little of both, but it’s mainly that they probably inhabited this cave and rock shelter for most of that time period.”

Ron mentioned that a number of the fossil discoveries in the cave are new to him.

So how does one identify unfamiliar fossils?

“We have a general reference collection of modern bones,” he replied, “and there is a big collection at Indiana University, Bloomington that I had become very familiar with in the 1970’s and 1980’s.”

He went on to explain that he referenced available literature and visited other museum collections.

“I had written correspondence,” he continued, “and the mailing of specimens with several experts in the eastern United States. My foremost ‘mentors’ were Dr. Russell Graham (then The Illinois State Museum), and the late Dr. J. Alan Holman (The Museum, Michigan State University), but I also had open correspondence with the late John E. Guilday (Carnegie Museum of Natural History), the late Dr. Paul W. Parmalee (The McClung Museum, University of Tennessee), Dr. Holmes Semken (University of Iowa) and the late Wm. R. Adams (Zooarchaeology Laboratory, Indiana University).”

“Everything [is] dug in square units,” he said. “We have thousands of these units. We can show the distribution and abundance of anything that pretty much died in that cave for thousands of years.”

And the work is hardly done. Ron estimates that the digging portion may be completed within the next 5 seasons (5 years), but the analysis of the immense amount of fossils has yet to begin.

“We’ve got probably 30 radiocarbon dates from the cave. Every year, we get one or two more.”

Ron explained that the cave has, so far, produced “probably 7,000 small plastic boxes of small bones, and 2,000-3000 larger containers of larger bones.”

“It’s my job to identify those. But, you understand,” he said, laughing, “life is short. I could spend all my time, day and night, just working with that alone. It’s an immense project.”

————–

Many, many thanks to Ron Richards, whose generosity astounds me.  I am profoundly grateful for his time, his patience with my “volley of questions” and his fascinating descriptions.  It is always a pleasure and an honor connecting with him!

A sincere thank you to Bruce Williams for prompting this post!

**The name and location of this cave were intentionally left out for security reasons.

[Image of the Indiana State Museum, Getty Images]

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3 thoughts on “From the Depths of an Indiana Cave: A Fossil Treasure Trove

    1. Thank you! Ron Richards compiled a great list of what was found in the cave. I reviewed it, but I didn’t see any squamate fossils on it (all mammalian outside of the giant land tortoise). I’ll see if I can find out anything more!

    2. Here is what the amazing Ron Richards said, when asked: “Yes, there are snake bones, and some lizards in some of the units. We’re still in the field recovery phase, and cataloguing and identifications have been minimal. Identification clusters are moving slowly, too slowly to even consider separating out any particular groups for identifications. The unified cataloguing system for microfauna is not at all in place. Without cataloguing, it is just too early and to risky to move any specimens out from their excavated units. And, at the moment we are cataloguing and identifying remains from…another peccary cave. So, I wish I had a better answer for you. There are large timber rattlesnake bones, but other than being quite visible I have not looked at any of the small snakes in detail, though small natricines (Thamnophis) have been apparent to me.”

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