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A Pleistocene pit-stop: the Barnosky lab excavates Natural Trap Cave, Wyoming

You might think that an 85-foot-deep hole where a bunch of horses, wolves, camels, elephants, and plenty of other animals accidentally plummeted to their death over tens of thousands of years would have enough red flags to make going into it yourself sound like a bad idea. But what if these unfortunate critters could tell you what their life was like and how they died? What if they could give you a warning about their death in a warming world after the last ice age and what it means for life in a warming world today? And, most importantly, what if you could fall and climb back out very slowly on a controlled rope system with an expert team of cavers and paleontologists? This past summer we decided to do just that: Barnosky lab members Eric Holt and Nick Spano with alums Susumu Tomiya and Jenny McGuire joined a crew led by Julie Meachen (Des Moines University) to descend into this “Natural Trap” Cave, excavate ice age mammal fossils, and help advance our understanding of how life responds to climate change, all without contributing any extra bones.

Natural Trap Cave is a 12-foot wide by 85-foot deep hole at the top of a hill in the Bighorn Mountains on the Wyoming side of the Montana border. The entrance to the cave is difficult to see coming down from the ridge of the hill behind it, so it’s not surprising that many Pleistocene ‘megafauna’ (animals bigger than 100 lb. or 45 kg)  accidentally fell to their demise here over tens of thousands of years ago. As they fell into Natural Trap Cave, their bones formed a well-stratified and mostly undisturbed pile that has become internationally renowned since the 1970s for its paleontological significance. The cave had been closed by the Bureau of Land Management (BLM) for over 20 years to protect the fossils from theft. However advances in ancient DNA research and growing interests in what Pleistocene extinctions could tell us for conservation prompted it to be reopened by Julie Meachen’s group for further research. This site is ~42 °F at ~98% relative humidity year-round, making it an ideal refrigerator for extracting 30,000 year-old genetic material. Geographically, it is located just south of a gap that existed between the Laurentide and Cordilleran ice sheets in central North America at the last glacial maximum (LGM) ~22,000 years ago. The ice-free corridor extended all the way up to Alaska and provides a unique opportunity to investigate continental migration dynamics, population genetics with ancient DNA, and climate-driven community changes.

This past summer, Eric and I (Nick Spano) drove 18 hours from Berkeley, CA to join a volunteer crew of paleontologists and cavers led by Julie Meachen at Natural Trap Cave in Wyoming. To enter the cave, each person needs to rappel down a rope hanging 85 feet down into the cave. Even if you claim to be unafraid of heights, the first descent is still slightly nerve-wracking. Stepping backwards off of the cave’s rim into a black pit with only a constellation of faint headlamps at the bottom can be a little unsettling. Plus, easing your grip on the rope here to let out slack takes a couple days to become comfortable with.



Eric Holt descending down a ladder towards the ‘edge of no return’.

Once you start the descent through increasingly colder temperatures, a council of packrat (Neotoma) middens along an inner rim welcomes you to the cave. After the initial shock of dangling passes and your eyes adjust to the low light, you get a sense for just how open and surreal the bell-shaped chamber is. I could only imagine what it must have been like for whole bison, horses, and wolves to fall that far down as I gracefully descended to the cave floor. Because we were searching for fossils of all sizes--from bison to mice teeth--we had to look carefully while excavating. That said, a fossil would pop out of the sediment about every ten minutes, which kept things pretty exciting.

horse cannon bone

Horse cannon bone found by Nick Spano. Dental pick for scale.


Eric Holt carefully excavating a bison dentary to be field-jacketed.

Bison dentary up-close.

Bison dentary up-close.

Once discovered, each fossil needed to be tagged with information about which animal it came from, where in the cave it was found, and what kind of sediment it was found in. We then bagged the specimens and bulk sediments to be screen-washed for microfossils and hauled them back to the surface in a bucket on a rope. In that sense, we were lucky we didn’t find anything bigger than the bucket. Once the excavations were complete, the site was remediated to protect exposed sediments from further weathering and to leave the site in a pristine state for future paleontologists.

screen washing

Eric Holt with a set of drying screen-wash screens.

Now that the final and most recent field season has ended, Natural Trap Cave is closed again for the foreseeable future. Susumu is going through identifications and Jenny is analyzing microfossils from the site. This study will provide a greater understanding of how life was changing in a warming world at the end of the last ice age, with implications for how life might respond to current and projected warming. Eric and I are very thankful to have been volunteers involved with this project and are looking forward to some great results.

Banosky Lab at NTC

Barnosky lab members outside of Natural Trap Cave. From left to right: Nick Spano, Jenny McGuire, Eric Holt, and Susumu Tomiya.

Support UCMP's See-Through Dinosaur Skull Project

Crowdfunding for See-Through Dinosaur Skull

Baby Triceratops skull next to a 3D printed subadult Triceratops rostral bone or "beak".

Through a crowdfunding initiative with UC Berkeley, the UCMP would like your support in creating the first ever "see-through" dinosaur skull!

UCMP is a leader in paleontological research and with your support of this project, museum paleontologists will further explore how dinosaur skulls grow and develop as they change size and shape.

With this crowdfunding project, UCMP hopes to raise enough funds to CT scan, volume render and 3D print the first ever see-through dinosaur skull, starting with our baby Triceratops, the smallest and youngest Triceratops skull ever found.

After CT scanning the bones, medical imaging software renders the internal vascular network and cranial sutures visible inside the bones. This kind of analysis will potentially help UCMP paleontologists better understand how our small baby Triceratops, the size of a dinner plate, expands to food-truck size of nearly 9-feet long as an adult! Once the CT scans of the bones are completed, we will 3D print and assemble the individual printed "bones" into a see-through baby Triceratops skull. This new skull will join our Triceratops growth series exhibit in the entrance of the Marian Koshland Bioscience Library, Valley Life Sciences Building, one floor above the UC Museum of Paleontology.


Triceratops Growth Series exhibit in the Marian Koshland Biosciences Library, Valley Life Sciences Building, UC Berkeley.

Please consider donating! Visit our crowdfunding page,, where you will find more information about this research, more awesome photos of the Triceratops skull and 3D printed see-through casts.

Of course, with your donation comes perks: a Thank You Shout Out in our UCMP newsletter, Digital Poster of our Triceratops, special behind-the-scenes tours of UCMP and Sather Tower, an up-close look at the original baby Triceratops skull - plus a unique opportunity to join UCMP paleontologists on a dinosaur dig in Montana!

Again, thank you for your support and check back for project updates!

UCMP's Lisa White highlights the geology of California in NOVA series

At a Sierra foothills gold mine, White poses with Kirk Johnson, director of the Smithsonian National Museum of Natural History and narrator of “Making North America.” (Photo courtesy of Lisa White)

At a Sierra foothills gold mine, White poses with Kirk Johnson, director of the Smithsonian National Museum of Natural History and narrator of “Making North America.” (Photo courtesy of Lisa White)

Making North America, a 3-part NOVA series that originally aired on PBS in November 2015, is a richly illustrated journey through the geological history of the North American continent. UCMP Director of Education and Outreach Lisa White appears in episodes one (Origins) and three (Human) in segments shot in northern California.

Lisa joins paleontologist and Director of the Smithsonian National Museum of Natural History Kirk Johnson, the series host and narrator, along the San Andreas fault in Tomales Bay and in a gold mine near Placerville, CA to explain the unique geological features in California.

Lisa was recently profiled in Berkeley News and talked about her experience filming the series and her commitment to broadening participation in the geosciences.

New fossil footprint exhibit debuts online

Fossil tracks logoVisit the new UCMP/University of Colorado online exhibit on fossil tracks! It is fascinating to consider that fossil footprints and trackways offer direct physical evidence that ancient animals passed through an area long ago. However, these trace fossils also provide important clues that shed light on several aspects of paleobiology, such as anatomy, locomotion patterns, behavior, and footprint preservation. The website provides basic information about the preservation of fossil tracks, how they are studied, and where they have been found. You can also test your fossil track expertise in the “Who made these fossil tracks?” section.

University of Colorado graduate student, Allison Vitkus is lead author on the exhibit, which was produced with funding from a National Science Foundation grant to Karen Chin and Martin Lockley. Martin Lockley spent his career at the University of Colorado Denver amassing one of the world’s most diverse collections of fossil tracks. This extensively-studied collection was held at the University of Colorado Dinosaur Tracks Museum in Denver but has now been moved to the University of Colorado Museum of Natural History in Boulder. NSF provided funds to transfer the specimens, make curatorial improvements to the collection, develop a searchable online catalog of the collection, and share information about this exciting collection with the public in this new UCMP online exhibit!

Global change consensus statement having a global impact

Page from consensus statementOver a year ago in a May 30, 2013, blog post, we reported on Professor of Integrative Biology and UCMP curator Tony Barnosky’s presentation to Governor Jerry Brown of a statement about global environmental problems and what people must do to ensure the health of the planet. That statement was written at Brown’s request after the Governor had heard about a Nature paper that Barnosky had coauthored with his wife, Stanford professor of Biology and UCMP research associate Elizabeth Hadly, and several other scientists in June 2012 (Nature 486:52-58). Brown wanted to use the statement as a powerful tool with which to help him shape environmental policy, and it has done that. Furthermore, the statement which has now been endorsed by over 3,300 people (mostly researchers) around the world, has influenced environmental policy well beyond California’s borders. Read the complete statement on the ConsensusForAction website.

Governor Brown presented copies of the statement to President Obama and Chinese President Xi Jinping. Since then, California and China have agreed to jointly develop green technologies and to reduce greenhouse gases. California, Oregon, Washington, and British Columbia have signed a pact to use ideas set forth in the statement as the basis for making energy and environmental decisions. The statement has been translated into several other languages and has found its way into the hands of politicians around the globe. Members of Nepal’s parliament have signed the statement and intend to address climate change when writing a draft for their new constitution. As Hadly put it, “We never could have guessed the reach this paper has had.”

In the July 24, 2014, issue of Nature (Nature 511:402-404), a news feature praises the work of “information advocates” Barnosky and Hadly.

Pollen may help solve the mystery of why a pre-Columbian city in Mexico was abandoned

My research focuses on the Holocene geological time period, the last 10,000 years of Earth history. An accurate picture of past climate can help us understand the relationship between past environmental change and ancient societies. In this post, I describe how my summer fieldwork and my broader dissertation project link summer rainfall, microscopic grains of pollen, and an ancient city in Mexico.

The pre-Columbian city of Cantona is an impressive sight, even today. Located near the border of the Mexican states of Puebla and Veracruz, in the Oriental Basin, it covers 12.6 km2 and features a complex network of streets, ball courts, and pyramids. At its peak, between 1,750 and 1,000 calendar years before present, the site was an important Mesoamerican center of trade in obsidian. Archaeological investigations suggest that the city was abandoned abruptly at approximately 1,000 years ago. While the cause is unknown, many have invoked climate change as a possible contributing factor, partially because of the lack of surface water in the region today. This, however, requires an accurate picture of climate change at least 900 years before we had reliable, instrumental measurements of temperature and rainfall.

Cantona ball court

A ball court at the pre-Columbian city of Cantona. Photo by Tripti Bhattacharya.

All is not lost, however. It turns out that past climates leave microscopic traces in lake sediments. A wet climate, for instance, will leave behind different clay minerals than a dry climate. The pollen preserved in lake sediments can also tell us about the regional vegetation at the time the sediments were deposited, which in turn reflects regional climate. Various techniques like radiocarbon dating can be used to establish the age of the sediments. Detailed analysis of pollen composition or sediment geochemistry can therefore provide a long-term perspective on climate change. My research focuses on lake sediments from a volcanic crater lake called Aljojuca that is approximately 30 km south of Cantona. In 2007, a team from the GFZ German Research Centre for Geosciences and Mexico’s Universidad Nacional Autónoma de México took a 12 m sediment core from the lake. Radiocarbon dating suggests that this core contains a continuous, 6,000-year sediment record.

This summer, I collected pollen samples from contemporary vegetation to improve our interpretation of our pollen results from the Aljojuca core. Understanding how vegetation changes along natural gradients of temperature and precipitation (for instance, up the slope of a mountain) can help us interpret the results we see in fossil pollen assemblages. We can even characterize the composition of the pollen created by local vegetation by analyzing the modern pollen preserved in surface soils, small ponds, or even cushions (called polsters) of moss!

Understanding Science in the video spotlight

The California Academy of Sciences produced a video that uses UCMP's Understanding Science website's How Science Works flowchart to map the discovery of a new spider family. UCMP Education and Public Programs team leaders Judy Scotchmoor and Lisa White have starring roles! Watch the video at Science360.

A salute to the Engdahl family

The Engdahl family

From left, Robert, Jane, Duane, and Cathy (Bras) Engdahl. Photo courtesy of Bill Clemens.

The Morris Skinner Award is the Society of Vertebrate Paleontology’s way of honoring those who have added to our knowledge through their contributions to collection of scientifically significant fossils. At its annual meeting in Raleigh, North Carolina, the society honored the Engdahl family of Garfield County, Montana, for their long-term, multi-generational support of paleontological research and education. Students, staff, and faculty associated with UCMP have benefited greatly from the Engdahls’ help and hospitality.

In the late 1960s, the late Harley Garbani went to the valley of Hell Creek in northeastern Montana with the goal of collecting skeletons of dinosaurs for exhibit at the Natural History Museum of Los Angeles County. He was particularly successful in his discoveries on the Engdahl Ranch. In addition to two skeletons of Tyrannosaurus rex he discovered the remains of other non-avian dinosaurs, which were collected with the help of Lester Engdahl and his sons, Robert and Larry.

On the Engdahl Ranch, Harley also discovered concentrations of fossils of mammals, lizards, turtles, and other relatively small vertebrates that lived with the dinosaurs. In 1972, Harley, who became a field research associate of UCMP, introduced Bill Clemens and students from our museum to the Engdahls and these rich concentrations of small fossils. This was the beginning of a continuing project to study the evolution of the fauna and flora that lived with the last of the dinosaurs and the survivors of the mass extinction at the end of the Cretaceous. UCMP’s collections now contain extensive samples of fossil plants and animals from this interval of earth history. These continue to be the bases for a wide variety of research projects.

Through the years until his death in 1995 Lester Engdahl supported UCMP field parties. For example, he helped us refurbish a homesteader’s cabin and made it available to our field crews. In the summers the cabin provided a kitchen and shelter from the more than occasional thunderstorms. The rest of the year it served as a secure storage place for field supplies. Lester’s son, Robert Engdahl, his wife Jane, and their children, Duane and Cathy, were particularly supportive and helpful. Jane and her children “caught the bug” and became skilled in prospecting for vertebrate fossils. Many summer field seasons opened with expeditions to collect fossils or evaluate sites that they had discovered.

Field work in Garfield County continues to be more than just collecting old bones, shells, and leaves. Since 1972 over fifty undergraduate and graduate students from Berkeley and other universities have come to Garfield County in the summer to learn collecting and research techniques. Nine of these students from UCMP completed research for their Ph.D. degrees making use of information on the geology and fossils collected in the area. This involvement continues as the Engdahls support the work of field parties from the University of Washington and the Burke Museum led by UCMP alumnus Greg Wilson.

Jane Engdahl and Cathy Engdahl Bras attended the meeting in Raleigh and received the Skinner Award. We add our thanks for all they and their family have contributed to the success of UCMP’s programs of research and education.

Archosaurs: A new online exhibit

UCMP is proud to announce the completion of its web exhibit on archosaurs — I guess you could call it a Diapsida exhibit but we've chosen to focus on the archosaur lineage.

Matt examines the skull of Tomistoma

Matt Wedel examines the skull of Tomistoma, the False Gharial. Photo by Vanessa Graff.

It's roots go back to the end of the spring semester, 2006. Former UCMP grad student John Hutchinson (Ph.D., 2001, now a Professor of Evolutionary Biomechanics at the University of London's Royal Veterinary College) had updated a number of the museum's web pages on dinosaurs, and he was asked whom he'd recommend for writing new material on the archosaur lineage. John suggested that we approach grad student Matt Wedel in the Padian Lab, and that summer the research, reading, and writing began.

Matt sent the bulk of the content for the archosaurs exhibit to me in May of 2007, but that was also the year Matt earned his Ph.D. and got a new job. Between the job and family, it was tough finding time to work on the final bits of archosaurs.

Meanwhile, I tracked down images, formatted the text that I had for the web, and continued to check in with Matt periodically. In May of 2010 Matt sent me the final pieces of archosaurs, the most important being his text on modern crocodilians. For the next several months, I worked with Matt to resolve some issues surrounding the archosaur phylogeny and I continued to hunt down images. By November, the exhibit was finally ready … except navigating among the numerous pages within the exhibit was quite difficult, so we decided to postpone its launch until UCMP Webmaster, Josh Frankel, could implement a solution. With the navigation issue resolved, archosaurs is now up and ready for the public. It only took us about six years!

The museum appreciates not only Matt's expertise, but his dedication — he was determined to complete the archosaurs exhibit no matter how long it took. And now it's finally “done” … although as Matt will be the first to tell you, the perceived relationships between organisms — particularly extinct ones — are always in a state of flux (due to new evidence and interpretations). So maybe Matt isn't completely done with archosaurs after all ….

Matt Wedel is currently Assistant Professor of Anatomy at the Western University of Health Sciences in Pomona, California.

Lessons for today in ancient mass extinctions

This month's Evo in the News on Understanding Evolution looks at the work of incoming UCMP faculty curator Seth Finnegan. Seth is the lead author on a paper published in Proceedings of the National Academy of Sciences showing that the end of the Ordovician marked a true mass extinction caused by habitat loss due to falling sea levels and cooling of the tropical oceans. The Evo in the News feature explains and discusses the significance of this research, and includes additional links, resources, and questions for use in classrooms.

Read Evo in the News: Lessons for today in ancient mass extinctions.