At the first clap of thunder in late spring, Wyoming’s fossil hunters dust off sturdy boots, wide-brimmed hats, rock hammers, and brushes. For paleontologist Jean-Pierre Cavigelli, it’s also time for another annual ritual: trimming back his shaggy winter beard into a warm-weather “cowboy mustache.” Thunderstorms in the high plains of central Wyoming, where the 64 year old leads public dinosaur digs for the Tate Geological Museum at Casper College, peak in early summer; those storms wash away surface dust, exposing bands of badlands, and eroding outcrops and gullies to reveal ancient fossils dating from the Late Jurassic era, when stegosauruses roamed the land, to the end of the Cretaceous, when tyrannosaurus rex ruled.
Each summer, the museum runs a series of public Tate Dinosaur Digs, six-night expeditions to fossil sites across eastern Wyoming: a Morrison Formation quarry known for Jurassic-era stegosaurus and allosaurus material, perhaps, or a Lance Formation bone bed, a layer of late-Cretaceous rock where triceratops fossils are common. Travelers can spend dig-days kneeling in the dirt with small tools, searching for teeth, bones, shells, and other fragments of a long-lost time. And the trips, which start at $1,350 per person and include meals, lodging, and transport, are no mere play-acting exercise—they contribute directly to the museum’s work: Any specimens found will go back to the Tate for further cleaning, study, and possibly display.
“You just have to be able to get down on the ground and get back up again—that’s kind of the minimum requirement for these trips,” says Cavigelli, who has been with the museum since 2004. The expeditions, capped at eight guests, draw a wide mix of travelers ages 16 and up, from teens flirting with futures to retirees circling back to an old interest. “I often hear, ‘When I was young, I wanted to be a paleontologist, but I decided to make money instead.’”
Cavigelli takes the dig, so to speak, in stride. A biology graduate of the University of Chicago who formerly worked as a ski instructor and rafting guide, he got hooked on fossils after finding remains of ancient mammals and turtles in the South Dakota Badlands. He has now spent roughly 35 years in paleontology—even if it hasn’t overflowed his coffers. This path has taken the Boston native from early field jobs at the University of Wyoming and the National Park Service to professional expeditions in Niger, Tanzania, and Mongolia, eventually bringing him back to Wyoming to run an independent prep lab (where fossils are cleaned and prepared for study) and private pay-to-digs before joining the Tate.
To manage any Jurassic Park–level expectations, Cavigelli likes to be a voice of reason for his groups of citizen scientists, a growing cohort of travelers interested in hands-on research experiences. “People always ask, ‘Will I find a claw? Will I find a tooth?’” he says. “And the answer is, ‘You might, but you also might get struck by lightning. Or get hit by a car. Or win the lottery.’” Most days in paleontology are patient ones. What’s the rush when you’ve got the 4.5-billion-year sweep of Earth’s history—what scientists call “deep time”—on your side?
High bone density
Wyoming has been a known fossil hot spotfor 150 years or more, thanks to an ideal combination of geological history and present-day weather conditions.
Photo by Candids with Cait
Wyoming, once a prehistoric network of rivers and coastal lowlands beside an inland sea, is one of the most fossil-rich states in the country—ranking second (after California) in recorded finds according to the Paleobiology Database, which aggregates fossil records from research institutions worldwide. But what draws enthusiasts and professionals like Cavigelli to Wyoming isn’t just the sheer number of bones but also the perspective that paleontology provides: zooming out to capture a climate in constant flux, continents steadily on the move, and extinction and emergence in the plant and animal kingdoms over what feels like an eternity. “We’re talking millions upon millions of years’ worth of shifts,” Cavigelli says. “That’s time we can’t even fathom. We only get to experience a tiny bit.”
Once buried in sediment, the bones hidden in this part of the country were later exposed by the rise of the Rockies and steady erosion in Wyoming’s dry, sparsely vegetated landscape—making fossils not just numerous but unusually accessible as well. Your chances of finding a T. rex during a dig, while minuscule, are better in Wyoming than almost anywhere else.
Cavigelli learned that firsthand back in 2005, when he stumbled upon what he calls his “legacy find”—a specimen christened “Lee Rex” after the owner of the ranch where it was discovered—during a bathroom break on a Tate pay-to-dig trip. For five years, he left the bones in the ground so he could use them as a teaching tool for his tour groups: “This is what you want to look for, folks,” he would say. But in 2010, Cavigelli returned with roughly 20 volunteers who worked for about five weeks to excavate Lee Rex’s remains: 23 vertebrae, a pelvis, one leg bone, one intact side of a rib cage and the jumbled heap of the other, and the Y- and V-shaped chevron bones beneath the tail. “We made a big hole looking for the rest of it,” Cavigelli remembers. “I suspect that it disappeared in a flood 67 million years ago.” In the course of deep time, such losses are to be expected.
All specimens uncovered on the Tate Geological Museum’s public dig trips are transported back to the lab for further study.
Courtesy of Casper College
The crew encased the fossil-bearing block of hardened sediment in “jackets”—burlap strips dipped in plaster used to stabilize skeletons like this—before transporting the 18-foot-long, 8-foot-wide specimen to Casper. Lee is too big and too heavy to fit inside the museum, so he’s housed in a private outbuilding reinforced with a concrete floor and outfitted with an extra-wide garage door simply to get him inside. It’s hard to believe this formidable creature’s likely gait—new research suggests—was closer to poultry than predator.
Lee Rex is one in a long line of formative fossils in Cavigelli’s life. He has also helped unearth a Cretaceous crocodile “the size of a flattened soccer ball” in Tanzania, its black backbone visible in a cliff face. On a private outing, he discovered a 15-million-year-old fossil bird—“the only bird of that age from Wyoming,” he claims—which he later donated to the Tate. He also worked on a plesiosaur that came complete with devoured prey: “little baby ichthyosaur vertebrae” preserved in its stomach, along with some gravelly gastroliths. “The plesiosaur would eat stones to help with digestion,” he explains. “So that was cool to see.”
Despite the many memorable times in the field, Cavigelli explains that he honed his real paleontological craft in a garage prep lab he ran out of his Laramie home. Countless hours of scraping, chipping, and chiseling with dental tools, air scribes (pen-size pneumatic chisels), and tabletop sandblasters allowed him to liberate specimens from stone. Even as equipment and crews have grown more specialized, and the digs more complex, his work has always returned to that same patient labor—“where nine-tenths of paleontology happens,” he says.
But it’s the remaining tenth—the part that Tate director Dalene Hodnett fondly refers to as “playing in the dirt”—that tends to get the most attention. Last year, Cavigelli, helped along by a team of volunteers and students, made local headlines for helping excavate another major specimen: a sauropod discovered near Alcova Reservoir nicknamed “Woody,” after the person who found him.
Playing in the dirt
Cavigelli’s biggest find, nicknamed “Lee Rex,” is potentially the first T. Rex to stay in Wyoming permanently after excavation.
Photo by Candids with Cait
The chance of such a discovery is what draws people to the Tate’s dinosaur digs. And they’re not alone in their curiosity: As of May 2020, roughly one in four adults in the United States reported having participated in a citizen-science activity, according to a Pew Research Center survey.
“Our citizen scientists may not be entering data, but they are certainly contributing to it,” says Cavigelli. Tate digs take place mostly on private ranches, so any unearthed fossils would, in theory, belong to the landowner. But in practice, he says, “I make deals with them to donate to my cause.” Once excavated, the finds are collected and processed in the Tate’s prep lab, where more volunteers—Casper College students and local retirees, mostly—trade Wyoming’s sunstruck horizons for fluorescent light, freeing bone from the surrounding rock (or “matrix”); it can take months or even years before a specimen is ready for study or display.
Last year, lab volunteers donated a combined 6,700 hours of work on projects like prepping Woody the sauropod for its museum debut or piecing together what looks to be a nearly complete triceratops skull from a 2005 excavation, including two horns, part of a neck frill, and the nose-piece—the latter only recently identified within its plaster jacket.
Meanwhile, the Tate is expanding its role in Wyoming’s fossil landscape. The museum serves as an official repository for fossils excavated on terrain overseen by the Bureau of Land Management (BLM)—an uncommon distinction for a public two-year college. “There are very few junior colleges that would dedicate the resources to this endeavor,” says Hodnett, the director, who describes the partnership as “something of a unicorn.”
Cavigelli says he’s eager to deepen the Tate’s collection so that “by the time I retire in five years, there’ll be plenty of stuff to keep the next paleontologist occupied,” he explains. He imagines a leisurely life of fossil-hunting and birding while his successor, and ideally visiting scholars, continue raising the Tate’s profile among academics and travelers alike. Hodnett says the museum is working toward photogrammetry, acquiring the equipment needed to create digital 3D models of complete specimens, bones, and fragments that researchers around the world can view from afar.
Work by institutions like the Tate is perhaps more important than ever as fossils increasingly fetch record sums from private buyers. A tyrannosaurus rex discovered near Buffalo, South Dakota, now resides at the Natural History Museum Abu Dhabi, which acquired “Stan” for $31.8 million at a Christie’s auction in 2020. And in July 2024, Sotheby’s sold a nearly complete stegosaurus skeleton discovered in Moffat County, Colorado, for a record $44.6 million to hedge-fund billionaire Ken Griffin, who has said he plans to loan “Apex” to a public institution.
Dinos like Lee Rex aren’t the only prehistoric creatures on display at the Tate—take Dee, an Ice Age mammoth discovered while building an oil well.
Courtesy of Visit Casper (L); photo by Candids with Cait (R)
The result, Cavigelli says, is that public institutions are increasingly priced out of acquisition. “We just can’t pay that kind of money,” he says. Even when fossils end up in museums, record auction prices can send them far from where they were found—separating them from the institutions that would benefit the most from studying them.
But across the West, there’s a growing push to keep excavated dinosaur bones close to home: on display in regional museums for visitors to see, supporting local economies instead of disappearing into private collections or overseas institutions. Cavigelli sees his work as part of that effort but acknowledges that auction headlines, coupled with the success of Jurassic World Rebirth (the sixth highest-grossing film of 2025 worldwide), also help drive citizen-science tourists to his part of the planet. Suddenly, he says, “Everybody wanted to come dig dinosaurs with us”—the Tate’s 2026 expeditions sold out in less than 24 hours. In more than 20 years of leading the program, Cavigelli had never seen the trips fill up so quickly.
That rising curiosity hasn’t gone unnoticed by Wyoming’s travel industry. Dominic Bravo, executive director of the Wyoming Office of Tourism, says the state increasingly sees its fossil wealth as a way to create “high-value experiences” that draw travelers from outside the region. But for Cavigelli, those once-in-a-lifetime adventures amount to a very real daily grind: the chisel and scrape of rock from bone, time sifting down to dust.
Other opportunities to dig deeper
Dates for Cavigelli’s 2027 dinosaur digs will be announced this winter on the Tate website. And for travelers who couldn’t snag a spot for this year, Wyoming offers other illuminating paths to dino discovery. Near Kemmerer, private quarries in Fossil Basin let visitors dig for Green River fish fossils, while nearby Fossil Butte National Monument preserves the same 52-million-year-old lake beds in place—their finely detailed fish, plants, and insects visible but protected from collecting. At Red Gulch Dinosaur Tracksite, a short walk across BLM land leads to 167-million-year-old tridactyl (three-toed) footprints pressed into stone. And in Thermopolis, the Wyoming Dinosaur Center’s “Dig for a Day” program places visitors at active field sites, where they can excavate alongside staff paleontologists, learning proper field techniques and documenting finds.
