In his long career as a paleontologist, J.P. Cavigelli has worked in Niger, Tanzania, Mongolia, Alaska and the Dakotas. But for all his adventures, the Casper resident has yet to find a better place to hunt dinosaur bones than Wyoming.

In simple terms, this is because most of the mountain ranges in Wyoming formed near the end of the dinosaur age, he explained. As they rose, they shed the upper layers into the basin lands and exposed older rocks along the mountain edges.

That, combined with Wyoming’s relative lack of vegetation, makes fossil-bearing rocks readily visible. All you have to do is look, he said.

Once, while leading a pay-to-dig field trip on a ranch in eastern Wyoming, Cavigelli took a short hike to “get rid of some coffee,” in private. While relieving himself, he said, he happened to notice an interesting looking fossil. It turned out to be one piece of an unusually well-articulated Tyrannosaurus rex. Dubbed “Lee Rex,” it’s the finest unearthed T. rex specimen that remains in Wyoming, he said.

Wyoming paleontologist J.P. Cavigelli takes notes while on a fossil field trip in Wyoming. (Steve Pfaff)

“At least that’s the story my friends like to tell, and I’m sticking to it,” Cavigelli said, pointing to a framed photo on his office wall of himself reenacting the moment of discovery.

Quick with light sarcasm, heavy wit and an infectious laugh, Cavigelli speaks and looks the part of a rugged yet cheerful outdoor adventurer. One of the perks of being a paleontologist in Wyoming is spending most summer days trekking across the prairie, turning over rocks, digging holes and carefully sweeping dirt off old bones. The rest of the year, he can be found in the lab at the Tate Geological Museum on the Casper College campus.

Cavigelli, 61, serves as the museum’s prep-lab manager, field operations specialist and collections manager. In the lab, Cavigelli and a crew of volunteers — mostly retirees — spend countless hours meticulously chipping and dusting to expose fossils — both large and tiny — from the sediment and rocks that preserved them. Each specimen is identified and cataloged into a computer database. Sometimes bones are reassembled for display. Although the Tate isn’t a research facility, it frequently welcomes researchers from all over the world to examine what Wyoming’s fossils might reveal about the past.

Paleontologist J.P. Cavigelli examines a cast containing the bones of “Lee Rex” at the Tate Geological Museum Feb. 28, 2023. The Tyrannosaurus rex fossils were discovered on a ranch near Lusk. (Dustin Bleizeffer/WyoFile)

There are plenty of fossils at the Tate to examine, ranging from the Cambrian, which left tiny sea creatures like trilobites found in Wind River Canyon, to the Pleistocene, which deposited the remains of mammals both big and small, such as the 11,000-year-old mammoth and harvest mouse found in Converse County.

Cavigelli’s main area of interest? All the critters he can find, he said with a laugh. But what he especially enjoys about paleontology is the quiet, meditative work of “prepping” fossils in the lab.

“Mostly, I want to add to our collection here,” he said. “Recently we’ve been working the Morris Formation [from the Jurassic] down by Medicine Bow — so the Como Bluff area, which is pretty famous in the dinosaur world. We’re looking at Cretaceous dinosaurs on a ranch in eastern Wyoming, and last summer we started doing some work in southwestern Wyoming on Eocene fossils, so 50 million years old, 15 million years after the dinosaurs went extinct.”

Fun in the field

In addition to his paleontological expertise, Cavigelli is particularly well suited to lead field research and the museum’s pay-to-dig program, according to Tate Museum Director Dalene Hodnett. “He’s just fun to be around,” she said. “So not only are they on a trip of a lifetime getting to [dig for fossils], they’re also having a great time and enjoying each others’ company.”

Paleontologist J.P. Cavigelli holds a Hadrosaur jaw at the Tate Geological Museum in Casper Feb. 28, 2023. (Dustin Bleizeffer/WyoFile)

He’s also resourceful, Cavigelli’s longtime paleontology buddy Anton Wroblewski said.

He recalls the time Cavigelli found a wide-brimmed cowboy-like hat at a thrift store. Wroblewski said it looked more like it was retrieved from a dumpster but concedes his friend’s story. Cavigelli washed the hat, which lost its shape, and it became a fixture of his fieldwork attire. While settling in for chips-and-salsa in the field one day, Cavigelli realized they had no bowl for the salsa, so he dumped it in his cherished hat and passed it around.

“I’m like, ‘You gotta be kidding?’ And he’s just like, ‘What’s wrong?” while sporting a grin, Wroblewski recalled. The group was amused by the make-shift bowl, but politely declined a dip. “He’s a very resourceful guy.”

Cavigelli continued to wear the “salsa hat” for many years after.

A T-shirt designed by Anton Wroblewski depicts his friend, paleontologist J.P. Cavigelli (bottom left). (Anton Wroblewski)

On another dinosaur dig, Cavigelli used all the gasoline from his SUV as camp stove fuel, according to Wroblewski. When it came time to drive home, Cavigelli set out to a nearby RV camp full of retirees to ask for some gasoline with only an empty bean can to fill up. He came back with a borrowed gas can, demonstrating his faith in the kindness of strangers — and his infectious charisma.

“It was a classic J.P. moment,” Wroblewski said. “It worked.”

Finding his way to Wyo fossils 

Cavigelli’s curiosity for all animals, both living and extinct, began as a child in Massachusetts. He became a birdwatcher at age 10 — a pursuit he still enjoys today, albeit a bit passively by “birding” standards, he said. 

His interest in paleontology sparked while taking a break from college. He’d joined a friend who was surveying prairie dogs at Wind Cave National Park in South Dakota. While on a side-trip to Badlands National Park, he found a fossilized skull of an oreodont, a sheep-like mammal, “and I’ve been hooked ever since,” he said.

While attending the University of Chicago in the early 1980s, Cavigelli spent a summer in Wyoming doing field work for University of Wyoming paleontologist Jay Lillegraven. 

Boxes of rocks containing fossils await “prepping” at the Tate Geological Museum Feb. 28, 2023. (Dustin Bleizeffer/WyoFile)

He took a long break as a ski bum and worked as a whitewater guide in Colorado and Australia before settling in Wyoming in 1990. Before arriving at the Tate in 2004, he’d spent many years conducting field work, and did a two-year stint as collections manager for the University of Wyoming’s Department of Geology and Geophysics.

Cavigelli married a few years ago and recently “retired” from playing hockey on the local ice — to save his own bones.

In addition to adding to the Tate’s collection, Cavigelli said he’s looking forward to getting back in the field this summer with colleagues and clients.

“It’s lots of fun,” he said. “And it’s really easy to sell a dinosaur hunting trip, because people love dinosaurs.”

WyoProfiles examine the remarkable, notable and fascinating lives of state residents — both living and gone. If you have an idea for an individual you would like us to profile, email

Dustin Bleizeffer is a Report for America Corps member covering energy and climate at WyoFile. He has worked as a coal miner, an oilfield mechanic, and for 25 years as a statewide reporter and editor primarily...

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  1. Great story / profile of a fun person. I sure enjoyed reading this. Lots of interesting characters in Wyoming.
    Good job of capturing the soul of the story.