Strike a pose: Yale’s iconic dinosaur skeletons get a new look

While the Yale Peabody Museum undergoes a historic renovation, many of its prized dinosaur skeletons are being refurbished — and reposed — in Canada.

Brian Ross is a blacksmith, but not the kind that shoes horses. Ross rebuilds dinosaurs.

He is the head of fossil mounting at Research Casting International (RCI), an Ontario-based company that specializes in preparing and preserving mounted fossil displays.

His latest project is massive in size and historical importance — and of particular interest to the Yale community. The world’s first Brontosaurus specimen, the skeletal hulk that has towered over visitors to the Yale Peabody Museum for nearly a century, requires assembly.

For the past couple of years, RCI’s team of fabricators and conservators has been refurbishing and reposing several of the Peabody’s historic fossil skeletons, including Brontosaurus, as the museum’s building undergoes a transformative renovation.

When the iconic Yale museum reopens in 2024, the skeletons will return in more dynamic and scientifically accurate poses — thanks in part to the work of RCI’s expert technicians and the Peabody’s staff.

A person working on a dinosaur skeleton.
Aligning the ribs is one of the more challenging aspects of rebuilding a Brontosaurus. (All photos by Dan Renzetti)

The fossil mounts’ new poses will reflect the new scientific consensus that dinosaurs were alert and lively animals, not the plodding, tail-dragging brutes depicted in old textbooks and popular culture over the past century. Once the renovation is completed, the exhibits in the museum’s Burke Hall of Dinosaurs will highlight the prominent role Yale scientists past and present have played in illuminating the history of life on Earth, including the evolution of dinosaurs.

The Peabody’s fossil exhibits include the holotype specimens — the first examples of their kind discovered anywhere — of several genera, including Brontosaurus, Triceratops, and Stegosaurus, as well as some of the earliest museum mounts of dinosaur skeletons.

It’s definitely one of the larger and most historically significant projects that our organization has taken on,” said Ross, standing behind an anvil at his workspace in the blacksmith shop at the company’s 48,000-square-foot headquarters in Trenton, Ontario, this summer. “The Brontosaurus alone is such a world-renowned dinosaur.”

In January 2020, RCI staff visited the Peabody, disassembled the dinosaur and mammal fossil mounts, carefully labeled and packed up the bones, and transported them to the company’s facility — a sprawling warehouse located on the Bay of Quinte on the northern shore of Lake Ontario — where the assembly continues.

Each of the fossils receive a thorough cleaning and repair in RCI’s preparation and conservation lab before they’re moved on to the blacksmith shop.

In front of Ross, one of the Brontosaurus’ tail vertebra rests on a sandbox. It will be encased in a protective steel armature before it’s welded onto the skeleton, which is being rebuilt on a steel-pipe frame that spans the spacious room. The sauropod’s ribcage, hind legs, and dorsal bones — or spine — are mounted, and the blacksmiths have begun rebuilding its tail. (Sauropods are a group of gigantic quadruped dinosaurs, including Brontosaurus, that had long necks, small heads, and trunk-like legs.)

A person working on a dinosaur skeleton.
Sparks often fly in RCI’s blacksmith shop.

Angle grinders whir and shower sparks as the blacksmiths form-fit half-round steel bands onto fossilized bones. Tail bones encased in their armatures are laid out on foam mats on the workshop floor. Other bones ready to be welded into place line shelves and wooden pallets along the workshop’s back wall.

The Peabody’s fossil mounts are treasures,” Ross said. “It takes a lot of time and patience to make sure we produce the best possible mount.”

Dinosaur nerds

Founded in 1987, RCI has built hundreds of fossil skeletons and other museum exhibits for institutions across North America, Europe, Asia, and Oceania. It refurbished the fossil mounts in the Smithsonian National Museum of Natural History while the institution’s dinosaur hall underwent a five-year renovation, which was completed in 2019.

The companies that do what we do probably can be counted on one hand,” said Peter May, RCI’s president and founder.

While the staff gives the Peabody’s specimens tender love and care, they are also in the process of assembling a blue whale skeleton for another institution on the facility’s main floor. Fabricators worked on the whale’s gigantic, bladelike jawbones. Not far away, a life-size and realistic-looking model of a Paraceratherium, a colossal hornless rhinoceros that, at about 44,000 pounds, was the largest mammal to ever walk the Earth, dwarfs the workers. (The company purchased the model for inclusion in a planned local natural history museum.)

May prizes the opportunity to work with the Peabody and its renowned specimens, particularly those excavated by Othniel Charles “O.C.” Marsh, the pioneering 19th-century Yale paleontologist whose expeditions in the American West yielded groundbreaking fossil discoveries, including the type specimens of BrontosaurusStegosaurus, Triceratops, and Pteranodon.

This is a treat for us dinosaur nerds,” he said. “These were the specimens that started paleontology.”

May marvels at how the Peabody’s preparators managed to assemble the original Brontosaurus mount in 1931 out of the bones Marsh had collected — beginning in 1879 — at Como Bluff, Wyoming.

They didn’t have much documentation to work from, and just had to piece the bones together as they went,” he said. “It’s amazing what they accomplished.”

May’s team has the benefit of nearly a century of science to work from since that original mounting. Over the past several decades, Yale scientists have conducted groundbreaking research on key evolutionary transitions between dinosaur, reptile, and avian species. Their work has helped track the evolutionary transition of dinosaurs into birds. The RCI’s fabricators have consulted closely with Peabody curators and other staff to ensure the skeletons’ new poses accurately reflect these and other breakthroughs.

A person cleaning a dinosaur fossil.
A conservator works on a long section of spine belonging to the Peabody’s American Mastodon.

We as an institution have entrusted RCI with our most precious specimens,” said Vanessa Rhue, the Peabody’s collection manager for vertebrate paleontology. “They, in return, are really taking this material to the next level, and presenting it to the world in such a way that it will be enjoyed and learned from for years to come.”

Each individual bone was surface-scanned and printed as a three-dimensional scale model, which the technicians use to visualize the new poses and reshape the skeletons, accordingly, May explained.

The model’s pose sets our path,” he said.

Changes to the 65-foot-long Brontosaurus will make the massive herbivore appear nimbler and more energetic. The tail, which previously rested on the ground, will be longer and raised in the air. Its neck also will be lengthened, and its head repositioned in a curious, birdlike manner.

It’s going to look a lot more dynamic,” Ross said.

Hip bones and dental picks

Four members of RCI’s team of fossil preparators toil quietly at workbenches cleaning and mending the bones of the Peabody’s American mastodon. One preparator works on a 5-foot-long section of the mastodon’s spine. Two others focus on its ribs. Another cleans the elephant-like skeleton’s hips. Another treats the bones of a sauropod belonging to the Cleveland Museum of Natural History.

Posters of dinosaurs — and one featuring hockey star Sydney Crosby — decorate the walls. The hip girdle of the Peabody’s Stegosaurus is set on a metal frame in the studio following a cleaning.

The preparators apply various organic solvents, including acetone, ethanol, and alcohol, to remove grime that had accumulated over the decades on the bones. They use dental picks and air scribes to remove plaster and other debris.

A warehouse.
The sprawling headquarters of Research Casting International, the Ontario-based company that is refurbishing and reposing the Peabody Museum’s beloved fossil mounts.

Preparator Amber Favreau scrapes plaster from a 5-inch crack in the mastodon’s hip. Once the plaster is cleared away, she will fill the crack with celluloid, which leeches less moisture than plaster, she explained. The mastodon is considered a “subfossil,” meaning it isn’t old enough — or sufficiently petrified — to have the organic material replaced by minerals.

After two days, Favreau had cleaned one of the ancient animal’s two hip bones, which now was much lighter in color than its opposite half. When finished cleaning, she’ll apply a layer of acrylic solution adhesive to the bones so that they remain stable. If needed in the future, the applied materials could be removed easily from the bones without damaging the specimen, she said.

The RCI team consults regularly with staff at the Peabody, sending monthly progress reports to New Haven and contacting the museum’s preparators with questions, said Amelia Madill, the company’s director of preparation.

For example, RCI is working on a Tylosaurus specimen — a predatory marine reptile the length of a school bus — that will be suspended from the ceiling of a new Central Gallery being built as part of the museum’s renovation. Madill conferred with the Peabody’s conservator on the type of adhesive to use on the fossil given that it will absorb a lot of direct sunlight in the new display.

We needed to find a different grade of adhesive with a high melting point,” Madill said.

Like many of her colleagues, Madill is excited for the opportunity to work on Brontosaurus.

When I think of dinosaurs, Brontosaurus is the first one that comes to mind,” she said.

RCI has mounted its fair share of massive sauropods. In 2016, the company completed a mount of a 122-foot-long titanosaur, one of the largest dinosaurs ever discovered, for the American Museum of Natural History in New York City. Brontosaurus, while not as tall or long as its Manhattan-based cousin, is a behemoth in its own right. It’s femur bones alone weigh upwards of 800 pounds.

I don’t think we’ve worked on anything as tank-like as the Brontosaurus,” she said. “It can require a lot of hands on deck just to position a bone.”

Work for posterity

The half-assembled skeleton in the blacksmith shop already bears indications of more dynamic motion. Its hind legs are bent as if the gigantic animal is walking. A caudal vertebra, or tail bone, is strapped into the hook block of a gantry crane. Ross mounts a scissor lift, which rises into place behind the skeleton’s hind legs. Garth Dallman, a display technician, operates the crane, lifting the bone into Ross’ grasp. Then Dallman dons a welding mask and climbs a ladder beside the scissor lift. He welds the bone into its steel bracket on the frame.

The brackets are bolted to the steel frame, meaning any individual bone can be removed easily, Ross explained.

You undo two bolts and a bone can come out while the rest of the specimen remains on display,” he said.

The most challenging part of assembling Brontosaurus is piecing together its ribs, Ross said.

There are so many axes and so much variation in the bones that it takes a lot of adjusting to get it right,” said Ross, who took up blacksmithing while in art school.

Two men working on a dinosaur skeleton.
Fabricators at RCI reassemble Brontosaurus, which will have a dynamic new pose when the Peabody reopens in 2024.

Once Brontosaurus is fully assembled, it will be taken apart again. The steelwork will be polished and painted. The bones will receive a follow up cleaning and then will return to the Peabody where the RCI team will reassemble them, just as they have been assembled in Ontario, on the museum floor.

After more than three years of work, it will be bittersweet to see the specimens leave, Ross said.

You get attached to them,” he said. “It’ll be the end of an era.”

For Madill, it’s exciting to consider all the people who will enjoy the fruits of RCI’s labors over the coming decades.

I just hope that 90 years from now, paleontologists and people in my field will look at our work and think, ‘They did a good job,’” she said.


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