Museums and the Triceratops Posture Problem – Part 2

Triceratops at the National Museum of Natural History.

Triceratops “Hatcher” at the National Museum of Natural History. Photo by the author.

Back in July, I wrote about how the forelimb posture of ceratopsian dinosaurs like Triceratops has puzzled paleontologists for more than a century. Most quadrupedal dinosaurs held their front legs straight under their bodies, and it would make sense if Triceratops and its kin did the same. However, when researchers attempted to physically articulate skeletons for museum displays, they found that that the humerus would only fit properly with the scapula if it projected horizontally from the torso – like the sprawling limbs of a lizard. Over the years, new specimens, new research methods, and new technologies have all been used to help resolve this conundrum, but a consensus has not yet been reached. Of particular interest to me is the unusually central role mounted skeletons in museums have played in this biomechanical mystery. The previous post covered the historic Triceratops mounts; this entry will take a look at some more recent Triceratops displays in American museums.

The Hatcher Project

In 1998, a visitor looking at the Triceratops mount at the National Museum of Natural History happened to sneeze. To her alarm, the sneeze was enough to knock a small fragment of bone off the pelvis and onto the floor. The visitor thoughtfully informed security, and after a thorough conservation assessment by Kathy Hawks, it was determined that the 93-year-old mount needed to come off exhibit, and soon. The delicate fossils had served valiantly through 23 presidential administrations, but now it was time for the skeleton to be disassembled and preserved for posterity.

Retiring the classic Triceratops gave Ralph Chapman, head of the Museum’s Applied Morphometrics Laboratory, an opportunity to take on a project he had been germinating for some time. Chapman wanted to demonstrate the potential of 3-D scanning technology for paleontology research by creating a high-resolution digital duplicate of a dinosaur skeleton. Today, the process of making and studying digital copies of fossils is both widespread  and remarkably straightforward, but in the late 1990s it was practically science fiction. Nevertheless, the historic Triceratops was an ideal digitization candidate for several reasons. First, the digital assets would reduce handling of the delicate and aging original fossils. Second, exact copies of the scanned bones could be made from milled foam and plastics to create a replacement exhibit mount. Finally, a digital Triceratops would be a great opportunity to revisit the ceratopsid posture problem in a new way.

digital hatcher

A rendering of the digital Hatcher. Source

The ensuing Hatcher Project (the Triceratops was named in honor of John Bell Hatcher, who found the original fossils in the late 19th century) was a collaboration between Museum staff and several industry experts, including Lisa Federici of Scansite 3-D Services and Arthur Andersen of Virtual Surfaces, Inc. The first step was to place stickers on 100 key points on the Triceratops. These points were recorded with a surface scanner, so that the historic mount could be digitally recreated in its original pose. After that, fossil preparators Steve Jabo and Pete Kroehler carefully dismantled the skeleton. Each bone from the skeleton’s right side* was then scanned individually, producing 20 gigabytes of data (you’re supposed to gasp…again, this was the late 90s).

*Bones from the right side were mirrored to reproduce the left half of the skeleton. 

Since the original mount had been a somewhat disproportionate composite, the team made a few changes when building the new digital Hatcher. Some elements, including the undersized skull, were enlarged to match the rest of the skeleton. In addition, parts that had either been sculpted or were not actually Triceratops bones – such as the dorsal vertebrae and the hindfeet – were replaced with casts acquired from other museums. The result was the world’s first complete digital dinosaur, and shortly afterward, the first full-sized replica skeleton generated from digital assets.

Updated "Hatcher" mount's rarely seen right side. Source

Hatcher’s seldom seen right side was briefly exposed recently, before the mount was moved to a temporary second floor location. Source

In April 2000, the Hatcher team convened at NMNH to determine how the new replica mount would be posed. Chapman, Jabo, and Kroehler were joined by Kent Stevens of the University of Oregon, Brenda Chinnery of Johns Hopkins University, and Rolf Johnson of the Milwaukee Public Museum (among others) to spend a day working with a 1/6th scale model produced by stereolithography specialist Jason Dickman. The miniature Hatcher allowed the researchers to physically test the skeleton’s range of motion without the difficulty of manipulating heavy fossils.

The day was full of surprises. The team was impressed by the wide range of motion afforded by the ball and socket joint connecting the Triceratops skull to the atlas. They also found that the elbow joints could lock, which may have been helpful for shock absorption when the animal smashed things with its face. Nevertheless, when it came time to articulate the humerus and scapula, the team essentially validated Charles Gilmore’s original conclusion that sprawling forelimbs worked best (although the new Hatcher mount stands a little straighter than the historic version, and a lot straighter than the New York Triceratops). While other paleontologists had used indirect evidence (like evenly spaced trackways and wide nasal cavities for sucking down lots of oxygen) to support the idea that Triceratops was a straight-legged, fast-moving rhino analogue, articulating the actual bones showed once again that ceratopsid forelimbs had to sprawl.

Houston and Los Angeles Mounts

LACM Triceratops mount. Photo by Heinrich Mallison, many more here.

LACM Triceratops mount. Photo by Heinrich Mallison, many more here.

Hatcher is the Triceratops I am best acquainted with, and I can’t help but think of it as the definitive example of this animal. However, two new Triceratops mounts demonstrate a radically different take on ceratopsid posture. In 2011, the Natural History Museum of Los Angeles County completed a thoroughly renovated dinosaur hall, which features a brand-new Triceratops mount at its entrance. Like Hatcher, this skeleton is a composite of several specimens, in this case excavated in Montana by LACM teams between 2002 and 2004. Phil Fraley Productions, the exhibit fabrication company behind Sue and the Carnegie Museum dinosaurs, was responsible for mounting the fossils. The primary specimen (LACM 141459, which provided the skull and right forelimb) is notable because it included a completely intact and articulated front leg. Although the analysis of this important find has yet to be published, exhibit curator Luis Chiappe tellingly chose an erect, rather than sprawling, forelimb posture.

Meanwhile, the Houston Museum of Nature and Science opened its colossal, 30,000 square foot Hall of Paleontology in 2012. Among the dozens of mounted skeletons on display is Lane, reportedly the most complete Triceratops ever found. The museum purchased the skeleton from the Black Hills Institute, and the company also constructed the display mount. Robert Bakker, who curates the Hall of Paleontology, specifically requested that Lane be given a straight-legged, trotting pose. With two legs off the ground, this display emanates strength and speed.

"Lane" at Houston Museum

“Lane” at Houston Museum of Nature and Science. Source

So how did the Los Angeles and Houston exhibit teams manage to construct plausible-looking, straight-legged Triceratops mounts? Since full descriptions of either specimen have not been published, it’s hard to say for sure. From the look of it, however, the new mounts both have narrower, flatter rib cages (as suggested by Paul and Christiansen), which allows more room for the elbow. Likewise, the shoulder girdles are lower than Hatcher’s, and they seem to have been rotated closer to the front of the chest. Also note that the forelimbs of the Los Angeles and Houston mounts are not completely erect – they are strongly flexed at the elbow, as is typical of many quadrupedal mammals.

These new mounts don’t mean the Triceratops posture problem is resolved, though. The angle of the ribs and the position of the scapula are apparently both touchy subjects, so alternate interpretations are sure to arise in the future. After all, Triceratops forelimb posture isn’t just an esoteric bit of anatomical trivia: it has major implications for the speed and athleticism of an extremely successful keystone herbivore. Understanding the limitations on this animal’s movement and behavior can contribute to our understanding of the ecosystem and environmental pressures in late Cretaceous North America. As such, I am eagerly awaiting the next round in this 100-plus year investigation.

A big thank you to Rebecca Hunt-Foster and Ralph Chapman for sharing their time and expertise while I was writing this post!


Chapman, R. Personal communication.

Chapman, R., Andersen, A., Breithaupt, B.H. and Matthews, N.A. 2012. Technology and the Study of Dinosaurs. The Complete Dinosaur, 2nd Edition. Bloomington, IN: Indiana University Press.

Fujiwara, S. and Hutchinson, J.R. 2012. Elbow Joint Adductor Movement Arm as an Indicator of Forelimb Posture in Extinct Quadrupedal Tetrapods. Proceedings of the Royal Society 279: 2561-2570.

Hunt-Foster, R. Personal communication.

Paul, G.S. and Christiansen, P. 2000. Forelimb Posture in Neoceratopsian Dinosaurs: Implications for Gait and Locomotion. Paleobiology 26:3:450-465.


Filed under anatomy, dinosaurs, fossil mounts, history of science, marginocephalians, museums, NMNH, reptiles

12 responses to “Museums and the Triceratops Posture Problem – Part 2

  1. Ralph Chapman

    It should be noted that somewhere in the process of this blog Cathy Forster was left out of the group that worked on this project and developed the posture – and she was a very, very important part.

    As per the rib cage, we worked with the best ribs we had available to define the posture of Hatcher, and Steve Jabo did the lion’s work on the actual virtual model with my intern Rebecca Snyder. It is not surprising that other researchers working with different, and presumably better preserved sets would provide alternative solutions, although I like all the new ones a lot, actually.

    • Ralph, I do not think that much would change with regards to the ribcage width – only that personally, I would angle the ribs so that their distal ends are closer. With my Plateosaurus I had a hard time getting the ribcage to make any sense, because of the partly really bad distortion 😦

  2. Ralph Chapman

    Oh, and the project, and other cool stuff, is discussed in detail in the Technology Chapter of the 2nd Edition of The Complete Dinosaur by myself, Art Andersen, Brent Breithaupt and Neffra Matthews.

  3. Great post, a very thorough summary of a complex issue! I love the story of Hatcher’s remaking 🙂 ‘Trike’ posture is a very interesting topic, and looking at my manuscripts-in-progress folder I can tell you that the last word on dinosaurs elbows hasn’t been spoken 😉

    I only take issue with one statement:
    “The result was the world’s first complete digital dinosaur”
    Well, yes, but not really! Hatcher was the first “complete” digital dinosaur in the sense of scientific completeness, i.e. the entire morphology was fully documented digitally. In everyday language, it was pretty much 2/3 of a dinosaur, or maybe only 3/5. After all, the elements present in two handed forms, left and right (limb and girdle bones, ribs), were scanned only from one side.

    OK, what’s the difference, you may ask?
    In fact, with an undeformed skeleton there would be preciously little difference. Some dinosaur finds are hardly deformed, and it really doesn’t matter if you scan the left humerus and mirror it, or if you scan the right humerus. But in most cases, there is quite a difference. I know this from experience; it was no fun trying to get some dinosaur skeletons digitally aligned exactly because of the many deformations that made regularly identically-shaped but mirrored elements totally different from each other.

    Thus, I hold that the first really complete dinosaur (as far as technically possible; the belly ribs were too big for the scanner, the skull much deformed) – published! – was GPIT/RE/7288, a Plateosaurus engelhardti from Trossingen in Germany. That practically complete individual was CT-scanned bone by bone, and digitally mounted.

    • Ralph Chapman

      Disagree on that last point. The Plateosaurus may be the first digital individual dinosaur animal, but the first complete digital dinosaur as a species was Triceratops through Hatcher, Heinrich.

      • Ralph Chapman

        Somehow managed to send reply before done, so here is the final point…
        (Got to compose in Word and copy over from now on).

        But the point you make is fine and both are good steps towards where I’ve been wanting to go since I got my first 3D digitizer at the Smithsonian in the 1980’s. I presume Larry Witmer, Scott Sampson, Art Andersen, Dave Weishampel, the Austin group, etc. were right with me at that time and it is great to see things arrive so heavily lately (and finally).

      • Ralph, exactly – from a science point of view, Hatcher was the first. From an “everyday language” point of view, it was the Plateo.

  4. I greatly enjoyed your two-part treatment of the Triceratops Posture Problem. I followed up on Ralph Chapman’s suggestion about the technology chapter in The Complete Dinosaur (2nd edition). That’s a fascinating read. But, what struck me was the following passage in that chapter: “Museums want to exhibit dinosaur skeletons in a way that excites and energizes their visitors. However, even though it is still commonly done, mounting real bones is no longer a viable option because the process is destructive to the bones themselves in both the short and long term.” (p. 265) Do you agree that including real fossil bones in museum mounts is a practice that should stop? Are any of the major natural history museums on board with this?

    • Ralph Chapman

      It is important to note that the lessons learned from Triceratops concerning the destructiveness of mounting real bone comes from the fact that the original Smithsonian mount was very old compared with almost all mounts these days – mounted in 1907ish. Like the Iguanodon skeletons mounted in the 19th century, they showed the effects of the inevitable variations in temperature and humidity, combined with vibration, that will occur in just about any museum environment and that will lead to pyrite disease of the bone material. That’s not to say you cannot exhibit real bone, it just needs to be in an environment that minimizes these problems such as a vitrine with some environmental/vibration control.

      Mounts can be done much more effectively and with little damage with quality casts backed up with real fossils done in a controlled environment in the same exhibit area. Visitors get to see the real thing and the mount as an interpretation of the fossils. I truly don’t see any plus side to using the fossils themselves in the mounts, especially if they will have to be messed with to do it – and many classic mounts involved a lot of drilling.

      So, I would ask, why damage the fossils when you can do so much without doing it?

      • Ben

        Hi Tony, you’re asking a huge, complicated, and fascinating question that really gets to the core of what museums are about! My impression is that from the perspective of researchers, mounted skeletons are a burden that inhibits access to specimens, and which can often damage them outright. However, many visitors and some museum workers feel strongly that museums need to display authentic fossils, no matter what. The usual argument goes that if people wanted to see reproductions, they can do that at home.

        Of course, it’s also worth exploring what we mean by “authentic” in the first place. Take the two versions of the Smithsonian Triceratops. The original was made mostly from real fossils, but it was a disproportionate chimera assembled from numerous specimens of different ages and sizes, including a few non-Triceratops bones. The new one is made from foam and plastic, but it’s a much better representation of what we know about Triceratops today. Which one is more authentic? Which one is more “real”?

  5. Thanks for these responses to my questions. I am taken aback (as I know you are as well) when, otherwise thoughtful people, take the position that casts of fossils are “fakes” (even if they don’t use that particular pejorative). Which means I was concerned by the comments made by Kirk Johnson, the head of the National Museum of Natural History, about the Wankel T. rex that will be the centerpiece of the NMNH’s new fossil hall when it opens in 2019 (gone will be the T. rex cast called Stan). In a Washington Post article (June 27, 2013), he was quoted as saying, ““Think about what the museum is . . . . It’s a place where real treasures of the natural world are on display. If I said I have a glass replica of the Hope Diamond, you’d be less impressed. . . . It’s really important for us to have a real object for people to see and experience and be amazed by.” Frankly, his comment on the Hope Diamond and a T. rex skeleton is an apples and oranges comparison. Anyway, what was done with Hatcher makes most sense to me – cast of the full skeleton with a selection of real bone on display in a carefully controlled environment. Thanks again for a great blog.

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