Smithsonian National Museum of Natural History

Webinar – Building Dinosaurs: Behind the Scenes

Webinar – Building Dinosaurs: Behind the Scenes

Monday, November 15, 2021

Amanda Sciandra:

All right, let's get going since we have decent amount already in our program. I'm Amanda Sciandra again, After-Hours Program Manager at the National Museum of Natural History. I'm a brown-haired woman wearing a blue shirt in front of a full bookshelf and a window with a plant. And on screen is a photo of our guest, Caitlin Wylie and the date and title of tonight's event, Building Dinosaurs: Behind the Scenes.

Thank you again for joining us. As people continue to trickle in, I'll go through our standard housekeeping notes for those who are new to our programs. First, closed captions are available by clicking the arrow next to the CC button on the Zoom toolbar. You'll also find on that toolbar the Q&A box. This is where you can submit your questions at any time. That Q&A goes by so quickly.

So please help us out by submitting your questions as you have them at any time. And if your question is for someone specific, please let us know when you submit it. Tonight's event is part of our celebration of fossils at NMNH, nine days of fossil programming. Check out the link in the Q&A for more info about our other events.

And for tonight's celebration, we're going behind the scenes with two guests, Vertebrate Fossil Preparator Steve Jabo from the National Museum of Natural History and Assistant Professor of Science, Technology and Society at the University of Virginia and author Caitlin Wylie. Caitlin's new book, "Preparing Dinosaurs: The Work Behind the Scenes," is the subject of tonight's program.

Steve started in the Department of Paleobiology at the Natural History Museum 32 years ago. You'll hear more about this soon. But currently as a fossil preparator in the Vertebrate Paleontology Preparation Lab, Steve plans and conducts field expeditions to discover and collect vertebrate fossils, prepares the fossils, makes them available to researchers and conserves them.

Caitlin Wylie is an Assistant Professor of Science, technology and Society at the University of Virginia. As a social scientist, Caitlin investigates how people create and interpret data, designs research tools and techniques, and construct knowledge in science and engineering. More on what she does soon.

So we'll start with Steve. He'll tell us a little bit about his work as a fossil preparator at the museum. See a little behind the scenes of the Fossil Prep Lab. And then he'll pass it off to Caitlin to tell us about the problem solving and creative work of fossil technicians. After, I will come back on to ask Caitlin and Steve your questions.

So, without further ado, I welcome Steve Jabo. Steve.

Steve Jabo:

Thank you. All right, let's get started here. All right, so I'm going to tell you a little bit about what fossil preparation is and go over a few things that preparators do. So, just what is fossil preparation? What is a preparator? In simple terms, fossil preparation is the process of removing the sediment in which a fossil is embedded, called matrix, to expose the features needed for its study.

Removing matrix can be done in many ways with many tools including digitally. But preparation is also conducting the fieldwork to finding and collecting fossils, is the consolidation and conservation treatments done to a fossil. It's the three-dimensional replication and imaging of fossils, as well as their photography. It's the occasional mounting of fossils for display. It's the use of proper health and safety measures during all preparation activities. And it's the documentation and recording of everything done and used on specimens.

So, a preparator is the person who does all that stuff. There's a fairly broad set of skills to learn to be a good preparator. In fact, here's a long list of 14 skills that a competent preparator should be at least acquainted with. They're called the essential core competencies and they cover every aspect of fossil preparation.

If you're interested in learning more about them, the paper is posted in the Society of Vertebrate Paleontologist website. The link is in the Q&A. Also in the Q&A is the link to the SVP preparators' resources page that has a ton of information for preparators.

Just a quick note about the competency bookends, number one is the most important of all, critical thing, which addresses the proprietor's mindset. It's about thinking through and understanding what you're doing and why you're doing it until the end of the project. And it's about knowing your own limits. And number 14, health and safety is really important, too. Besides being its own competency, there are specific health and components in lots of the other competencies like fieldwork prep, molding, and casting, et cetera.

Great. So moving on, I've listed some of the processes that fossil preparators do. But how do preparators actually do their work? Now, flesh out some of the processes in the order we do them starting with fieldwork. So, you want to go dig a dinosaur. What do you do? How do you find and collect them? Sometimes we get tipped off about fossil fines either by the local residents of an area or by other researchers who worked in an area. Other times, we might have to explore new areas from scratch to find them.

Once you find an area where you want to explore, you have to have all the proper permits and permissions from whoever controls that land. And then you plan your trip. And the big day comes and you set up your field station with all the supplies. It might be a motel. It might be a camp. This is my tent on the Missouri River in Montana with a Late Cretaceous Judith River Formation in the background.

If you don't have any known fossil locations, you're going to have to prospect to find them. Prospecting is systematically walking the outcrops in a search pattern to try to find fossil evidence on the surface like bone fragments eroding off the ground.

This is a nice shot of the Cloverly Formation in the Bighorn Basin in Wyoming, near Sheep Mountain. It's Early Cretaceous, about 115 million years ago. And we get a sense of scale here to some humans. All right, so say you're prospecting and you find something to collect, the first thing you do is shoot it in with a GPS and put the coordinates in your field notebook. You can do the old school way and put a dot on a topographic map.

A field book is vital to have to document everything you do and find in the field. Then from a single bone to large specimens, it's pretty much the same procedures to collect fossils, just different scales. After you determine how big it is, you dig a channel around it to get it up on a pedestal. You cover it with wet paper towels then plaster in burlap. Then you label it with lots of info like the identification, the field number, the year, north arrow, et cetera.

And then you flip it and repeat on the other side. We call this a field jacket. These field jackets here hold the body and tail sections of a Titanosaurus, a dinosaur we found in the Cloverly. A Titanosaurus is herbivorous ornithopod dinosaur best known by being shredded by the toe claws of little medium dinos called Deinonychus. Then you log these jackets back camp and then you ship them home.

All right, once you're back in the lab and you're ready to start prepping your specimen, the first thing you have to do is take some of the plaster field jacket back off. You might use an oscillating saw like this autopsy saw or a cast-cutting saw or an angle grinder to start cutting the burlap and plaster to remove it. You should have a shop back there ideally with a HEPA filter to catch the dust and use eye and hearing protection. You have to be careful not to damage the unseen bone with the saw. So I usually start opening the jacket from the bottom side for that reason.

And once you get the burlap off, then you can assess the condition of the rock and fossil. Start removing matrix. This is where adhesives and consolidants come into play. Two of the most common and accepted consolidants are copolymers called polyvinyl butyral, also known as Butvar B-76 and ethyl methacrylate called Paraloid B-72. Both are dissolved in acetone or ethanol and have slightly different properties.

We make thick mixtures of them dissolved in acetone in big jugs in the lab. And we keep them in a chemical closet. And then we disperse them into smaller squeeze bottles for our personal use in the field and in the lab. We could use them as thick adhesives or we can thin them down with more solvents so they penetrate the cracks of the bone and consolidate it when it dries. Both have long archival lives. It could be redissolved solvent if they need to be softened or removed.

So, for the mechanical prep, you got to start removing the matrix to expose the bone. Some of the most commonly used prep tools are air scribes. They come in different sizes and are basically mini air-powered jackhammers with a carbide tip. You run the scribe parallel to the bone surface to chip away the rock. And you got to be careful not to chip the bone away, too. And you need to wear the proper personal protective equipment, PPE, so rock chips don't fly in your eye.

There are manual prep tools to use, too, like dental picks or these pin vises with needles in them. They could be used with different diameters of tungsten carbide rods. They could be sharpened into variously shaped points like a chisel tip, a flattened cone, a pyramid, whatever the job takes. The needles are used to scrap and poke away the matrix during fine-detailed prep under a microscope. I use a quarter-inch diameter rod down to a sew needle thickness.

And we also try to get microscopic vertebrate fossils out of rock outcrops by collecting bulk matrix from microfossil rich layers in the hillside. These are little Jurassic mammal teeth. Back home, we load up sieves of different grid sizes of the bulk matrix and stack them in this machine, the coarsest mesh which is 4 millimeters wide on top down to the finest mesh which is 0.45 millimeters.

And Duncan was given to us by Macalester College in St. Paul, Minnesota. And gently moves the sieves up and down in water with a little detergent. After a day or so of washing and rinsing, the sieves are dried. And the sieves sort out the remaining rock fossils by size which helps make finding the fossils easier under a microscope. We use a wet brush to pick them up out of the tray and sort them into containers.

We found lots of interesting and important specimens this way, like these tiny dinosaur teeth that were in an Allosaurus' nesting site we've collected in Wyoming. And just to get an idea of how small these are, you see the scale bars there. That's 500 microns, half-a-millimeter wide, so they're super tiny. That's why we go down to 0.45 millimeters. And these tiny little dinosaur bones and vertebrae, the scale bar here is a half-a-centimeter, 5 millimeters.

So now, these cleaned teeth and bones are ready to be studied. All right, we also try to create custom fit housings for all the vertebrate fossils so they can be safely rest on shelves or in drawers and survive many years in the collections. We've developed techniques to create custom fit padded plaster jackets for fossils to rest in. The jackets support the fossils for their entire length and are usually two-sided.

Each side of the cradle is lined with polyester-polyurethane foam to cushion the specimen on the plaster and has feet keep it stable. And this is the femur of a theropod dinosaur Gorgosaurus libratus. The clamshell-style enables a researcher to study one side of the specimen, put the lid on and flip the jacket over and safely study the other side without having to directly hold and manipulate the sometimes delicate fossils.

All identifying info is written on the outside of the jacket, freeze of locating in the collections. Complete a jackets rest safely in the collections for many years and are good protection for shipping. We also make cavity mounts which are custom-shaped cutouts in ethafoam lined with Tyvek for extra cushioning. They have notches where your fingers go to remove the bone from the cavity. They're perfect for drawers and also hold specimen data cards.

These are the hand bones of the duck-billed dinosaur Edmontosaurus annectens. There are links in the Q&A to the AMMP which is the Association for Materials & Methods in Paleontology's YouTube channel that has instructional videos on how to create archival housing. There are also video talks discussing the core competencies there. And the AMMP website link in the Q&A is a good resource for preparators.

A big part of my job is molding and casting fossils to exchange with other institutions for collections or more recently for exhibition. This is an example of a two-sided silicone mold I made to produce this cast of a 4-foot T-Rex pelvic bone called an ischium. We can make large scale molds and cast like a triceratop skull. But we also make molds of tiny fossils like those little dino bones I've showed you.

The arrows on the right show are pointing to the cavities in the mold where the bone sat in the silicone. And the brownish stain is from the colored epoxide I used to make the cast for our Deep Time Exhibit. Molding and casting aren't the only ways to make replicas and visual records of fossils. Ways of imaging have increased over the years. We still photograph specimens for publication and databases.

A 3D imaging is becoming very popular as a research tool. This is a 3D model of the right humerus, the upper arm bone of our Triceratops horridus mounted Hatcher. This was made with a surface scanner and could be scaled up and down and printed in special machines. We also X-ray the humerus. And we're surprised to see that it contained these steel rods inside shown in the picture as the white lines that must have been put in there for strength in the early 1900s.

We also CT scan the humerus and if you look at the cross-section slice from where this red line is, you can see the steel rod in the center, but also a couple of other white spots which indicate areas of very high density or reactive materials. We think that indicates there's pyrite in there and iron sulfide. The black areas are very low to no density spaces like cracks or air pocket.

So, all the things that preparators do and all the materials that are applied to each fossil have to be documented. Each fossil we work on gets this prep log sheet to document what was done to it. The top half records all the identifying information like the catalog number, locality info, genus' and species' name if we know it, and descriptions of the journal bone and matrix conditions.

The lower half records all the tools and materials and methods that were used on the specimen. This is important information in case the materials applied might interfere with certain analyses or if the adhesive has to be undone or to help determine if any unidentified markings on the specimen are manmade.

So, we surface scanned and digitized our triceratops mount back in 1999 to make the first fully 3D dinosaur that we called Hatcher. We were then able to build him bone by bone on the computer in the pose we wanted the cast mount to be. And we used the digital mount to exactly design our steel armature and then cut steel and bend it to those shapes. Then we welded all the steel pieces together in the pose we wanted and attached the cast around the steel to create the new mount and then painted the casts.

Here's the final product Hatcher as he stood in the previous fossil hall at the museum. So that's quick run through of the things that preparators do to fossils in the course of their work so they can be studied so they can last a long time in the collections. I'm going to show you a few things around that are happening around the lab right now.

All right, we're all good?

Amanda Sciandra:


Steve Jabo:

Okay. This is one thing that's being prepped here in the Fossil Lab that is the pelvis of the Edmontosaurus annectens that was on display. You can see there's a lot of steel armature on it still from where it was attached to the wall. So we have to take all that armature off. We have to chip all this plaster off.

I don't know if you can see the steel pipe running across there. So, that's a big project and it's a big pelvis, too. We've built all these temporary structures there to protect the bone while we're working on it so nothing breaks while we're chipping all that plaster and rock away. There's still even fossil ... sorry, rock matrix stuck in there.

I'm moving over here. There's some housing happening here. This is a little Mosasaur, piece of a Mosasaur jaw. You can see the old label. So that has that cavity mounts that we were talking about. And moving over this way, we have a Camera Lucida set up. So, this little bone is being drawn. There's a tiny little vertebra there that's being drawn on the side. We can see some of the other stuff that is being drawn. This is for scientific illustration. They're exact scaled replicas drawings of these things. And the stapling is really cool.

Over on this side, this is something I was just doing just a couple of minutes ago. There's a tiny little specimen under here that I'm photographing. And there's a photograph. These are the teeth of this little guy. You can see the scale bars, 1 millimeter. So you need this really nice set up here to photograph these things and keep them in focus.

Here's some conservation jacketing being made. I don't know what's under there, a big bone, looks like a ... I'm going to guess a mammoth tibia that's being jacketed. And it's just getting the first part of the jacket being made in the big sandbox here. Here's another little fun, small sandbox. We use this abrasive garnet sand to work with because it's not a silica sand so we don't get silica dust that we might potentially breathe in.

These are Stegosaurus vertebrae that are being housed in cavity amounts and special custom housings. So, let me go back to this. Now, it's my great pleasure to turn it over to Caitlin. Thank you.

Caitlin Wylie:

Thank you, Steve. It's an honor to share the screen today with Steve who is a renowned fossil preparator and an excellent human being. So, this is a dream come true to launch this book with you today and with the Smithsonian. So thank you for being here. I'm going to show you some slides.

So, I am a social scientist in the field of science and technology studies which means that I study science as a social and cultural activity. And I investigated this question on the slide about what we can learn from fossil preparators about science by doing participant observation in 14 fossil prep labs. One of which is fossil lab in this picture which is Steve's lab. This was before the renovation. It looks a little different.

And so basically, this research method means that I hung out and talked to people about their work and I watched them. So that's me in the middle talking to volunteers in Fossil Lab while they're working on fossils. So I wrote a book about out this research as you heard. And MIT press published it in August. It is open access so you can go and read it for free online right now.

You can also buy a paperback. So, I learned two crucial things from fossil preparators about science in practice. The first thing is it is really hard to make nature researchable. So, you saw all of Steve's stiffs from collecting the fossil in the field and then many, many things that have to happen to make it accessible to scientists, so, literally visible and strong enough to handle to touch. Otherwise, if it crumbles, that's not going to be any use to anybody.

And so, what Steve didn't tell you is that every one of those steps requires enormous skill and expertise to accomplish. And so, many of you are asking in the chat, "How do you tell the difference between fossil and rock?" And yeah, exactly, that's the right question to be asking.

So in this picture, you can see this gorgeous fish skeleton emerging out of this rock. The rock in this picture is light colored and the fossil is dark which is very helpful for telling what is rock and what is fossil. But that's not always the case because, of course, fossils are rocks. And so the rock around them and the fossil themselves can look very much the same.

It also means that sometimes there's not really a separation between them. So it's really hard as Steve said to flake off just the rock and not the bone. So I love this picture because the preparator, you can just see at the tip of her tool there, is taking off tiny bits of this lighter colored rock, very slowly, very precisely so that she can reveal this fish to be studied without causing any damage.

So yeah, all of this work is incredibly interesting and common I would argue to various kinds of science, not just fossils and fossil research. So, other scientists talk about it as determining data versus noise, signal versus noise, deciding what is important to keep, what is invaluable scientific data and what is in the way. And so in this case, the thing that's in the way is rock.

And so, all scientific disciplines must prepare nature into data which then scientists interpret to produce knowledge about nature. And sometimes this work is done by scientists. But more often, it's done by technicians and volunteers and students. And so, I had a question about this. Who are these people and what are they doing? And how does it matter for scientific knowledge?

So, there's a narrative that scientists tell that the work of preparing data is grunt work or it's purely technical. Okay. And so they use words to describe data preparators that they are equivalent or interchangeable, or even part of the instrument to be calibrated. So these very mechanical metaphors to describe people, humans. And scientists do this because they want us to think that they're not studying data, they're studying nature in its pure form, that it doesn't matter. It's irrelevant who has taken the rock off that piece of nature to the scientific results.

And as a result of this narrative, technicians and this work of preparing data is often invisible or missing in scientific papers and in museum exhibits. And so, if you look at this picture of Steve holding a foot bone from a T-Rex, you might think, "Yeah, that looks really simple. He's just moving a bone. Anybody could do that." You would be wrong. If you or I picked up that bone, it would crumble. And that's because vertebrate fossils tend to be very heavy yet very fragile so they can crumble under their own weight.

And, of course, they're riddled with cracks because of the process of fossilization. And so in this case, you can see how Steve is holding it in a way that distributes the weight. He knows where the weak points are in that fossil and he's paying close attention to them. You can see he's looking at it. He's not distracted. And he is about to lay it in the sandbox full of that red garnet sand he was telling you about.

And as you heard, preparators carefully select the kind of sand they use to support fossils for, in this case, avoiding dust. So even though this might look simple, it's not. And it relies on a lot of experience to know how to do this work well.

So, scientists know this. Scientists know that the success of their research relies on how their data is prepared. So, if you've read Hope Jahren's bestselling memoir Lab Girl, it's owed to her technician Bill whom she negotiates a job for at every university she works at as a paleobotanist because she knows that his expertise is key to her success as a scientist.

And so, the way that preparators talk about this, Steve called it critical thinking. They also call it creative problem solving, so this mindset of approaching a fossil in its context and being able to assess how exactly to handle that fossil to produce the best possible data. And that's in the long term as you heard. These specimens sit on museum shelves for centuries, hopefully. And the ability to make all of those micro-decisions along the way is key to producing good fossil data.

And so in this image, this is the preparator working on that fish that I showed you before. Notice that she's working inside a custom-built box and that's to control the dust and keep it out of her face. Notice how she's carefully positioned the lights and the microscope so that she can see the fossil very well.

Yeah, I mean photographs in fossil prep labs never come out well because they have such bright lights. But trust me, that's fish underneath her tool. And then notice her arm is resting on a sandbag to give her more control, more precision. Yeah. So, lots of micro-decisions that aren't apparent to the rest of us, but that are absolutely crucial to how fossil data look.

So, this work led me to realize that research relies on the work of lots of kinds of people, not just scientists, not just people with science degrees, not just people with jobs in research. So, this is the cover of my book and you can see it's this cute dinosaur. You can tell it's been prepared for display because you can see it's assembled into a skeleton. You can see the metal armature that's holding it together. It looks a lot like Hatcher.

You can see that there's some fossil bone and some replacement material, probably plaster. But really, the more interesting part of this photo is missing from my cover. So, this is the whole photo that MIT press took just one chunk of to make this cover. And crucially, this is Norman Ross. He's a preparator at the National Museum of Natural History.

He's in the prep lab in 1921, so a hundred years ago. He's stringing together vertebrae to make the tail of this little dinosaur. You can see his tools scattered around. You can see bones lying on the table. There's a bowl of something, maybe plaster, maybe glue. It doesn't look so different from Fossil Lab today.

So really, the point of my book is to zoom out from the dinosaurs that get so much attention in science and in pop culture to pay attention to how people work with fossils to make it possible to learn about dinosaurs. All right, so these two insights, one that it's really hard to make nature researchable and, two that science relies on a variety of people. To achieve that goal led me to propose a new framework for understanding how our society creates knowledge about nature.

And so in my field, we talk a lot about constructing knowledge or producing knowledge. And this is my framework, preparing knowledge. And really what I'm trying to highlight here is that the process of making knowledge is iterative. We propose a scientific fact. We're totally convinced and then something happens. We get new data and we come up with a new interpretation to explain the existing data. And then we believe a totally different fact or theory to explain it.

And so, I wanted to capture that aspect of vertebrate paleontology through this metaphor of preparing because you never finish preparing. Preparing is about the process. It's the journey, not the destination. And I think that's true of science too. That science is never going to be finished. We're never going to know all the things about nature because we keep revising it and learning more.

And so, the benefit I think of thinking about science as the process of preparing knowledge is that it gives us a view of science that is more inclusive and participatory because it calls attention to all of these people who are involved who make crucial contributions beyond the scientists.

So, my framework has four components and we talked already about preparing evidence. And basically, all of these things work together to prepare knowledge. So, let me tell you about how fossil preparators prepare or define really their sense of community. What does it mean to be a fossil preparator and how do you become one?

So, this image on the right is a series of what are called prep tests. So if you show up at a fossil lab and you want to volunteer or apply for a job, the preparators will hand you a fossil and a tool and say, "Take the rock off." Okay. No training, no explanation. You probably have no experience. And they do this on purpose because preparators believe that to be a good preparator, you need to have a couple of skills already that you cannot learn. They have to be innate.

And those skills are attention to detail, patience, and manual skills, so fine motor skills. And if you have those things and you prove it by preparing this little fishtail, then they'll take you on and train you in the rest of the whole myriad list of things that fossil preparators do that Steve told you. So in this case, this box is some examples of good fossil prep tests because you can see the bone. They're dark. There's no scratches. There's no chunks of bone missing.

And then these are all sort of varying degrees of failure. And this is a gigantic failure. So the volunteer here prepared away most of this bone. And so, I imagine this person was not invited to join the prep lab. So, say that you passed the prep test. You've proved yourself as a potential preparator. The next crucial skill you need to learn is to be able to distinguish fossil from rock.

And the way that preparators teach this is they basically encourage volunteers or applicants, whatever, novices, learners to prepare a fossil and pay really close attention. So you spend a lot of hours staring at a fossil. Preparators come over and give you advice. Correct you, supervise you. And over time, you pick it up. It's experience based.

So, in this example on the left, the preparator's pointing at the jaw of a lizard. So, I can't see this. You probably can't see this. Really, you can only see the shadow in this picture because it's already been prepared out a little bit. So my point here is that even deciding what is specimen and what is not specimen is evidence of preparator's deep skill.

So, Steve and his colleagues wrote really the only paper on how to train fossil preparators with regards to how they train volunteers to work in the Fossil Lab at the National Museum. And so, this phrases a question or the point I want to make about volunteers which is that vertebrate paleontology absolutely depends on volunteers. And this is true not just for their free labor but because it's free, very skillful labor.

They're not going to let people work on a fossil who don't have the skills to prepare it well. And that is crucial for providing specimens for the scientists. It also helps the museum achieve its goal of outreach and education by serving these volunteers. Crucially though, the thing that I think get overlooked is that volunteers empower preparators by making them into trainers and managers of a workforce. Okay. So not many technicians get to control their own workforce of people and fossil preparators do. So that's a crucial part of their professional identity, too.

Okay. So each chapter in my book is about one of these components. So, I'll tell you about Chapter Three which is preparing technologies. So basically, I mean by that tools and techniques. And the fascinating thing about preparation tools is that they are remarkably stable. They have not changed much at all over the course of human history.

So this figure is from a paper by preparator Matt Brown. The image on the left is a drawing of prep tools collected in a lab in 1909. And then Brown recreated the same image with tools in his lab in 2009, making the point that in a century, preparators are using essentially the same tools.

And the interesting thing about this is that preparation tools are incredibly flexible, modifiable. And that's what makes them last so long. So you heard from Steve about the importance of pin vises and chisels and air scribes. And this is an image from a paper by preparator Connie Van Beek where she's teaching others how to carve the tip of these needles to fit into particular fossil crevices to get the rock out. Okay. So, she's altering the shape of these tools to meet whatever need she has for each specimen. So it's that ability to adapt and modify technologies as appropriate to the fossil that makes preparators experts.

So yeah, this is also true for air scribes. This is schematic from the first paper about air scribes which was published in 1903, which was an adaptation of stone mason's pneumatic hammer. And you heard from Steve how crucial glue is to the success of vertebrate paleontology because, of course, these specimens are so fragile.

And so again, preparators know exactly what kind of glue, what chemicals solution they want to use. They know how to dilute it to the particular consistency that they want. And again, it's very modifiable, it's flexible and it really relies on the preparator to make this technology work.

So, for example, these are two skulls of the same species collected at the same place at the same time. So they should look the same. They do not look the same and that's because they were prepared about 50 years apart. So the one on the left you can see has a really smooth bone surface. You can see all the holes and where things would have connected in life.

And the one on the right has a lot of surface damage which was caused not by the tools but by a difference in expertise. So by the 1980s, preparators had become professionalized. In the 1930s, anyone was preparing fossils. So here, I'm making the argument that it's not the tools that matter, it's the technician.

And then I learned about CT scanning and I thought, "Wow, this is the end of fossil preparation." If you can noninvasively see inside rock, you could spare a specimen the risk of damage from physical preparation. So here's a dinosaur eggshell. Here's an image of what's inside it, the bones of the embryo using CT data.

But scientists disagreed with me, they were skeptical of digital images. They really trusted a physical, visible fossil prepared by an expert preparator. They prefer that as their data source which is really interesting. It shows you the importance of technicians' expertise and the importance of scientists' trust in the people who are creating their data.

All right, so vertebrate paleontology has a really interesting way of defining what science is for the public. And that is these glass-walled labs where visitors can go and watch preparators at work. So here's the old fossil lab from the outside. So imagine you're the visitor, what portrayal of science do display labs like this provide?

So you look inside, you see people bent over fossils with their buzzing tools. But you also see people talking to each other, people laughing, people wearing normal clothes, drinking coffee. You see their tools. You see lots of dirt. So things you aren't really used to seeing on display in a museum. Crucially, it's showing science as work, as a process. It's not just these finished facts that are on the display, the text panels that seemed very authoritative. Rather, it's humans at work doing science.

Also, most preparators in glass-walled labs are volunteers. And so they are actual members of the public, just like you and me. And this helps portray science not as elite or exclusive, but as welcoming. And labs like this illustrate that museums house research. Okay. They don't just house dead things. It's an ongoing space of knowledge production or knowledge preparation.

And my favorite thing about these labs is that they invite visitors to conduct scientific thinking themselves. Okay. So you walk up as a visitor and you think, "What am I seeing? What are they doing? What's in that jar?" And then you can draw evidence-based conclusions. And so these conclusions are not always the same conclusions that preparators would like.

For example, I saw one person approach a lab like this with a little kid. And the person said with great excitement, "Look, people making fossils," which is, of course, not what they were doing but you can imagine where that idea came from. There's plaster everywhere. There's carving tools. So, you can see the evidence that she used to draw this wrong conclusion. And so I think that's a major goal of museums, to get the rest of us to think like scientists.

So here are some more images from Fossil Lab. Notice how close the visitors are. Okay. So here's the visitor, here's little kid. Here's the preparators at work. So it's up close and personal view. Here's a coffee cup. Here's somebody's snack. Here's a cast of a fossil. Here's a printout of information about that specimen that the volunteer made so that people outside can read about the specimen that she's working on.

And also, notice they're ignoring the visitors. This is not a demonstration. They're not doing this work for the benefit of the public alone. They're doing it for the benefit of science to create scientific specimens, not create, prepare scientific specimens for research.

And so here's another view showing an image down the microscope so that you can actually see. Here's the preparator. Here's the fossil. And this is what the preparator is seeing. So there's his tool tip. Here's the light-colored rock against the dark-colored fossil. So, lots of opportunities to ask questions of yourself. Here are some visitors watching.

So, I want to make the argument then that thinking about research as the work of preparing knowledge can help us all understand science as more welcoming, more participatory, more inclusive. And encourage us to join in so we could become technicians based on our skills rather than our credentials necessarily. We could become volunteers. We could practice citizen science.

Participating in scientific work or even just watching it as somebody else's work can improve how well we nonscientists understand and trust science. And it can help scientists learn from us how to do research that is socially relevant and accessible. Thanks.

So, Steve and Amanda are going to come back on and we will start your questions.

Amanda Sciandra:

Hello. All right, let me get these views going so everyone can see everyone. That should work pretty good. Okay. Thank you so much, Steve and Caitlin. I haven't been in the museum in a while, so it was really fun to look around with you, Steve and Caitlin.

Now, I have such a greater appreciation for the beautiful specimens in the fossil halls knowing everything that has gone on behind the scenes. As a reminder to the audience, please feel free to ask your questions in the Q&A box found at the top or bottom of your screen at any time. We already have a lot. So, let's see how many we can get through here.

Let me just start by asking real quick in case it wasn't obvious already, how do you two know each other? Caitlin?

Steve Jabo:

Do you want to take that, Caitlin?

Caitlin Wylie:

Sure. I met Steve at a conference for what became the Association for Materials & Methods in Paleontology. And I gave a talk and he said, "Hey, do you want to come study our museum?" And I said, "Yes, please."

Amanda Sciandra:

Great. Thank you. Because you guys know each other but maybe everyone didn't know that you knew each other and how. So, I want to start with just a baseline question. I know that both of you mentioned how to tell the difference between rock and fossil. But maybe, Steve, you could just clarify how you tell if something is a fossil to start.

Steve Jabo:

That's a good question. It actually doesn't take as long as you think to get the eye. So, every locality has different colored combinations and textured combinations. Like in the Cloverly, you might be looking at gray rocks with a purplish-looking fossil that might come out of it.

So, color distinction is the first thing. But then, my hand lens is always in my hand. And so, if I'm not sure something is a fossil, I can look at it and look at the texture. The bone structure is still there. The original hydroxyapatite bone structure is still there. It's just been altered a little bit and infilled with matrix. And so, if you can see some of that bone structure, that's a good clue.

A lot of petrified wood looks like fossil bone, too, so that's a little bit of a tricky thing. I think I saw somebody say licking fossils, we do that all the time. I don't recommend it because you don't know where that fossil's been. But I do that all the time in the field. If it sticks to your tongue, it's a fossil most of the time because they're still a little bit porous and it will stick to your tongue. Petrified wood or rocks just won't do that because they're more solidified.

Amanda Sciandra:

So the five-second rule certainly does not apply here.

Steve Jabo:

It does not. But again, health and safety wise, I don't recommend doing that but you end up spitting a lot in the field. But that's the main thing is you get ... then your eye becomes accustomed to finding things. And then suddenly, it's paying attention to those details of what you see on the ground might be a fossil.

Amanda Sciandra:

Thank you. Okay. So, this question is from Dana. It's for potentially both of you. Steve, if you want to start. And Caitlin, you can weigh in, too. Question from Dana says, as I understand it, most of the fossilized dinosaur skeletons found are incomplete. On average, what's a typical percentage of a skeleton found? And are there often mixtures of species in a given site? Over time, how have these factors affected interpretation of what's been found?

Steve Jabo:

Wow, great question. And yes, the short answer is yes. I don't know if there's ever been a complete dinosaur found, I imagine there has been. But over the, ya know, so much has to happen just for that fossil to be found and discovered in the first place. It has to be buried pretty quickly after death. Otherwise, it will get scavenged there. You have bone loss there instantly.

Then it has to get fossilized. Then it has to be preserved in a long time. Then it has to get back up to the surface and then somebody has to find it. So, for dinosaurs, there are just so many bones and not all of them get preserved. Some of them were skull bones especially are very thin. The teeth get preserved much better because they're strong enamel. But very thin bones don't get preserved that well. Heads pop off and go downstream.

Usually, they're deposited in a river system or some sort of flooding system where there's mud that covers them pretty quickly. And so yes, you can get ... some quarries have multiple skeletons and of multiple species. There are some really famous ones like Canon city. And there's sauropods mixed in with theropods and other sorts of different kinds of dinosaurs all jumbled together.

And so you make a quarry map. When you start getting ... but you say, "Okay, this is this species. This is this. Oh wait, we have three left femurs. So there's probably three different skeletons in here." And then you try to figure out what is what in the bone pile. I'm kind of rambling. I don't know if I've answered the question. But you do get those situations where there's a lot of different animals preserved in the same spot.

Amanda Sciandra:

Like a jigsaw puzzle and detective work and science all rolled into one.

Steve Jabo:

And you don't know if you have all the puzzle pieces there. You might have extras to a different puzzle.

Amanda Sciandra:

That's why we have you and the experts. Speaking of experts, Caitlin, this question is for you from Matthew. Because preparators tend to have a variety of degrees, bachelors through Ph.D., from fields related to paleontology, how do you distinguish preparators from paleontologists? Are they degrees apart and not distinct units?

And then there's also another question related to this that I'm going to tag on here from Joe. What fraction of scientists in this field started their career as preparators or technicians? I can repeat either of those if you want me to.

Caitlin Wylie:

Yeah, thanks. Hi, Matt. Matt is another renowned fossil preparator so he knows the answer to this question. But yeah, I would say that that's actually something I cut out of this talk. So part of preparing a conception of science is that you have to prepare one within your community so that the preparators understand what the scientists are doing and what they're doing together.

So, I was thinking of science as the thing that preparators and paleontologists do together. So that's the thing that holds together these otherwise fairly different groups of people. So yeah, as Matt said, preparators have a wide variety of educational backgrounds. There's no specific credential to become a fossil preparator.

As we know, there are lots of specific credentials. You need to be a paleontologist. And so, paleontologists and preparators think that they're very different. So they identify as belonging to very different fields. Do they have formal ways of telling this, like credentials, who has a PhD and what is your job title and what is your salary? Those are really different between preparators and scientists.

And then, they have informal ways of indicating which community they belong to. And my favorite is through language. So for example, preparators nickname fossils. And so, as you heard, you met Hatcher. So I saw a lot of preparators nickname the fossils they're working on partly out of affection. You're looking at them for many hours in a day.

And when they were talking to scientists, the preparators would say, "You know, the Triceratops." They would drop the nickname. And so there's little things that they do to distinguish themselves from each other. And they also have a very strong sense of division of labor. So preparators get really offended when scientists try to prepare fossils because the preparators think that the scientists don't do it as well as a preparator which is true.

And then scientists get really upset when preparators try to publish scientific research. Okay. So there's this territoriality between the two groups. But, of course, they totally rely on each other. They need each other.

Amanda Sciandra:

Of course, an ecosystem. Speaking of specimens that are named, there's a question here from Deb about one of my favorite named specimen. Question is for Steve. Do you have any idea how long it took preparators to clean and mount Sue the T-Rex at the Field Museum?

Steve Jabo:

Oh boy. That's a good question for the folks at the Field Museum. I know it took years. And I know they had two separate facilities, one in Florida and one in Chicago. And there were a lot of people working on it at the same time. So, I don't know the number of hours but it was in the order of years to get that thing fully done. Maybe Caitlin knows better than I do. I don't know.

Amanda Sciandra:

Caitlin, do you know?

Caitlin Wylie:

It was many years. And my favorite thing about Sue is that they prepared most of her, it, in glass-walled labs. And they made T-shirts. The preparators made T-shirts that said, "Sue, we built her."

Amanda Sciandra:

Love it. I love Sue. There's actually another question about naming. Steve, why is your separating machine called Duncan? If there's a quick answer to that because there are so many questions. I want to get to all of them.

Steve Jabo:

So, we got it from Macalester College and Duncan is a good Scottish name and it dunks. So, it's on multiple levels.

Amanda Sciandra:

So creative. I'm glad I asked. Thank you to Riley for asking that question. Okay. This question is from Cosette who identified as being seven years old. Maybe you could answer quickly, where do you like to go to look for fossils? Do you have a favorite place to go?

And another seven-year-old named Emma asked, would like to know how much fossils weigh and how they're best transported when they're heavy? And I think actually, there's another question. She would also like to know where we can find display labs like the ones we've seen in the presentation today. So, I know that answer but, Steve, go ahead.

Steve Jabo:

Okay. I'll talk about where we go to find them. I've been working in the Bighorn Basin in Wyoming for a long time for 20-some years. And so, that has everything you need. It's got all the formations you would want to look at. And there's a lot of bureau of land management land there that is easier for us to work on because it's federal and there's just fossils. There's lots of fossils there.

We've got to know the people out there very well. And so, it's like our second home out in Wyoming. So that's probably my favorite spot. But really anywhere where there's something coming out of the ground, that's always a good place to go. What was the second part of that?

Amanda Sciandra:

The second part was how much fossils weigh and how are they best transported when they're heavy.

Steve Jabo:

Right. So they are heavy. They're a lot heavier than you think because they're full of matrix and the cement that holds the matrix together. So they're as heavy as a rock. They're not quite rocks but because of that, the mineral is still in there. The bone structure is still in there. But they've been remineralized and so they become very heavy.

But like Caitlin said, it's like the worst of both worlds. They're super heavy and super fragile. A lot of them because of the geology, they have cracks in them so if you pick them up the wrong way, they'll break in your hand. So, the best way to transport them is if you can make a little jacket like I showed you those little clamshell jackets, even just a single-sided cradle, that's the best way to transport them in a vehicle of some sort.

Amanda Sciandra:

Thank you.

Steve Jabo:

Caitlin knows better about the different labs around, I think, that you visited.

Amanda Sciandra:

Yeah. There was someone in California asking if there was anything on the west coast that you know of.

Caitlin Wylie:

Yeah. La Brea Tar Pits. LA Museum has a glass-walled lab. The Denver Museum has an amazing glass-walled lab. Yeah. There's a bunch great.

Amanda Sciandra:

Great. Lots of good opportunities.

Steve Jabo:

Yeah, the Field Museum.

Amanda Sciandra:

Caitlin, there's a question for you from Lisa. What kind of feedback have you gotten from paleontologists on the research, any pushback from the concept of more inclusivity in credit for the process?

Caitlin Wylie:

Lisa Herzog, another renowned preparator. I'm so glad so many of you are here. Yeah. Lisa. So, I started this project thinking that I was going to liberate preparators that I was going to empower the masses in a Marxist view. And I quickly abandoned that perspective because I realized how much power preparators actually have in practice.

So they control the workforce. They train volunteers. They decide how to prepare fossils. They modify their tools as we talked about. And that's enough for them. They're very satisfied, generally speaking. Most of them are satisfied with that amount of power.

And so, being authors on scientific publications doesn't mean that much to them, not all of them, but most of them are not in it to write papers. They're in it to make these fossils that will last for a long time. And so, I worry actually that if we made preparators authors on papers, then they would lose that autonomy over their work because scientists would then want to be involved.

If they're going to have to describe prep methods in a paper, then scientists are going to want to know. They're going to want to say to Steve, "You know, I think you should use this glue." And Steve would be horrified that a scientist would tell him that. So yeah, that's my thought. I'm not pushing for authorship, but I am pushing for better documentation as is Steve, as is Lisa so that their work gets preserved in specimen records to help out scientists in the future, and also so that they get the credit. So that the museum can some say Steve Jabo prepared 7,500 fossils over his career.

Amanda Sciandra:

Thank you.

Steve Jabo:

That reminds me. There's another great exhibit lab in Raleigh, North Carolina, it's a state museum.

Amanda Sciandra:

Thank you.

Caitlin Wylie:

And in Carnegie, that's in Philadelphia.

Amanda Sciandra:

We actually only have time for one more question. And I'm going to allow this one to Steve. We've learned about the 3D printers and the CT scans today. Are there other techniques that Natural History is leading in the fossil preparation field that we should know about?

Steve Jabo:

Not that I can think of off the top of my head. Yeah. I guess that's the short answer.

Amanda Sciandra:

Let me ask one more. We've got time for one more. I'll ask you both what you're working on now or what you're working on next, something you're excited about. Steve, you go first and we'll end on you Caitlin.

Steve Jabo:

Okay. I'm working on a whale skull that was collected offshore British Columbia. It's an aligasin whale right in the transition between toothed and baleen whale. So, I'm prepping that out of a big nodule for Nick Pyenson here at the museum. Pretty interesting.

Amanda Sciandra:

Caitlin, what are you working on?

Caitlin Wylie:

I am building on this study of technicians to look at other contributors to scientific knowledge. So I've done a lot of research on undergraduate researchers. So, undergraduate engineers who work in research labs and how they bring new knowledge and new ideas to experienced professors.

And I'm also looking at the role of volunteers in citizen science projects to again think about what is the value of including a broader range of people in scientific work?

Amanda Sciandra:

I bet a lot of our participants or attendees tonight would appreciate that because I bet there are a lot of volunteers and citizen scientists out there.

Caitlin Wylie:

You're awesome.

Amanda Sciandra:

That's pretty much all the time we have. Please join me in thanking Caitlin and Steve. I also like to give special thanks to those who made today's program possible, our donors, volunteers, and all of you viewers out there, all of our partners who help us reach, educate and empower millions of people around the world. Thank you so much.

Amanda Sciandra:

Don't forget to check out the rest of the Celebration of Fossils lineup that you see on your screen now. The link is also in the Q&A. And the next event is on Wednesday, November 17th from 2:00 to 3:00 pm. It's an Expert is Online Program with Myria Perez. So, definitely go and sign yourself up.

Amanda Sciandra:

You'll also see a link to a survey. We hope you'll take a moment to respond. We are very interested in your input. Thanks again and hope to see you next time.

Caitlin Wylie:

Thank you.

Steve Jabo:

Thank you.

Archived Webinar

This Zoom webinar with author Caitlin Wylie aired November 15, 2021, as part of the "A Celebration of Fossils 2021" series. Watch a recording in the player above.

Accessibility Notes

  • This video includes closed captions and American Sign Language interpretation.


The iconic dinosaur skeletons we see in museums didn't just wake up like this. It takes a whole team of fossil preparators — technicians who painstakingly remove the fossils from rock, repair broken bones, and reconstruct missing pieces — to create them. These specimens are foundational evidence for paleontologists, and yet the work and workers in fossil preparation labs go largely unacknowledged in publications and specimen records. Not any more, thanks to a new book by Caitlin Wylie.

In "Preparing Dinosaurs: The Work behind the Scenes," Wylie investigates the creativity, problem-solving, and craft required of fossil preparators to decide what fossils, and therefore dinosaurs, look like. Wylie is an Assistant Professor of Science, Technology, and Society at the University of Virginia. Join us for a conversation with Wylie, moderated by Steve Jabo, Vertebrate Fossil Preparator at the Smithsonian’s National Museum of Natural History.

Host: Amanda Sciandra, a public programs coordinator at the National Museum of Natural History.

Related Resources

Resource Type
Videos and Webcasts
Grade Level
Paleontology, Anthropology and Social Studies
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