Using Dinosaur Models to Learn More About Their Behavior

Digital 3D Models of Theropod Dinosaurs for Approaching Body Mass Distribution and Volume

by: Matías Reolid, Francisco J. Cardenal , Jesús Reolid

Summarized by: Makayla Palm 

What data were used? This study picked physical dinosaur models from eight different genera, or groups of dinosaur species, to scan and create 3D computer models. These models were used, alongside measurements collected from previous studies on each genus, in order to infer how these dinosaurs may have hunted, moved, and lived. The eight genera in the study were: Coelophysis, Dilophosaurus, Ceratosaurus, Allosaurus, Carnotautus, Baryonyx, Tyrannosaurus, and Giganotosaurus

Methods: Each model was scanned by a 3D printer in order to make a digital image. After the eight models were scanned, data on body length, collected in other studies, was added to the models. information was used in order to calculate body mass, volume, and skull length. These calculations were then used to make three ratios: skull length/body length, surface area/volume, and length/mass. 

Results: The three ratios calculated, skull length/body length, length/mass, and surface area/volume reveal information about these genera that wouldn’t be easily found by just observing the fossils, such as metabolism, eating habits, and overall roles in the ecosystem. The study first looks at the skull length/body length ratio. The larger a skull the dinosaur had, the larger and more expansive their jaws were. This is directly correlated to a higher demand for energy and higher body mass; a large skull was required to take down enough prey to fulfill energy demands. . If a dinosaur had a smaller skull, it was less equipped to take down larger prey, so this limits the kind of prey it had access to. In the case of Coelophysis, the oldest and smallest genus in the study, its skull/body length ratio infers that its small jaws were suited to smaller prey on land, but also small fish. In contrast, the larger theropods, Tyrannosaurus and Giganotosaurus, had the ability to hunt larger prey because of their large skull/body ratio. 

The next ratio observed was the length/mass ratio. This ratio considers differences in body plan that the skull/body length ratio does not. For example, Carnotaurus had a short skull in comparison to the other genera in the study, so it is the outlier in the group. However, the length/mass ratio accounts for its build, which recognizes its ability to hunt larger prey. Similarly, Baryonyx has one of the largest skull/body length ratios, but its long snout shape, similar to modern crocodiles, suggests it fed exclusively on fish and other swimming organisms, rather than large land-living prey. This ratio also sheds light on locomotion possibilities for these theropods. Allosaurus, a mid-size theropod, had longer arms than most other large dinosaurs like Tyrannosaurus. This suggests it may have used its arms when taking down large prey unlike its larger theropod comparisons, which are famous for their seemingly useless arms. 

The final ratio observed in this study is the surface area/volume ratio. This was used to study the efficiency of the dinosaurs to release excess heat, which has strong implications for metabolism. If an organism can release heat efficiently, it can have a higher metabolism, because high-metabolism organisms need that heat release. Researchers found that the smaller the dinosaur, the higher heat release, therefore a high metabolism and vice versa. This is consistent with the study’s findings on feeding habits. Coelophysis preyed on smaller organisms, but was probably able to do so more frequently. Tyrannosaurus hunted larger prey, but most likely needed to rest in between for significant periods of time because of its slower metabolism. 

A scatter-plot graph represents the different body mass and skull/body ratios of each theropod dinosaur genus . The overall trend is a positive exponential growth, which represents a consistent increase in these ratios over time, with Carnotaurus as the outlier because of its shorter skull shape. Coelophysis, the smallest of the studied genera, has the smallest body mass and skull-to-body length ratio and plots on the x-axis. Dilophosaurus, Ceratosaurus, Baryonyx, Allosaurus, Giganotosaurus and Tyrannosaurus all follow the curve of the graph and are listed here in order from smallest to largest skull to body length ratios. Carnotaurus, the outlier on the graph, has a point on the graph that lies close to the origin despite its slightly larger body mass.
This scatter plot displays each dinosaur’s body weight by skull-to-body ratio. As body weight increases, so does the skull/body length ratio. The outlier in the group is Carnotaurus, as its shorter skull gives it a smaller skull/body length ratio.

Why is this study important? This study allows observations of theropod dinosaurs to be made that would not be possible from studying just the bones. This data strengthens previous ideas about theropod behavior, such as larger dinosaurs need more energy and need to hunt larger prey. Therefore, their body structure is reflective of a creature able to take down the kind of prey it needs. This study also provides new information previously not available because of new data about metabolism and body surface area, such as a surface area/volume ratio, which indicates what dinosaur metabolism may have been. 

The big picture: This study of 3D scans of theropod dinosaurs infer information from new data by scanning to scale models. These data allow researchers to compare new measurements like surface area and volume to better understand what dinosaur metabolisms and body plans may have been like, which may confirm or reform what we already know about their roles in their respective environments. 

Citation: Reolid, Matías, et al. “Digital 3D Models of Theropods for Approaching Body-Mass Distribution and Volume.” Journal of Iberian Geology, vol. 47, no. 4, 2021, pp. 599–624., https://doi.org/10.1007/s41513-021-00172-1. 

Makayla Palm, Science Communicator

Young woman with long, braided hair in a black jacket, black ball cap with a backpack stands in front of a large fish skull in a display case. She is holding up two fingers, representing her second year at the event where the photo was taken.Tell us a bit about yourself.
I am currently a junior in college. I am a transfer student; this summer, I am getting ready to transfer to Augustana College  as a geology major from community college. While in community college, I published a couple of pieces in a literary magazine. The first is a creative work called Cole Hollow Road, and the other is a personal reflection piece called Est. 2001, Discovered 2021. Est. 2001, Discovered 2021 reflects on my mental health and growing into who I am. I work about 30 hours a week at a retail store called Blain’s Farm and Fleet. I have been working there since October of 2020. I work in Men’s Clothing, and I mainly sell denim jeans and work boots. With the little free time I have, I explore the outdoors with Noah, my boyfriend, work on my unpublished novel, The Gamemaker,  read books on science communication, and write articles while participating in the Time Scavengers VIP SciComm Internship.

What kind of scientist are you, and what do you do?
Since I am a junior in college, I am still figuring out what my role is within the scientific community. I love to read and write, and I aspire to be a science communicator, but I’m still figuring out what role best fits me. What I do know is there is a distinctive difference between an intelligent person and a good teacher, and I want to teach others about science in an engaging way. 

One of my favorite things about being a scientist is seeing so many cool rocks and learning their stories! I’ve been collecting rocks and fossils since I was seven or eight years old! I enjoy showing others what fossils I have bought or found and telling the stories that accompany them. I also love public speaking and can see myself being successful in either an in-person capacity or creating videos/content online. I also think being a tour guide or research scientist for a National Park would be awesome! I am looking forward to exploring my options as I continue my education. 

What is your favorite part about being a scientist, and how did you get interested in science?
My beginning journey into the scientific community is a little bit unusual. I was first introduced to fossils in a Worldview, Logic, and Apologetics class (which is about advocating for the Christian Faith). I worked on an extensive project that asked the students to study a field of science of their choice in order to find evidence in support of the Christian faith. It was a very intriguing and motivating project that has led me down a now six-year philosophical and scientific journey to figure out how these two pieces of my life, religion and science, can coexist. Because of this class, I wanted to be a geologist because I wanted to know as much about our origins as humans, but also what has happened to our planet in geologic time. I also want to know how to learn from nature about our history, but also what we can do to maximize our future. 

I grew up with a stigma that in order to be a scientist, you needed to be an expert in math, lab activities, and memorization. I grew up attending a college prep school where STEM majors usually were pre-med or engineer inclined. I knew I was not interested in studying those fields (even though they are awesome in their own right!), and felt it was hard to keep up with kids in my classes because my focus was different.  It was a very competitive environment, especially because I lacked confidence in my ability in the skills I thought were necessary. However, after learning what geology was about in college, I knew I had found my place. Geology integrated my love for weird creatures, writing, and being outside! Combined with my natural inclination to write, I quickly fell in love with the idea of becoming a science communicator.

oung woman wearing a blue shirt and denim skinny jeans sits in a navy blue wooden lawn chair. She sits in front of a college campus with a hill in the background. The building behind her, on top of the stairs which climb the hill, is an old academic building with dolomite (a hard, sand-colored mineral) walls and arched windows.How does your work contribute to the betterment of society in general?
I once had a classmate tell me he used to be interested in paleontology, but they thought it was a “dead” science and became readily disinterested. The more I delved into the literature, the more I knew he was far from the truth! My goal as a scientist  is to advocate for the amazing things we can learn about our world through science (but especially paleontology!), and to hopefully encourage aspiring scientists that they can find their place in the scientific community. One way I have begun to do so is by starting my blog called Perusing the Primeval. My blog currently has a Book Review Section that includes the latest books in science communication. I have a review template that shares how technical the book is to help the reader get a sense for who the book’s intended audience is. There are a wide variety of books available, and my goal is to help someone looking for new recommendations to find something they will enjoy. I am currently working on a Species Spotlight section that will highlight a certain extinct species represented in the fossil record.

What advice do you have for up and coming scientists?
As I said before, I grew up in a competitive academic environment. I often felt like I was in academic “no man’s land”; I was bored in regular classes, but I was crawling to keep up in the advanced classes. I enjoyed school and wanted to challenge myself, so I was often comparing myself to kids who were more academically inclined in subjects that did not come naturally to me. I felt like I needed to compete against them in order to get a spot in a good college. Rather than focus on my strengths when applying to colleges, I pushed myself to do things I didn’t really like because I thought I needed to compete for my spot. I thought “being amazing at everything” was my ticket to a good school, but I found out very quickly that wasn’t true. If you are interested in going to college (or trade school or an apprenticeship), I would encourage you to lean on your strengths. If you have strong passions or interests, fuel the fire! Continue to hone in on those skills. If you aren’t quite sure of what you want, try different things and see what you like – but maybe not all at once. Your physical and mental health will thank you. If we as individuals were all “amazing” at everything, we wouldn’t need each other!