Earlier this year, a new study was published with a groundbreaking discovery from the John Day Fossil Beds Monument in central and eastern Oregon. While the park is mostly known for what are commonly called body fossils, things like teeth or bones, this discovery was different.
Conner Bennett led the team that uncovered the fossilized footprints of prehistoric birds, lizards, and mammals, which were published in the academic journal Paleontologia Electronica. He spoke with OPB’s “All Things Considered” host Crystal Ligori, explaining that 3D technology was crucial to the findings.
The following transcript has been edited for clarity and length.
Fossilized feliform tracks discovered at the John Day Fossil Beds National Monument in Oregon. This collection of trace fossils are between 29 to 50 million years old and give additional context to behavior of prehistoric birds, invertebrates, lizards, and mammals.
Conner Bennett et al. / Courtesy of the National Park Service
Crystal Ligori: Let’s just get right to it. Tell us what you found?
Conner Bennett: What we found are a variety of different fossil tracks. They are quite a bit different from body fossils, what we think of like big dinosaur skeletons, things like that. Body fossils tell us a lot about the structure of an organism, but a trace fossil is something like a track or a burrow, and it tells us a lot about behaviors.
What we ended up finding were the tracks from a lizard, a shore bird — something kind of like a plover — as well as something close to like a tapir or a rhinoceros. As well as some feliform tracks, this would have been something close to the size of something like Hoplophoneus, a smaller false saber-tooth cat.
Ligori: I understand some of the tracks date back 50 million years. Can you tell us more about the animals that made them?
Bennett: So, the 50-million-year-old tracks are from the Eocene, this is a really cool time period, and we get the tracks from lizards that we found as well as the beak impressions from this bird, which tell us a lot about how it was feeding. The rhinoceros or tapir, we’re not quite sure which, is actually from a little bit earlier, about 30 to 26 million years old.
Ligori: There have been body fossils discovered at the John Day Fossil Beds, but this is the first time that folks have been researching the tracks and imprints there, right?
Bennett: Yes, that is correct. This has been kind of an upcoming science for the past 30 or 40 years. Trace fossils have not really been the poster child, so to speak, of paleontology. Everyone gets [into paleontology] seeing the big skeletons and things like that and it’s really easy to overlook these burrows or these tracks, but trace fossils are a great accent to a body fossil.
I think this paper does a great job of attributing what we’ve learned from the body fossils–the skeletons and the bones — to the environment. We know what’s walking around, how they’re walking around, what feeding strategies they have, different things like that.
Trace fossils are really key in helping us to better understand just how organisms are interacting with the substrate and with their environment over time.
Digital elevation models show the fossilized footprints of a false saber-toothed cat discovered at the John Day Fossil Beds National Monument in Oregon. The findings were published in 2025 in Palaeontologia Electronica.
Conner Bennett et al. / Courtesy of Palaeontologia Electronica
Ligori: Your team used advanced 3D imaging techniques as part of this work. Can you talk about that technology?
Bennett: So photogrammetry is a really revolutionary tool for fossil track researchers, that allows us to kind of blow up the scale of these things. So, if anyone’s read the paper, they’d know how small these little tracks are from the birds or the lizards. They’re very small.
Our photogrammetry is essentially taking all of these photos of these tracks, we put them into a software, and it generates a 3D model for us. So we can move the model around, we can blow it up to scale, which we might be able to do with a microscope, but the cool thing about this is that we can also get those color contours, these digital elevation models or DEMs, and they kind of give us a bit more contrast to look at.
That difference in elevation in that surface shows us those features really easily, so things very small, little worm burrows or these little beak impressions, or even the claws on these bird tracks, we’re getting all of those details.
Ligori: Can you describe a little bit what a place like this would have looked like when these creatures were alive?
Bennett: So these Eocene fossils from about 50 million years ago are really cool. They’re telling us a lot about a shallow lakeshore environment [and] the combination of all of these traces together really tell us a lot about what’s kind of walking around, and then the types of rocks that they’re being preserved in tells us about the substrate.
We have these really fine-grained shales, and so these things that are walking around and have little, very easy-to-miss features are getting preserved. There’s not turbid water, there’s not high energy, and so that’s not being swept away.
