The WitmerLab has an ongoing collaboration on the duckbilled hadrosaur dinosaurs with David Evans of the Royal Ontario Museum in Toronto. Recently, we’ve received word that some of that work has found its way into the “Dinosaurs Unearthed” exhibit that has been circulating through the US. First, Ohio University grad student Haley O’Brien texted me a photo of the exhibit at Union Station in Kansas City, and then Texas Tech grad student Rissa Westerfield posted a photo on Facebook of the exhibit at the Museum of Nature & Science in Dallas. Then just yesterday, WitmerLab alum Casey Holliday (now at Missouri) chimed in with his own sighting in KC. Presumably, it’s elsewhere, too. We’re thrilled to hear that the outcome of our research is reaching a broad audience!
Our corner of the Dinosaurs Unearthed exhibit relates to our work on the complicated nasal cavities, brains, and ears of lambeosaurine hadrosaurs. I haven’t seen the exhibit and wasn’t involved in it in any way, but the basic idea seems to be based on our finding, corroborating the work of others, that that the nasal cavity, with all of its loops and chambers, formed a vocal resonating chamber within the bony crests atop the heads of lambeosaurs like Corythosaurus, potentially helping to generate low-frequency sounds. Moreover, we found that the elongate hearing organ of the inner ear (the cochlea) was probably “tuned” to hear such deep calls…and that tidbit also found its way into the exhibit. The exhibit is a multimedia affair, apparently drawing on visualizations that we put together in 2008 as part of the press conference at the annual meeting of the Society of Vertebrate Paleontology. I’m posting them here, too, including the YouTube version of the video below. The exhibit also includes the sounds that some of these hadrosaurs may have made, as modeled on the resonant properties of the hollow nasal crest of the related lambeosaur Parasaurolophus by researchers in New Mexico in 1998.
In 2009, David Evans, Ryan Ridgely, and I published this study, which has more analytically advanced versions of the visualizations, as well as some pretty detailed analyses of the functional implications for what we found. We had juveniles in our study, as also shown in the exhibit, and so we were able to shed light on how these structures changed as these animals grew. The pipsqueaks (literally!) would have had somewhat higher pitched voices that deepened as they aged, like humans. We also addressed other potential functions of the crest, hopefully putting the final nail in the coffin of “the olfactory hypothesis” that argued that the crazy nasal crests of lambeosaurs enhanced the sense of smell. Another key finding is that the nasal convolutions almost certainly had a positive function (like vocal resonance) beyond just inflating the showy visual display ornament of the crest, in that some lambeosaurs, like Hypacrosaurus, show internal complexity that isn’t reflected externally. Put simply, these nasal crests weren’t just for show…they had other functions, such as creating species-specific—and maybe even individual-specific—vocal communication. Finally, our study of the brains of these beasts showed that the higher centers (cerebral hemispheres) were remarkably expanded, suggesting that they may have had the cognitive wherewithal to engage in maybe some pretty sophisticated social behaviors. The Dinosaurs Unearthed exhibit doesn’t present the full richness of the story, but it gives a nice taste of what the scientific study was all about. You can also read some of the press reports (e.g., NSF, Science, NatGeo, Discovery) on the 2008 media site, or read an award-winning blog post by Mo Costandi! And David, Ryan, and I aren’t done with hadrosaurs yet, so stay tuned for more!