dinosaurs in their time

July 3, 2024 by Kathleen

Storytime at the Museum

When: Daily from 11:00 a.m.–11:30 a.m.

Where: Carnegie Museum of Natural History

Tickets: Free with Museum Admission

Join us for Storytime at the Museum! Hear nature and science stories read by our Natural History Interpreters and get a chance to touch museum specimens. Stop by for one page, one book, or stay for the whole time. Meets in Discovery Basecamp. Registration is not required.

Storytime at the Museum will not occur on Saturday, June 13 or Friday, June 26–Sunday, June 28, 2026. We encourage you to join us for DinoFest (June 13) and Polar World Closing Weekend (June 26–June 28) instead.

Purchase museum admission in advance →

July 3, 2024 by Kathleen

Storytime at the Museum

When: Daily from 11:00 a.m.–11:30 a.m.

Where: Carnegie Museum of Natural History

Tickets: Free with Museum Admission

Purchase museum admission in advance →

July 3, 2024 by Kathleen

Storytime at the Museum

When: Daily from 11:00 a.m.–11:30 a.m.

Where: Carnegie Museum of Natural History

Tickets: Free with Museum Admission

Purchase museum admission in advance →

December 19, 2022 by Erin Southerland

Stepping Back in Time

by Suzanne Nuss

I grew up in the silent Canadian Arctic, so sounds switch me to alertness. Once alert, I pause to hear spoken words. During a recent late afternoon in Dinosaurs in Their Time, I focused on a sound that moved me to alertness until it became the voice of the museum’s Gallery Experience Presenter Shannon McGuinn saying, “I found a footprint.”

Because the exhibition hall was mostly empty of visitors, I had been standing near and contemplating the visually striking display of the holotype Tyrannosaurus rex fighting in a field of replica Cretaceous poppies against a cast of another T. rex skeleton, the fossil that since its discovery in 1997 has been known informally as Peck’s Rex. As a Natural History Interpreter, I have been walking these halls for more than six years, yet I had never noticed a footprint. “Hmm,” I thought. “Really?”

I followed Shannon. She pointed. There it was: faint but unmistakable, on the recreated ground surface of the exhibit base, the impressions of three digits resembling a gigantic bird footprint.

We both entertained the same thought: if there’s one track, could there be more? We trotted over behind Peck’s Rex and yes. A second footprint was visible, two feet behind and under the tail, as if the animal had been ambling along.

At this point, Dr. Matt Lamanna, the person most responsible for the scientific content of the now-15-year-old hall, walked by. Gurgling with excitement, we showed him the footprints. He was delighted by our find. “Yes. Two ‘Easter Eggs.’ When Dinosaurs in Their Time was built, we included many simulated footprints, sculpted on the basis of actual fossilized dinosaur tracks. I only wish I’d been able to add a few fake coprolites (fossil poop) too.”

We continued to hunt, with Matt now with us. Three toes again, much smaller. Now that we recognized the tracks as intentional creations, we wondered what animal tracks we might find. Our third discovery, pictured below, was a faux footprint of the bird-like oviraptorosaur Anzu wyliei.

Moving into the Jurassic portion of the exhibition, we stepped back in time, figuratively speaking, by more than 80 million years, and were dwarfed by huge, long-necked, plant-eating dinosaurs (sauropods). We also found very different-looking tracks, some of which were overlapping. Our questions multiplied: could tracks like this indicate that these enormous beasts walked in herds? Is it possible to match up the toes of the foot with the footprint? Was the wide, flat heel of sauropods important for weight distribution?

Those thoughts captivated me, mainly because I was introduced to D’Arcy Thompson’s book, On Growth and Form, when I studied biophysics at McGill University in Montreal. One section of the book was devoted entirely to demonstrating how the many kinds of tetrapods (four-limbed, backboned animals such as amphibians, reptiles, birds, and mammals) all had the same fundamental form: head, torso, and tail, with forelimbs attached at the shoulder girdle and hind limbs attached to the hip. I loved the accompanying images that stretched all the body parts to ‘morph’ one tetrapod into another. A more technical term for this concept is “homologous structures.” In the image below, a simple letter key is used to mark forelimb bones: (H) humerus, (R) radius, (U) ulna, (C) carpals, (MC) metacarpals, and (P) phalanges (the latter better known as finger and toe bones). The hind limbs match up in a similar way.

Drawing of human, horse, and bat limb skeletons side by side

I thought about what a human footprint looks like, and then a horse footprint, and even a bat footprint. Bears and humans walk with their heels on the ground (a stance known as plantigrade). Horses and giraffes walk on the very tips of their toes (unguligrade), whereas cats, dogs, and predatory dinosaurs such as Allosaurus and T. rex walked on their toes (digitigrade).

Returning to my original spot within the dinosaur exhibition, I was determined to take a closer look. Could I tell from the fossil evidence how the species on display walked? Was it possible to identify the femur, tibia, and fibula of each skeleton?

The colorful murals lining the walls of the exhibition helped. The depictions of each creature are based upon well-studied fossils and biomechanical modelling. I could start musing about how they walked and make a guess. Each guess became a test, which produced a working hypothesis. I have since discovered that the museum’s Bird Hall and Hall of North American Wildlife are also great places to think about feet, footprints, and the biomechanics of animal movement, and why some dinosaur footprints look so much like bird footprints.

Footprints have stories to tell about movement, behavior, and speed. Properly interpreted, footprints can reveal how long their makers’ legs might have been, the width of these animals’ hips, and even whether adults and young traveled together in family groups. What, I have been steadily wondering, would the footprints recording a fight look like?

I don’t want to look anything up yet. I need to muddle through with my own thinking first. When I am ready, I might start with legged robot studies to clarify the physical constraints that must be considered in moving through space. I have since found simulated tracks of Allosaurus and Stegosaurus, and in my searching have also discovered how even an exhibition I know well still holds tremendous potential for inquiry and further learning.

Suzanne Nuss is a Natural History Interpreter at Carnegie Museum of Natural History.

Jurassic Days: Icarosaurus

by Zach Lyons-Weiler

View of Dinosaurs in Their Time exhibition from above — Image credit: Joshua Franzos, Treehouse Media

Both visitors and staff love Carnegie Museum of Natural History’s Dinosaurs in Their Time exhibition for many reasons. For some people, it is the huge dinosaurs such as Tyrannosaurus and Diplodocus that capture the imagination. For others, it is the Quetzalcoatlus that soars above the latest Cretaceous display, or the cute Psittacosaurus with its strange tail ornamentation. But for me, my favorite specimen is a rather obscure fossil replica hidden in plain sight in the Triassic and Early Jurassic area of the hall. Its name is Icarosaurus, and it is quite possibly one of the strangest animals that we have on display. When one first sees it, it looks like a cast of a jumble of bones on a background of dark shale. However, as you will come to realize, Icarosaurus is far more than just that!

The Carnegie Museum’s Icarosaurus (which is a high-quality replica of the only known original fossil) is displayed in a glass case alongside many other casts and fossils from what is known as the Newark Supergroup, a large deposit of rocks that snake their way from South Carolina to New Brunswick and Nova Scotia. These rocks were deposited during the Triassic and early Jurassic periods, or from roughly 230 to 190 million years ago. The sedimentary rocks here are intermittently intruded by younger volcanic rocks, indicating that this area was undergoing tremendous geological change at this time. During the Triassic and Early Jurassic, the supercontinent Pangaea was in the process of splitting up. The eastern coast of North America was rifting from western Africa, opening a furrow that would become the Atlantic Ocean. Before it was ocean, though, the rift was filled with lakes that were similar to Lake Victoria and Lake Tanganyika in today’s Great Rift Valley in Africa. The climate was warmer, too, and so the environment was wet and tropical. Due to climatic changes and natural oscillations in Earth’s orbit, these ancient rift environments would go through stages, from deep lakes to mudflats. Each layer preserved the remains of life that lived during that specific interval. Layers of rock deposited in deep lakes often contain abundant fossils of fishes, invertebrates, and reptiles. Other layers preserve footprints of early dinosaurs and other animals. Still others preserve the remains of cynodonts, which were the forerunners of mammals.

Dating to the late Triassic Period, the remains of Icarosaurus were discovered in one of the deep lake deposits by three teenagers in a quarry near North Bergen, New Jersey, which is just outside New York City. Upon discovering the fossil, they realized its importance and donated it to New York’s American Museum of Natural History, where it was named in 1966 as Icarosaurus siefkeri. This is, to this day, the only known specimen of this reptile, so it is of tremendous scientific value. Other lizard-like reptiles had been found in these deposits, but what made Icarosaurus so unique were the extremely long and unusual ribs that extended from its body. These ribs are similar in form to those of lizards in the extant genus Draco, which have elongated ribs connected by membranes of skin that they extend to glide between trees in their Southeast Asian rainforest homes. Because the rib anatomy of this modern group is so similar to that of Icarosaurus, scientists reasoned that the latter would have glided between trees in a comparable manner.

Icarosaurus was not the first reptile to have evolved this trait, though. During the Permian Period, around 260 million years ago, reptiles such as Coelurosauravus had adapted to a gliding lifestyle. Other extinct reptiles that evolved gliding morphologies include Mecistotrachelos from the Triassic of Virginia and Xianglong from the Cretaceous of China. The extreme similarity between these distantly related reptile groups is a remarkable example of convergent evolution, which is a process where organisms evolve the same traits due to their populations facing similar selective pressures. Other examples of convergent evolution that can be seen in the Triassic and Early Jurassic exhibits in Dinosaurs in Their Time are the phytosaurs Redondasaurus and Rutiodon, which resemble their distant relatives, crocodiles, and ichthyosaurs such as Ichthyosaurus and Stenopterygius, which bear an uncanny resemblance to dolphins.

The high school students that discovered Icarosaurus were lauded for their donation, and the discovery of such an odd animal made headlines in both the local and national news. Unfortunately, though, the fame and unique nature of the fossil caused some issues. The man for whom Icarosaurus siefkeri was named, Alfred Siefker, repossessed the fossil to put it in his personal collection in 1989. It stayed there until 2000, when he tried to sell it at auction. Understandably, the scientific community was upset with this decision, because if the fossil were to be sold into a private collection then it would be unavailable for scientific study. It was bought at the auction for well under its appraised value, and the buyer, Dick Spight, donated it back to the American Museum that same year. The original Icarosaurus specimen is currently on display at that venerable New York institution.

Overall, Icarosaurus is a remarkable little animal that deserves more attention than it gets. Look for it and other unique prehistoric animals the next time you visit the Dinosaurs in Their Time exhibition.

Zach Lyons-Weiler is a Gallery Experience Presenter in CMNH’s Life Long Learning Department. Museum staff, volunteers, and interns are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

What Did Dinosaurs Sound Like?

A Brief Foray into Paleoacoustics in Science and Film

by Niko Borish and Caroline Lee

Did Dinosaurs Roar?

When you think about dinosaurs as living animals, what do you think of? Many people imagine them as they are depicted in the Jurassic Park films – giant reptiles, clad in scales, generating reverberating roars that shake the screen. Although this image is certainly entertaining, research in recent years points to unexpected findings that are no less interesting. Evidence suggests that dinosaur vocalizations were not likely to have sounded like roars at all! We’ll explore what’s known about the real voices of dinosaurs with a paleontological source and an interview with an expert who has made relevant discoveries. We’ll also discuss how the sounds you hear in the Jurassic Park films were created!

Paleoacoustics and Dinosaur Vocalizations

We had a chance to interview Dr. Julia Clarke, a paleontologist at the University of Texas, to learn more about paleoacoustics (the study of sound associated with fossils) in non-avian dinosaurs and their evolutionary descendants, birds. In Antarctica in the mid-1990s, Vegavis iaai, an ancient bird dating to around 66 to 68 million years ago, was excavated. Dr. Clarke analyzed the fossil, and in 2013 found evidence that Vegavis had a vocal organ specific to birds, known as a syrinx. In extant (meaning alive today) bird species, the syrinx is responsible for all the vocalizations we identify as bird songs or calls. This means that Vegavis most likely honked (not unlike a goose), owing to an asymmetrical third segment in the syrinx. When we asked why it took about two decades to find the syrinx after the fossil’s original discovery, Dr. Clarke answered that “discovery is not just one moment.” She received the fossil for study in 2008. When she was about to return it in 2012, she went over its computed tomographic (CT) scan images again and noticed something new – a tiny structure that looked like a simple bone fragment or toe bone on the surface of the rock. It turned out to be the syrinx! Clarke and her coauthors noted that we still don’t know when the syrinx evolved because non-avian dinosaur fossils lack this structure. Vegavis is related to extant bird species, and despite searching, no earlier dinosaur syrinxes have so far been found.

Carnivorous dinosaurs are often pictured as chasing prey while letting out intimidating roars. Other new discoveries made from studies of extant birds indicate that this image is a misconception. Dr. Clarke explained that instead of open-mouthed roars, scientists theorize that many dinosaurs may have produced closed-mouth vocalizations. Animals produce closed-mouth vocalizations by inflating their esophagus (the tube that connects the throat and stomach) or tracheal pouches (pouches on their windpipe) while keeping their mouth closed, producing something comparable to a low-pitched swooshing, growling, or cooing sound. These closed-mouth vocalizations differ substantially from open-mouth vocalizations like bird calls. Think of closed-mouth vocalizations as being lower and more percussive, as opposed to bird calls, which are more varied in pitch and almost melodic. Modern examples of closed-mouth vocalizations include crocodilian growls and ostrich booms. As a result, scientists reasoned that many dinosaurs did not perform open-mouth vocalizations, but could have generated closed-mouth vocalizations instead. Although birds evolved from theropods (a group of dinosaurs characterized by, among other attributes, hollow bones and a bipedal stance), theropods likely did not have the ability to make complex sounds similar to those of extant songbirds.

Perhaps sadly, the exciting, blood-curdling roars in the Jurassic Park franchise are not scientifically accurate. Current evidence supports that Tyrannosaurus rex made closed-mouth vocalizations, but in the films, the Tyrannosaurus opens its mouth every time it roars. That begs the question: who or what voiced the Tyrannosaurus and other Jurassic Park dinosaurs? The majority of the sounds used to create the Tyrannosaurus sonic palette came from recordings of elephant bellows. Also used were crocodilian growls, roars from lions and tigers (but not bears), the sound of water coming up from a whale’s blowhole, and even growls from the sound producer’s dog. Some other animals’ sounds that were used to make different dinosaurs’ vocalizations include: hawing donkeys, neighing horses, growling tortoises, whistling dolphins, howling howler monkeys, oinking pigs, barking fennec foxes, and chirping birds! Most of these sounds were edited and pitched up or down to fit their roles.

Another popular misconception initiated by the Jurassic Park franchise was the concept of the “Velociraptor resonating chamber.” In Jurassic Park III, the protagonists search for a “Velociraptor resonating chamber” that allows them to communicate with the Velociraptor pack. However, the possibility of this structure was debunked by Dr. Clarke and Dr. Matt Lamanna, a paleontologist at Carnegie Museum of Natural History. The resonating chamber does not actually exist. If such a chamber existed, it would only amplify the sound (auditory vibrations that travel through the air) made by dinosaurs, not modify its timbre (the tone quality of a sound) or pitch (a measure of how high or low a sound is), which would not allow humans to imitate Velociraptor sounds as shown in the movie. In other words, it would not work like a giant duck call. Additionally, the way that scientists perceive closed-mouth vocalizations to function disproves the whole idea of a resonating chamber to begin with. This is because the organs involved in vocalization include either esophageal or tracheal pouches but no dedicated “resonating chamber.”

What non-avian dinosaurs really sounded like is an enigma currently being uncovered by teams of researchers like that led by Dr. Clarke. All in all, while the movies are certainly helpful for getting people interested in dinosaurs and paleontology, a logical next step is to schedule a visit to Carnegie Museum of Natural History to get the real facts!

We would like to extend a gargantuan thank-you to Dr. Julia Clarke and Dr. Matt Lamanna for generously offering expertise for our blog! Their help evolved our blog to the next level, and for that we are extremely grateful.

Niko Borish and Caroline Lee are Teen Volunteers in the Education Department. Museum employees, volunteers, and interns are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

References

Analysis of fossilized Antarctic bird’s ‘voice box’ suggests dinosaurs couldn’t sing. (2016, October 12). National Science Foundation. Retrieved March 7, 2021, from https://www.nsf.gov/news/news_summ.jsp?cntn_id=189996

Clarke, J. (2016, July 16). New Research Debunks The Dinosaur’s Roar (Interview by L. Wertheimer) [Radio broadcast]. In Weekend Edition Saturday. National Public Radio. https://www.npr.org/2016/07/16/486279631/new-research-debunks-the-dinosaurs-roar

Riede, T., Eliason, C. M., Miller, E. H., Goller, F., & Clarke, J. A. (2016). Coos, booms, and hoots: The evolution of closed-mouth vocal behavior in birds. Evolution, 1734-1746. https://doi.org/10.1111/evo.12988

Taylor, D. (Host), & Nelson, A., & Clarke, J. (n.d.). Tyrannosaurus FX (No. 105) [Audio podcast episode]. In L. Battison (Producer), Twenty Thousand Hertz. Twenty Thousand Hertz. https://www.20k.org/episodes/tyrannosaurusfx

Storytime at the Museum

Storytime at the Museum

Storytime at the Museum

Stepping Back in Time

by Suzanne Nuss

Related Content

Carnegie Museum of Natural History Blog Citation Information

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Jurassic Days: Icarosaurus

by Zach Lyons-Weiler

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Carnegie Museum of Natural History Blog Citation Information

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Share this post!

What Did Dinosaurs Sound Like?

A Brief Foray into Paleoacoustics in Science and Film

Did Dinosaurs Roar?

Paleoacoustics and Dinosaur Vocalizations

Related Content

Carnegie Museum of Natural History Blog Citation Information

Share this post!

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