DINOSAURS UNDER THE BIG SKY
Written in Summer 2007/Updated Annually
NOTE: Large sections of this information on paleontology, geologic time, scientific methods, geology and dinosaurs of Montana, and museum exhibits have been taken directly from Jack Horner’s book, Dinosaurs Under The Big Sky, and from the Museum of the Rockies’ (MOR) exhibit materials. This information has been compiled, summarized, and edited for internal use by MOR’s staff, docents, and other volunteers. Any external use of this information requires the permission of the author (book) or MOR (exhibit materials). Attempts have been made to reference sources to give proper credit and to assist readers in finding the original material to “read more about it!” Credit to Dinosaurs Under The Big Sky appears as DBS followed by a page number, e.g. DBS, p. 1.
DINOSAURS AND GEOLOGIC TIME
Paleontology combines geology and biology to study extinct organisms preserved in rocks. Knowledge of geology helps scientists know where to look, what to look for, and how old the fossils are. Geological information helps paleontologists figure out what happened to animals, what may have killed them, and what happened to their remains after they died (DBS, p. 16).
Geologic time is 4.5 billion years of the earth’s history that is represented by and recorded in layers of rock. Over the course of geologic time, the continents have moved and shifted, and sea levels have risen and fallen. The geological rock record spans over 4 billion years. Scientists developed the geological time scale to help keep track of where fossils are found within this rock record. The scale uses units of time called eons, eras, periods, epochs, and stages. The scale includes four eras: Pre-Cambrian, Paleozoic
, Mesozoic, and Cenozoic. Dinosaurs existed for 155 million years during the Mesozoic Era and were the dominant animal longer than any other type that has ever lived (DBS, p. 16).
NOTE: When reading this narrative, the exhibit materials, and other resource material, the reader will note different dates have been assigned to the geologic units of time. The geological time scale is so immense that estimated time frames may vary by several million years in different sources. A good geological time scale reference chart can be found in the book, Dinosaurs Under The Big Sky
, p. 17.
GEOGRAPHY OF THE WORLD DURING THE MESOZOIC ERA
The Mesozoic Era lasted for 165* million years, during which time the earth underwent considerable change. The Mesozoic Era is divided into three time periods called the Triassic,
Jurassic, and Cretaceous Periods. During the Triassic Period, all the continents were joined together to form a super continent referred to as Pangea. Some of the evidence for this super
continent comes from fossil animals. There are reptiles, for example, that come from Triassic Period rocks of North America that are identical to reptiles found in Triassic Period rocks of Europe and Africa. Geologic studies indicate that Pangea began to break up into today’s continents near the end of the Triassic Period.
During the Jurassic Period, the continents were separating and the Atlantic Ocean was beginning to form, but there were still several large land bridges between many of the continents. As a result, many of the dinosaurs of the Jurassic Period are similar in some parts of the world.
By the Cretaceous Period most of the continents had separated and all of the oceans had formed. Only a few small land bridges remained. By the end of the Cretaceous Period, the continents were in much the same location as they are today.
*In some cases, certain dates and descriptions from Jack Horner’s book, Dinosaurs Under the Big Sky, disagree with panel text from the exhibit, Dinosaurs Under the Big Sky. Where they disagree, we have chosen to select one or the other on a case-by-case basis.
Montana is famous for its dinosaurs because of the lucky juxtaposition of geology and time. Montana has the right kinds of rock units containing dinosaur fossils and the right amount of time and erosion has taken place to bring the fossils to the surface.
Dinosaur remains are common in Montana and the Province of Alberta in Canada because rock from the Mesozoic Era, the age of dinosaurs, now sit at the surface, where wind and rain can erode it. In other places, most of the Mesozoic rock is still buried under thousands of feet of younger rock. In some other places, the Mesozoic rock eroded away a long time ago.
Although dinosaur skeletons are found in Montana, the skeletons of modern animals are rarely found. Skeletons can only be preserved if sediments cover them before they rot away. Prairies and badlands are areas of erosion rather than deposition. When dinosaurs lived in Montana, they lived in areas of deposition where skeletons could be covered by sediments laid down by streams, rivers, lakes, seaways, or wind. On the prairie, there is no way for sediments to bury a carcass. There are no prairie environments preserved in the fossil record (DBS, p. 19).
People have collected dinosaur fossils in Montana for over 150 years. The first dinosaur remains found in North America came from the mouth of the Judith River in what is now central Montana. Ferdinand Hayden, a geologist doing a geological survey of the American west, stopped off at Fort Claggett near Judith Landing in 1855. While out looking at the geology, he picked up several small teeth which he took back to Philadelphia and gave to Joseph Leidy, one of America’s first paleontologists. Joseph Leidy examined each of the teeth, and determined that they belonged to a variety of dinosaurs. He gave new names to the teeth including Deinodon, Troodon, Trachodon, and Palaeoscincus.
Paleontologists, museums, universities and academic institutes, commercial “fossil hunters” and amateur collectors continue to explore Montana’s dinosaur “roots.” Some of the most significant fossil discoveries have been made by people who were not on a “dig.” Ranchers, farmers, hikers, hunters, and people just walking around have made exciting dinosaur discoveries. Collecting dinosaur fossils on public lands requires a permit and collected items are stored in national repositories such as the Museum of the Rockies (DBS, p. 4)
Some of Montana’s more famous dinosaur discovery “firsts” include:
(DBS, p. 2):
First dinosaur remains found in the Western Hemisphere came from near the mouth of the Judith River in central Montana
First dinosaur eggshell reported from the Western Hemisphere came from Montana
First nest of baby dinosaurs found in the world
World’s first dinosaur embryos
Remains of the following dinosaurs were first found in Montana:
Tyrannosaurus, Maiasaura, Deinonychus, Troodon, Orodromeus,
Tenontosaurus, Einiosaurus, Ankylosaurus, Avaceratops
, and many more
DINOSAURS AND THE MUSEUM OF THE ROCKIES
Museums save and protect fossils for future generations. Research-based museums, like the Museum of the Rockies, collect fossils primarily to learn new information about extinct creatures and to display this information so people can learn about the past (DBS, p. 8). The Museum of the Rockies is a leading paleontology research institution. The Paleontology Department hosts several world-class research laboratories where cutting-edge science is happening every day. PhD, graduate
, and undergraduate students have access to research facilities second to none. The museum’s research facilities include five laboratories and one of the largest paleontology field programs in the United States.
In the Fossil Preparation Laboratory, skilled preparators take fossils from the plaster field jackets, remove earth and rock from around the fossil, and prepare the fossil for study or display. Preparators use dental picks, scrapers, grinders, and engravers to remove debris from fossils. Some fossils even require the use of sand-blasters or have to be dipped in acid baths. The Fossil Viewing Laboratory is located at the entrance to the Siebel Dinosaur Complex. Visitors can watch or “view” volunteer preparators working on fossil specimens still within their plaster jackets.
The MOR Histology Lab is the only one in the United States with a staff dedicated full-time to the preparation of thin-section slides of fossil specimens. Paleohistology is the study of the microscopic internal structure of fossil specimens. Thin-section slides are used to study fossilized bone, ossified tendons, eggshells
, teeth, and coprolites (fossilized dung). Modern (extant) animal bones are also sectioned for comparative analysis.
Gabriel Laboratory for Cellular and Molecular Paleontology:
In this laboratory, bones are analyzed at the cellular and molecular levels. Chemical analyses provide means to search for biomolecules such as proteins. Histologic slides are studied to reveal information about dinosaur physiology, growth, health, reproduction, and biomechanics. Polarized and fluorescent light microscopes are used for study of thin-sections. Digital photomicrographs are produced and investigated with image analysis (IA). Full specimens can be imaged with a cabinet X-ray machine, and specimen samples as well as thin-section slides can be analyzed with a scanning electron microscope (SEM).
Paleo-Technology is both a laboratory and a program where information is developed to analyze form, function, and spatial relationships of everything from dinosaur bones and skeletons to geological outcrops. Using X-rays and a variety of 3-Dimensional scanners, the museum has the capability of analyzing specimens as small as individual teeth or as large as the MOR building. Computerized tomographic scans (CAT-Scans), taken at Bozeman Deaconess Hospital, are processed with special software and the data used to better understand dinosaur bone structure
, brain size, hearing, and sound production. Surface scanning, coupled with known fossilized footprints, aids in the reproduction of 3D models to illustrate how dinosaurs might have walked or run. The LIDAR (Light Detection and Ranging) system is used to map skeletons in the field or entire outcrops so precise measurements can be made of skeletal arrangements and sediment layers.
MOR Paleontology Field Program:
The museum operates one of the largest paleontology field programs in the United States and is equipped to support several fully functional field camps. Large equipment includes heavy duty trucks, ATVs, equipment trailers, cook trailers, and boats. The museum has also maintained research bases near Rudyard, Montana, and Choteau, Montana, where paleontology research and education programs are conducted by museum staff and volunteers, MSU faculty and students
, and visiting scientists.
Fossil Collection: T
he museum’s dinosaur fossil collection has expanded from three specimens in 1982 to over 35,000 specimens. Research using dinosaur fossils has resulted in significant discoveries and the development of hypotheses or ideas about the relationship between dinosaurs and birds; dinosaur social behavior; dinosaur physiology; dinosaur extinction; and ideas about what dinosaurs ate, where they nested, and how they evolved.
Key reasons the Museum of the Rockies is famous for its dinosaurs include:
Largest collection of North American dinosaur fossil specimens in the United States (over 35,000 specimens).
National repository for dinosaur fossils found on public lands.
World-class paleontology research by paleontology staff, museum research associates,
MSU undergraduates and graduate students, post-doctoral candidates, and volunteers.
One of the first histology laboratories in the world fully devoted to dinosaur fossil
Led multi-year investigation of the Hell Creek Formation by paleontologists,
paleogeologists, paleobotanists, and other scientists from around the world.
One of the largest paleontology field programs in the United States
Key dinosaur discoveries by Museum of the Rockies paleontologists and associated research teams:
(DBS, p. 195)
First dinosaur eggs in the Western Hemisphere
First evidence of nesting colonies and parental care among dinosaurs
First dinosaur embryos
Flexible soft tissue found in fossilized bone.
Medullary bone found only in egg-laying birds was found in “Catherine”
(B-rex ) indicating this T-rex was an ovulating female.
First evidence of a dinosaur that dug burrows
TRAVELING DINOSAUR EXHIBITS:
The Museum has developed several very successful traveling exhibitions showcasing dinosaur fossil specimens and research. An exhibit called Dinosaur Babies
(1990-2002) showcased Maiasaura
discoveries and research on growth and behavior including parental care. T-rex on Trial
(1998-2003) focused on research to determine whether T-rex
was a predator or a scavenger. In July, 2011, the newest traveling exhibit. Growth and Behavior of Dinosaurs,
debuted in Japan to rave reviews and received wide acclaim in other Asian venues over the next three years. This exhibit highlights the museum’s research on the maturation of dinosaurs from juveniles to adults.
THE SIEBEL DINOSAUR COMPLEX
This complex is a series of halls showcasing research by Jack Horner and his research team and bringing the treasures of the museum’s collection up, out of the basement, and onto the floor. Visitors will find thousands of actual fossils—many of which cannot be seen anywhere else in the world—in over 10,000 square feet of display space. What makes this exhibition unique, beyond the astonishing numbers of dinosaur fossils, is its interpretive approach.
This data-rich exhibit engages visitors in the science of paleontology: how we know what we think we know about dinosaurs. At every turn they encounter the latest research on life in the Mesozoic Era, abundantly evident in Montana
, as well as the processes of research. Visitors are challenged to formulate their own hypotheses about dinosaur growth, development, behavior and interactions with their environments. As new discoveries and scientific breakthroughs are made, visitors will see changes in the exhibit.
The Siebel Dinosaur Complex houses the Dinosaurs Under The Big Sky
exhibit which is one of the largest and most up-to-date dinosaur exhibits in the world. The complex includes three halls:
The Hall of Giants
opened June 2007: This hall features Late Jurassic dinosaurs (Allosaurus
; Early Cretaceous dinosaurs (Tenontosaurus
); and a Middle Cretaceous dinosaur (Oryctodromeus
) and maritime plesiosaurs. A fossil viewing lab where visitors can watch fossil preparation is located at the entrance to the Siebel Dinosaur Complex. .
The Mesozoic Media Center and The Hallway of Growth and Behavior
opened Summer 2006. This area contains both a media center and interactive computer stations. The hallway includes fossil cases featuring dinosaur eggs and skulls and Late Cretaceous dinosaur fossils including Maiasaura, Troodon, Daspletosaurus, Hypacrosaurus, Brachylophosaurus
, and Saurornitholestes.
The Hall of Horns and Teeth
opened June 2005. This hall contains Latest Cretaceous dinosaur fossils and features Hell Creek Formation dinosaurs including Tyrannosaurus, Triceratops
DINOSAURS UNDER THE BIG SKY EXHIBIT
The Museum of the Rockies is a museum of science. The most important component of science is physical evidence. Paleontologists use dinosaur fossils as the physical evidence to develop hypotheses and theories about dinosaur physiology, growth, behavior, adaptation, death, and environment. The museum has over 35,000 dinosaur specimens in its collection, the largest collection of North American dinosaur fossils in the United States. We have put some of the museum’s most treasured and rarest dinosaur fossils on display within this exhibit.
The exhibit represents the cutting-edge of dinosaur science. Dinosaur paleontologists use science to develop hypotheses and theories about dinosaurs. Then, they write papers about their studies and submit them for publication in scientific journals. Other paleontologists (peers) scrutinize and review these papers to be sure they are scientifically sound. If the science is determined to be sound, interesting, and important
, the papers are published. The science presented in this exhibit has been subjected to this kind of scientific peer review. To document
the scientific research presented in this exhibit, published scientific papers are cited on exhibit panels.
The Hall of Giants contains several life-size, fleshed out models (e.g. Deinonychus
attacking Tenontosaurus; Edgarosaurus
plesiosaur). In science, what we know is derived from physical evidence. What we know about dinosaurs is derived from dinosaur fossils. Fossil skeletons are the primary physical evidence used to develop likely size, shape, stance, muscles, skin texture, etc for the models. The models and the vegetation are based on the most current research and fossil material, combining the expertise of paleontologists, paleobiologists
, biologists, and artists to produce convincing and realistic models.
The exhibit is designed to get people to think because science is about discovery. The exhibit provides numerous discovery opportunities for visitors by posing questions, presenting fossil evidence, and allowing visitors to develop their own answers. Some “Discovery Opportunity
” points are highlighted in exhibit descriptions for possible use by docents.
The exhibit walls are intentionally painted black to encourage visitors to use their imaginations: to see the fossil evidence; to listen to the sounds; to look back in time to the Mesozoic Era, the time of dinosaurs. The sound tracks were created by slowing down modern animal sounds (e.g. elephant and bird sounds).
In the Dinosaurs Under the Big Sky
exhibit, visitors are invited to learn about science and 90 million years of our planet’s history, all interpreted through dinosaur remains found in Montana. The Museum of the Rockies is a research museum and is part of Montana State University. This world-class exhibit is “Montana-grown,” too. Almost all of the research featured in the exhibit was conducted by MSU students, staff, and research associates working at the museum. Approximately 99% of the dinosaurs in the exhibit are from Montana as are the craftsmen, sculptors, and artists who worked on the exhibit.
Throughout the Dinosaurs Under The Big Sky
exhibit, visitors will encounter five key themes:
Paleontologists use the scientific process, including physical evidence (e.g. fossils) to develop scientific theories about dinosaurs.
Different dinosaurs lived at different times in the Mesozoic Era.
Fossil evidence can tell us about dinosaur growth and behavior.
Dinosaurs are the ancestors of birds.
The science presented within the Dinosaurs under the Big Sky exhibit was accomplished by students, former students and staff of Montana State University
Visitors face the Fossil Viewing Laboratory as they approach the entrance to the Dinosaurs Under The Big Sky exhibit. Through floor-to-ceiling windows, visitors can watch volunteer preparators work on plaster-jacketed dinosaur fossil specimens.
As visitors enter the exhibit, they see a hallway of panels that introduce them to the scientific process, the field of paleontology, the fossilization process, and answers to common questions about dinosaurs and where we find dinosaur fossils.
Panel: HOW DO SCIENTISTS KNOW WHAT WE THINK WE KNOW?
Scientists gather physical evidence and observe and compare which enables them to learn new information. Physical evidence is the single most important component of science. Science without physical evidence is opinion, and opinion is not science—even if it’s the opinion of a scientist!
Panel: WHAT IS A HYPOTHESIS?
A hypothesis is a scientific idea supported by physical evidence. Scientists gather and observe physical evidence. Then, they propose an idea based on that physical evidence. This idea is called a hypothesis. Hypotheses (more than one hypothesis) may be true or they may be untrue; but it takes physical evidence to propose them and to disprove them.
Although scientists do gather physical evidence to support their hypotheses, good scientists look for evidence that their hypotheses are wrong, instead of right. This may seem strange, but instead of trying to figure out whether their ideas are right, scientists try—and invite others to try—to prove that their hypotheses are wrong. The more times a hypothesis is tested and not disproved, the stronger it becomes. This is how scientific knowledge advances—we learn from our mistakes and keep trying to improve our understanding based on the evidence we find. A hypothesis must be testable, either by repeating or falsifying (disproving). A chemist might repeat an experiment, but a paleontologist cannot repeat long-past events. The very best hypotheses in paleontology are those that can potentially be disproved.