Andrews Expedition Discovers the First Fossilized Dinosaur Eggs Summary

  • Last updated on November 10, 2022

The expeditions that led to the discovery of the first fossilized dinosaur eggs contributed to the progress of paleontology.

Summary of Event

The purpose of a series of expensive scientific expeditions to the Gobi Desert from 1921 to 1930 was to investigate Henry Fairfield Osborn’s theory that central Asia had been the site of the evolutionary origin of humans and other mammals. As president of the American Museum of Natural History in New York City, Osborn was in a position to promote the explorations. Although he believed that supporting hominid fossil evidence would be found, Osborn was interested also in building the museum’s collections. He especially promoted educational displays of taxidermy specimens, artifacts, and fossils found on expeditions. Dinosaurs Paleontology Fossils;dinosaur eggs [kw]Andrews Expedition Discovers the First Fossilized Dinosaur Eggs (1923) [kw]Expedition Discovers the First Fossilized Dinosaur Eggs, Andrews (1923) [kw]First Fossilized Dinosaur Eggs, Andrews Expedition Discovers the (1923) [kw]Fossilized Dinosaur Eggs, Andrews Expedition Discovers the First (1923) [kw]Dinosaur Eggs, Andrews Expedition Discovers the First Fossilized (1923) Dinosaurs Paleontology Fossils;dinosaur eggs [g]Mongolia;1923: Andrews Expedition Discovers the First Fossilized Dinosaur Eggs[05670] [c]Prehistory and ancient cultures;1923: Andrews Expedition Discovers the First Fossilized Dinosaur Eggs[05670] [c]Science and technology;1923: Andrews Expedition Discovers the First Fossilized Dinosaur Eggs[05670] Andrews, Roy Chapman Granger, Walter Osborn, Fairfield, Sr. Olsen, George

Launching the Central Asiatic Expeditions Central Asiatic Expeditions into the Gobi (the desert’s name means, literally, the “sandy waste”) was not a casual matter. Poor roads, great distances, few people, high winds, sandstorms, and severe climate were all factors to overcome. During the winter, the temperature was lower than –40 degrees Celsius. Because of these conditions, scientific work was limited to April through October. In addition, explorers might face conflicts with bandits, warlords, and local government officials. Food and gasoline had to be brought in by camel caravan. Fortunately, the water table in the Gobi is not deep, and occasional wells allowed caravan travel. Nevertheless, the services of an expert who could thoroughly plan and wisely lead the expeditions were required.

Roy Chapman Andrews, who had studied and collected whale specimens for the museum, was chosen to lead the expeditions. Andrews first thought of using airplanes, but the Chinese authorities would not give permission. He then chose to use motor vehicles—two Fulton one-ton trucks and three Dodge cars, all unmodified, to travel into the wilderness of the Gobi Desert. He believed that the vehicles would save time and thus increase the amount of exploration possible. Andrews’s plan also included 150 camels to bring in advance supplies to depots, and a staff of forty men was hired to support about fifteen scientists, experts from various fields. When discoveries were made, all enjoyed the interaction of scientists who were experts in geology, paleontology, zoology, topography, and botany.

Andrews also included J. B. Shackleford Shackleford, J. B. in the group to document discoveries with both still photographs and motion pictures. Shackleford did excellent work, but chance allowed him to play a larger role. During the first year in the field, he discovered an interesting fossil at a place the group had named Flaming Cliffs. He had wandered off to do some exploring while the others waited for word from a scout car, and at an outcropping of upper Cretaceous rock, he found a skull that was 20 centimeters (7.87 inches) long. Walter Granger, the expedition’s chief paleontologist, recognized the skull as that of an unknown dinosaur. The skull and some bits of eggshells that Granger found at the cliffs were sent to the museum.

When the specimens arrived in New York, William K. Gregory Gregory, William K. determined that the unknown dinosaur was a predecessor of the well-known three-horned American dinosaur Triceratops. This new Mongolian species, however, had yet to evolve its horns and was smaller. Gregory called it Protoceratops andrewsi and strongly suggested that the members of the expedition should find more specimens. They returned to Flaming Cliffs in 1923 and spent two months searching the area. Immediately on their arrival, they discovered more Protoceratops. The area was so rich that by the end of the first day, each worker was busy carefully applying glue and cloth to strengthen his own fragile specimen as it was removed.

On the second day, George Olsen reported that he was sure he had found fossil eggs. At first the others were incredulous, and they teased him. Then, however, they tried seriously to account for the eggs. No birds were known from the lower Cretaceous period. All the Jurassic and upper Cretaceous birds were much too small to have laid eggs of the size Olsen found. Birds’ eggs are usually ovate, a shape that prevents their rolling out of a nest; reptile eggs, which are buried in the ground, are usually elongate. The specimens were ovate. The fact that they were found in beds where only dinosaur fossils were discovered implied that they were dinosaur eggs. The researchers were finding more than one type of dinosaur fossil, but only one was large enough to lay the eggs. Therefore, they concluded, Protoceratops andrewsi must have laid the eggs.

Three of the eggs were in a cluster and evidently had remained in the exact spot where they had been deposited by the dinosaur. The broken shells of several others were partially embedded in the rock. Each egg was about the size and shape of a large baked potato, about 22 centimeters (8.66 inches) long. The shells were hard but wrinkled. Several eggs had been broken in half. In these, the scientists were sure they could detect the small bones of embryonic dinosaurs. Now there was no doubt that the eggs were from a dinosaur.

During the weeks of study at Flaming Cliffs, the scientists collected a complete developmental series of Protoceratops at all stages. Specimens included eggs, just-hatched youngsters, and juveniles of various ages through 3-meter (9.8-foot) adults. Olsen found a different birdlike dinosaur among the fossils and suspected it of being a predator. Because of the circumstances, the dinosaur was named Oviraptor philoceratops: “thief with love for ceratopsian eggs.”

Because the specimens were found at different levels, Andrews concluded that they were not all buried at the same time. The presence of so many fossils of the same species in one area indicated to him that the region must have been a feeding ground or perhaps a source of water. The area was a Protoceratops breeding ground. Andrews thought that perhaps the location had the right type of sand to provide the proper amounts of heat and air for incubation.

In the 1923 season, the expedition sent back several skeletons, more than fifty skulls of Protoceratops andrewsi, and fifty eggs, some still in nests. The scientists shipped sixty cases of fossils packed in handy camel hair with the belief that the Flaming Cliffs were still not exhausted. In 1925, an even larger group of researchers returned to the cliffs to find additional fossils. Olsen continued to find most of the eggs. One of his nests, which had eggs fastened to the underside of a rock, can be found in the Field Museum of Natural History in Chicago. Eggs of two smaller dinosaurs were found also during later visits. Most of these specimens were sent to the museum in New York.

In 1925, one of the expedition’s motor vehicle experts, Norman Lovell, Lovell, Norman happened upon the best Protoceratops nest. Interested in capturing a young eagle for a pet, he had approached a cliff with a 60-meter (197-foot) drop. Reaching over the side from the top, he scratched his hand on a sharp object that turned out to be a broken dinosaur eggshell that was part of a nest. He reported his find, and Granger removed the eggs while reaching over the cliff, braving high winds. A section of sandstone with the eggs in it, weighing half a metric ton, was removed and sent to the museum. The nest held eighteen eggs standing on end in an irregular circle. Originally, more eggs might have been in the nest, but parts had crumbled away with erosion of the cliff.

Expeditions returned to the Gobi in 1928 and 1930 to make other discoveries. Andrews, Granger, and Osborn published popular articles and books that described their adventures.


At the time when Andrews and his colleagues published the stories of their expeditions, people were just becoming accustomed to the idea of the dinosaurs. Fossils of the forgotten beasts were first found in the nineteenth century, and restorations created from the bones were still rare. The large eggs that the Gobi explorers found made dinosaurs seem more real to the public at large.

The amount of interest shown in the eggs surprised Andrews. He believed that the tiny skulls of the earliest known mammals that lived during the age of the dinosaurs were far more important scientifically. Also, his 1925 discovery of artifacts from ancient “dune dwellers” at Flaming Cliffs was more in line with the goals of the expedition. Moreover, there was the finding of the bones of the giant Baluchitherium, a type of rhinoceros. The 95-million-year-old dinosaur egg discovery had been a fortunate accident, and Andrews regarded it as important, but not to the extent the public perceived it to be.

Before the discovery, scientists had guessed that dinosaurs, like modern reptiles, must have laid eggs, but no clear evidence of that had ever been found. Eggs are fragile structures, and fossils were assumed to be unlikely. Fossils of eggs and juvenile dinosaurs have continued to be rare. John Horner (the paleontologist who discovered the eggs, nests, and fossils of babies of Maiasaura in 1981) has called the discovery in the Gobi “spectacular” and has referred to the absence of further eggs and juveniles as “a major scientific puzzle.” After Horner found dinosaur embryos in Montana, he carefully studied a Protoceratops egg from Flaming Cliffs and stated that the supposed bones were only calcite crystals in odd shapes. Expectations can affect observation. Andrews’s staff had seen a bit more than was actually there, but the eggs were still eggs.

The excitement and romance of the expeditions firmly established the reputation of the American Museum of Natural History. With the expeditions, the museum built and still boasts the largest collection of dinosaur fossils in the world. Furthermore, the museum was able to develop outstanding exhibits and also to function as a continuing resource of specimens for further scientific study.

The expeditions did not find evidence to support Osborn’s theory about Asia being the center of human evolution. In fact, they did not uncover a single early human bone. Andrews, however, proposed that the relationship of Protoceratops to Triceratops supported the idea of a land bridge to North America by which life spread. He wrote in his journal that “the theory upon which we organized the expedition might be true; that Asia is the mother of the life of North America.” Scientists believe that it certainly was a center of some sort, but not for humankind. Research concerning the origins of humans is now centered on Africa.

Science changes and is influenced by many ideas. Scientists have continued to reinterpret the findings at Flaming Cliffs to fit new and better theories. Nevertheless, the expeditions remain a landmark in that they contributed much to the progress of paleontology. The science of dinosaurs has undergone major changes, but the eggs and other fossils from the Flaming Cliffs continue to rank as outstanding discoveries in human beings’ efforts to understand the past. Dinosaurs Paleontology Fossils;dinosaur eggs

Further Reading
  • citation-type="booksimple"

    xlink:type="simple">Andrews, Roy Chapman. “Explorations in the Gobi Desert.” National Geographic 63 (June, 1933): 653-716. Provides a feeling for the time when the discovery was made. Features many photographs by Shackleford, including one that shows the cliff on which Lovell and Granger found the best nest.
  • citation-type="booksimple"

    xlink:type="simple">_______. On the Trail of Ancient Man: A Narrative of the Field Work of the Central Asiatic Expeditions. 1926. Reprint. Whitefish, Mont.: Kessinger, 2004. Andrews’s own account, written in the first person for the lay reader, still conveys the excitement of the discoveries and the adventure of exploring the unknown. Describes sandstorms, finding fossils, dealing with danger, and finding the dinosaur eggs.
  • citation-type="booksimple"

    xlink:type="simple">Gould, Stephen Jay. Wonderful Life: The Burgess Shale and the Nature of History. New York: W. W. Norton, 1989. Addresses the nature of interpreting the fossil record, skillfully using the details of the Burgess Shale of British Columbia to reveal the human side of science, showing how different interpretations of evidence can tell different stories. Written in elegant and witty style.
  • citation-type="booksimple"

    xlink:type="simple">Horner, John R., and James Gorman. Digging Dinosaurs. New York: Workman, 1988. Relates the exciting story of Horner and Robert Makela’s discoveries and interpretations of hadrosaur nests found in Montana late in the twentieth century. Horner is among those who hold that various dinosaurs were birdlike and performed social behaviors such as protecting and feeding their young.
  • citation-type="booksimple"

    xlink:type="simple">Johanson, Donald, and James Shreeve. “The Antiquity of Man.” In Lucy’s Child: The Discovery of a Human Ancestor. New York: William Morrow, 1989. Presents the history of how the search for the site of the evolution of humans shifted over the years from Africa to Asia and back to Africa. Discusses the influence of culture on scientific endeavor.
  • citation-type="booksimple"

    xlink:type="simple">Lambert, David. The Dinosaur Data Book: The Definitive, Fully Illustrated Encyclopedia of Dinosaurs. New York: Avon Books, 1990. Comprehensive, lavishly illustrated volume shows how ideas about dinosaurs have changed considerably since the time of the Andrews expedition. Includes information on major fossil sites.
  • citation-type="booksimple"

    xlink:type="simple">Lessem, Don. “Secrets of the Gobi Desert.” Discover 10 (June, 1989): 40-46. Relates the efforts of Canadian and Chinese scientists to retrace the steps of Andrews’s expedition and notes that fossil bones found late in the twentieth century continued to indicate that the dinosaurs may have spread to one another’s continents.
  • citation-type="booksimple"

    xlink:type="simple">Martin, Anthony J. Introduction to the Study of Dinosaurs. 2d ed. Malden, Mass.: Blackwell Science, 2006. Comprehensive college-level textbook aimed at both science students and non-science majors includes discussion of the history of dinosaur studies. Features end-of-chapter references, glossary, and index.
  • citation-type="booksimple"

    xlink:type="simple">Norell, Mark, Lowell Dingus, and Eugene Gaffney. Discovering Dinosaurs: Evolution, Extinction, and the Lessons of Prehistory. Expanded ed. Berkeley: University of California Press, 2000. Focuses on what the fossil record reveals about dinosaurs’ evolution and extinction. Includes maps and illustrations.

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Categories: History