Collections & Archives

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Our scientific collections date back to our founding in 1857.

Our scientific collections have been built since that time and have been used to help define human understanding of nature, ecology, and the diversity of life in the United States. The Academy’s collections include:

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Herpetology is the study of reptiles as well as the more distantly related amphibians. Reptiles include lizards, snakes, turtles, crocodiles, and amphisbaenians, while amphibians include frogs, toads, salamanders, and caecilians. Reptiles and amphibians are typically preserved as whole specimens in alcohol. The Academy’s collection includes more than 23,200 specimens and is particularly strong in Midwestern herps as well as Southwestern rattlesnakes. This latter collection was made by Academy Director Howard K. Gloyd as part of writing the seminal book “The Rattlesnakes: genera Sistrurus and Crotalus.”

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Mammalogy is the study of mammals. Mammals are typically preserved as dry skins along with the skull and other bones. The Academy’s collection of 5,200 specimens contains mostly small mammals native to the Midwest but also includes Appalachian species collected during Academy surveys that highlighted the exceptional biodiversity of this region and contributed to the Great Smoky Mountains becoming a National Park.

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Ornithology is the study of birds. Birds are preserved as dry skins. The Academy’s collection includes more than 13,900 specimens representing 580 species. Most of our specimens are species that occur in the Midwest, though many of these species are migrants that are also native to South America and Canada. Some specimens were collected by Academy Director Alfred M. Bailey as part of his work to document avian diversity in his highly regarded book “Birds of Arctic Alaska.” The collection includes many examples of extinct species such as the passenger pigeon, Carolina parakeet, ivory-billed woodpecker and Eskimo curlew.

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Oology is the study of eggs. The Academy collection is primarily bird eggs but we also include bird nests among our 11,200 specimens, the majority of which were collected in the late 1800s and early 1900s. Notably, our collection includes eggs of the extinct passenger pigeon and the first documented nesting of the Kittlitz’s murrelet, collected from Cape Prince of Wales (Alaska).

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Entomology is the study of insects—a group that comprises more than 70% of named species. Insects are typically preserved as dried and pinned specimens. The Academy’s collection contains nearly 71,100 insect specimens, primarily Lepidoptera (butterflies and moths) and Coleoptera (beetles), and some related arthropods.

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Malacology is the study of mollusks—soft bodied animals that include snails and slugs, clams and squids. Conchology is the study of the shells these animals make. This is the Academy’s largest collection with over 113,300 specimens of primarily freshwater and terrestrial species but also includes marine snails and other groups. Notably, we have a large, early collection of Unionidae. These are freshwater clams that are very diverse in our region and are the most endangered group of animals in the world. Another key portion of the collection comes from former curator Frank C. Baker, whose pioneering work on freshwater gastropods is cited to this day.

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Paleontology is the study of prehistoric life based on fossil evidence. The Academy’s collection contains more than 23,200 specimens, many of which come from the Mazon Creek area along with other representatives from Silurian and Devonian deposits in the Midwest and some early Green River fish. Among our prominent collectors is Jonathan H. Britts, a specialist in Pennsylvanian plant fossils. Many of our specimens are from localities that are no longer accessible.

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Geology is the study of the history of the earth as recorded in rocks. The Academy collection contains more than 11,100 specimens of rock and mineral specimens from around the Midwest, some representing mines and other localities that are no longer accessible.

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Botany is the study of plants. Most specimens are preserved by pressing and drying the leaves, stems, roots, flowers, and fruit then affixing them to acid-free paper, along with their data label. Wood samples may be stored separately and fleshy fruits may need to be freeze-dried. Many of the 15,600 specimens in our collection were collected prior to 1900 in the Chicago Wilderness region but we also have specimens from Cuba, parts of Europe, and significant specimens from a U.S. Army expedition west of the 100th meridian. Prominent collectors include Herman S. Pepoon, Elizabeth E. Atwater, and Henry C. Cowles.

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The Academy photography collection includes thousands of still photos and more than 1,300 motion pictures representing some of the earliest natural history photography. Many were made by Academy scientists and local naturalists who were using the then new technology to study the Chicago Wilderness region. Many of their images record now lost landscapes of the Midwest.

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The Academy’s archives contain more than 100 linear feet of manuscripts and 400 linear feet of institutional records and ephemera including field journals, maps and drawings, and publications. The collection is strongly focused on the Midwest and documents local naturalists’ studies of the region’s ecosystems, flora, and fauna. Types of materials include letters and personal correspondence, field notes, maps, drawings, research files and notes, printed materials, scrapbooks, photographs, meeting minutes, calendars, ephemera, and other materials.

Finding aids are available for the manuscript collections. A list of the manuscript collections can be accessed here. Please contact the Collections Department at to request additional information or to schedule an appointment to visit the archives.

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The cultural collection contains a wide range of artifacts from anthropological artifacts to topical art and historical scientific instruments. Most of the materials were acquired as part of our other natural history studies.

Accessing our Collections & Archives

You can explore some of our specimens and collections by checking out our Google Arts & Culture page or by searching Arctos. Or you can explore historic and staff publications.




Want to learn more? Check out our behind-the-scenes tour of the Collections facility below. Plus, use the navigation to jump to a specific section.

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About the Collection

Specimens in a collection are like a physical snapshot in time, containing irreplaceable information. Often, the knowledge that can be obtained through careful study of these authentic artifacts was not anticipated when the specimen was collected.

For example, a peregrine falcon collected in 1873 contains DNA, even though this molecule was unknown by scientists when the bird was put in our collections. Similarly, the eggs of this specimen might be compared with those of a more recent one to discover and quantify the effect of bioaccumulated toxins like DDT. In fact, egg shells from the 1800’s are thicker and have a stronger calcium and phosphorus matrix than do those collected in the 1960’s. As a result, peregrines became extirpated (locally extinct) in the eastern ¾ of the United States. Though the species has largely recovered (thanks to careful regulations, captive breeding, and reintroductions) the genetics of the population have changed. All of this is known because of specimens that were collected and preserved before the crisis occurred.

Through such natural history specimens, we have a physical, empirical record of the past. We can use these specimens to interpret our present place in history which then allows us to anticipate future conditions. This power to hold the past, understand the context of the present, and predict the future makes natural history collections an important and unique human resource.

Scientists and historians frequently access the collections while working on research projects. Nature Museum members and other groups also may have opportunities to take a special tour at the Collections Facility.

The museum collections have never been more accessible, thanks to grants from the Institute of Museum and Library Services (IMLS) and the Gaylord and Dorothy Donnelley Foundation. As of August 2012, every specimen in our collections was inventoried and digitally catalogued. Searches that used to take months now take minutes.

The number of specimens in each collection varies. Here is a “by the numbers” snapshot that just scratches the surface of the collections.




bird eggs & nests




amphibian & reptiles


insects & spiders






linear feet of manuscripts & other paper records


motion picture films


cultural artifacts


photographic images




geologic specimens

Use & Access

The scientific collections and archives are stored at our off-site collections facility in the Ravenswood neighborhood. For research inquiries, please contact the Collections Department via email at Research visits to the collections facility are by appointment only. Information regarding use of and access to the collections may be found by clicking here. We also have a non-lending library at the collections facility available for use on-site. The library catalogue is available through LibraryThing.

Our Education Department offers various programs for schools and teachers, such as Nature on the Go, that integrate specimens from the collections.

Frequently Asked Questions

Contact the Collections Department at with additional questions or inquiries.

The data vary between different types of collections but a specimen should always include a data tag with the common and scientific name, where, when, and who collected the specimen, a description of the specimen’s habitat, and some basic measurements of the specimen such as weight in grams and length in millimeters. These data are used by a wide range of scientists from ecologists to taxonomists. Since we have so many specimens from more than a century ago, our collections are particularly valuable in showing change over time and predicting future trends.

There are many uses for specimen data including morphoplogical (attributes like size, shape, or color), chemical (attributes like DNA or isotopic signatures), and historical (attributes like distribution or population density). For example, a herpetologist may want to compare the present distribution of cricket frogs in Illinois with their historic distribution. Our collection database can supply the answers. In this case, the data show that cricket frogs have disappeared from much of their former range. If the scientist then needs to use specimens from the early 1900’s to look for changes in chemical residue, bone structure or some other feature, our collection can supply them. Because we have the actual specimens, we can learn facts about the past that were not known at the time. By comparing this with current data we can then anticipate future trends.

Another use for natural history collections is morphometrics—the analysis of a species based on measurements of many specimens. These data, along with distribution data also gleaned from museum collections, form the basis of field guides. If you’ve ever gone bird watching or used a book to identify a plant, you’ve used data from a collection.

The specimens in a natural history collection are like physical snapshots in time. They record data that cannot be reproduced. In many cases, questions that can be answered by the specimens were not anticipated when the specimens were collected. For example, all biological specimens contain DNA but, as far as scientists in the 1800’s knew, DNA did not exist. Yet, as an intrinsic part of the specimen, they collected and preserved that data along with the specimens they deposited and today that DNA can help us understand more about the past and the present.

As our knowledge of the natural world grows and as we create new ways to gather information, the questions that can be answered by specimens increases. In the past, a scientist often used measurements of a specimen’s bones to distinguish one species from another. Such measurements are still important data points but today we can also use DNA from those same specimens to understand the evolutionary path that resulted in the two species in the first place. Since the specimen is a physical record from the past, it contains irreplaceable information that awaits a creative scientist with the right tools. In the future, scientists will still be using old specimens to answer new questions.

Some examples of how Academy specimens have been used in different ways include: analysis of preserved stomach contents to learn about the diet of baby massasauga rattlesnakes; measurement of Ivory-Billed and Pileated woodpecker bills to determine the width of the chisel marks left in trees by large northern individuals and small southern individuals; and chemical extraction to quantify the stable isotope ratio in the fur of urban and rural squirrels as a way to show dietary changes across an urban/rural gradient and through time.

Academy scientists have been collecting and preserving examples of local biodiversity for more than a century and a half. Most of these specimens have been made into study skins and are used for scientific analysis that is later published in the form of peer-reviewed papers and field guides. Most of your knowledge of nature has its roots in information first published by scientists using study skins.

Some specimens have been mounted in life-like poses for use in exhibits. This kind of taxidermy takes considerable skill, artistry, and time but results in a specimen that shows the beauty and drama of a living animal. Such specimens allow a visitor to see details that you could never observe on a living individual. For this reason, artists, commercial photographers, and movie companies have used our specimens.

Mounted specimens and study skins may also be loaned to other institutions to complete a study or augment an exhibit.

Specimen data, field notes, and photographs often accompany specimens. Such information is used widely by historians, authors, and scientists as they document the past, interpret the present, and imagine the future.

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