The Real Monsters of the Midway: Mammoths and Mastodons of the Chicago Region

Roy Plotnick
8 min readMar 26, 2021

On October 25, 1880, workers putting in a sewer line along Fowler Ave. (now Schiller St.) just west of Wicker Park on the north side of Chicago, made an unexpected discovery. Some 13 feet down, in a layer of peat and muck, they found the tooth, a rib, and a portion of a tusk of what was then identified as a mastodon. The fossils were put on display in the mayor’s office, eventually ending up in the collections of the Chicago Academy of Sciences (the tusk is still there; it is not clear where the tooth and rib are). I recently had a chance to examine the tusk and reidentified the animal as a mammoth, based on its internal structure[i], an interpretation supported by paleontologist Chris Widga of East Tennessee State University.

These fossils remain the only fossil proboscideans (the extinct mammoths and mastodons) found within the city limits. Nevertheless, occurrences of both ancient animals are found throughout the region, telling us that they were common animals of the area before their unfortunate extinction and thus part of our geoheritage. They are still rare enough as fossils, however, that every occurrence is of note. Before I summarize what is known, it is important to briefly distinguish between the two extinct mammals (for more details, see All About Mastodon).

Mammoths (Mammuthus) are closely related to modern Indian elephants (Elephas maximus), with both related to African elephants (Loxodonta africana). Wooly mammoths (Mammuthus primigenius) are bit smaller than African elephants whereas the Columbian mammoth (Mammuthus columbi) was somewhat larger. The molar teeth of mammoths resemble those of modern elephants, flat and resembling the surface of an old-fashioned washboard. According to Saunders and his colleagues, two species of mammoth are common in Illinois: Mammuthus jeffersonii and Mammuthus primigenius.

Mastodons (in the eastern United States, Mammut americanum), in contrast, split off from mammoths and elephants some 25-million-years-ago. They are smaller than both African elephants and mammoths and have teeth with deep cusps. The tooth shape is responsible for their name (mastodon = “breast-tooth”). Since teeth are by far the most commonly preserved parts of the animal, their distinct shapes make them easy to distinguish from mammoths. The differences in teeth shape also reflects a difference in diet; mammoths were grazers whereas mastodons both grazed and browsed.

The following are places where mastodons and mammoths have been described from the Chicago region (Cook, Lake, DuPage, and Will counties). I have broken them down by county and town. This list is mainly derived from a database maintained by Chris Widga, the collections of the Chicago Academy of Sciences and the Field Museum, the Neotoma database, and contemporary articles (e.g., Anderson 1905) and newspaper reports. I will emphasize where you can go to see them yourself.

Cook County

· Evanston: A mammoth tooth was reported in 1905 from a gravel pit near Evanston, supposedly deposited in the long defunct natural history museum at Northwestern University. Current whereabouts unknown.

· Glencoe: A fragment of mammoth tooth was found in glacial deposits ca. 1905.

· Forest Park: The tusk and teeth of a mammoth were unearthed in a gravel pit in the Forest Home cemetery in 1856. The specimens are in the collections of the Chicago Academy of Sciences and the Forest Park Public Library but are not on display. I wrote about this in: A mammoth in Forest Park.

Forest Park mammoth tooth

· Orland Park/Tinley Park: A partial skeleton of a Columbian mammoth, collected in 1979 near Orland Park, 23 feet below a layer of peat. In collections of the Field Museum.

· Bolingbrook: Mastodon lower jaw, unearthed during the excavation of the Stevenson Expressway (I-55), just west of the Des Plaines River. On display at the Field Museum (see photo).

Bolingbrook mastodon, on display at Field Museum.

· Western Springs. The Field Museum collection has a rib and metapodial of a Columbian mammoth collected in 1938. No additional information.

DuPage County

· Wheaton: In 1869 bones of a mastodon was reported found on the Jayne farm, with the public being charged $0.25 to view them. A mammoth was unearthed about 1890 on the Jewell farm.

· Glen Ellyn: The nearly complete Perry Mastodon was discovered in 1963 while digging a pond on the property of U.S. Federal District Court Judge Joseph Perry. The mastodon is on display at Wheaton College (see photo). Based on Carbon-14 (radiocarbon) dating, the mastodon died between 13,550–13,240 years ago.

The Perry Mastodon. At Wheaton College.

· Wayne: The Brewster Creek mastodon at Pratt’s Wayne Woods Forest Preserve. Skull fragments, teeth, rib of a mastodon found during wetland restoration in 2005. Additional material was uncovered in 2008. The specimens are currently stored at the DuPage County Forest Preserves collections space at Mayslake Peabody Estate in Oak Brook.

· Warrenville: A group from Northern Illinois University in 1977 unearthed a 75% complete skeleton of mammoth in 1977 at the Blackwell Forest Preserve’s McKee Marsh, about ¼ mile east of the West Branch of the DuPage River. The skull was missing. On display at the Fullersburg Woods Nature Center in Oak Brook (see photo).

Mammoth on display at Fullersburg Woods Nature Center

· Carol Stream: Mastodon specimen in collection Field Museum.

Kane County

· Aurora: If there is an epicenter for mastodons in the region, it is Aurora. In August 1850, workers excavating what was then the Aurora Branch Line discovered four mastodon teeth and two tusks. They are now the property of the Aurora Historical Society and are in storage at the Tanner House Museum. A large bone was reported found in 1870 when digging a well. Most importantly, a 1934 excavation for a municipal lake in Phillips Park uncovered a trove of Pleistocene fossil, including parts of at least four mastodons. The remains are on display at the Phillips Park Visitors Center & Mastodon Gallery, on loan from the historical society. Based on radiocarbon, the mastodons died about 13,000 years ago. Discoveries have continued since then. A 1970 article in the Chicago Tribune reported the “21st mastodon to be discovered in that community since 1934”.

Phillips Park mastodon

· Batavia: Prior to 1905, mastodon legs and vertebrae were found in a ditch built to drain a marsh.

·Maple Park: A large portion of a mastodon skeleton was unearthed ca. 1909 about 3.5 miles south of town. The photo below is from Bagg (1909), attributed to Aaron Hummel. This may be same specimen shown in a photo in the archives of Northern Illinois University, labeled “September 17, 1907: Mastodon excavation on the farm of Jacob Hochstrasser, located three miles south of Maple Park, IL. Pictured here is biology professor Fred Charles and President Cook, the Hochstrasser farmers and the the excavation team with one of the leg bones.” (

Photograph of a mastodon skeleton unearthed at a depth of 6 feet from 3.5 miles south of Maple Park (photo from Bragg 1909).

Lake County

· Ingleside. While digging a canal on his property in 1925, Herman Kaping recovered the rib bone and vertebra of a mastodon. These were sent to the Field Museum, but the specimens are currently missing from the collections. A leg bone collected at the same time is on display at the Bess Bower Dunn Museum in Libertyville.

· Wadsworth. In 1992, a tusk and numerous bones of a mastodon were unearthed when a marsh area was converted into a lake. The remains are at the Illinois State Museum.

Widga and his colleagues summarized data on 659 mammoth and mastodon sites from the North American midcontinent. Based on more than ninety dated individuals, they estimated that the extinction of these proboscideans occurred about 12,500 years ago. Their disappearance is only a blink ago in the length of geologic time.

But why did they disappear? The glib answer is that we don’t really know. One of the most contentious subjects in paleontology and archaeology is what happened to the mammoths, mastodons, and other large mammals of the Pleistocene. Their disappearance generally coincided with the end of the last ice age and the first appearance of humans in the Americas. There are ardent proponents of climate change, human hunting, or some combination of the two. I lean to the last of these, but don’t expect the question to be answered any time soon. All I can do is go to the museum and stand in awe of these lost giants.

Thanks to: Chris Widga (EKU), William Simpson (Field Museum), Dawn Roberts (Chicago Academy of Sciences), Diana Dretske (Dunn Museum), John Jaros (Aurora Historical Society) and Kevin Leonard (Northwestern University) for providing invaluable information.

For more reading:

Adams, S. C., and G. H. Fraunfelter. 1974. The composition and characteristics of the molluscan fauna associated with the Perry Mastodon of Glen Ellyn, Illinois. Transactions of the Illinois State Academy of Science 67:202–208.

Anderson, N. C. 1905. A preliminary list of fossil mastodon and mammoth remains in Illinois and Iowa. Augustana Book Concern Printers, Rock Island.

Bagg, R. M. 1909. Notes on the distribution of the mastodon in Illinois. The University Studies, 3:46–56.

Powers, W.E. 1935. Geological setting of the Aurora Mastodon remains. Transactions of the Illinois State Academy of Science 28(2):193–194.

Smith, C.R. 1935. Mastodon and other finds in Aurora. Transactions of the Illinois State Academy of Science 28(2):195–196.

Springer, J.W., and R.C. Flemal. 1981. Paleontological and geological results from two fossil proboscidean finds in northern Illinois. Transactions of the Illinois Academy of Science 74(3–4):87–99.

Saunders, J. J., E. C. Grimm, C. C. Widga, G. D. Campbell, B. B. Curry, D. A. Grimley, P. R. Hanson, J. P. McCullum, J. S. Oliver, and J. D. Treworgy. 2010. Paradigms and proboscideans in the southern Great Lakes region, USA. Quaternary International 217(1):175–187.

Widga, C., S. N. Lengyel, J. Saunders, G. Hodgins, J. D. Walker, and A. D. Wanamaker. 2017. Late Pleistocene proboscidean population dynamics in the North American Midcontinent. Boreas 46(4):772–782.

[i] We used what are called Schreger angles, chevron like structures visible on cross-sections of ivory. Mastodons and mammoths have very different Schreger angles. The same method is used to determine if ivory is fossil proboscidean or modern elephant. A fossil giant beaver was discovered while building the Pritzker School at or near the same locality. In the 1934, the great geologist J. Harlan Bretz mapped this as former shoreline beachof post-glacial Lake Chicago.



Roy Plotnick

Paleontologist, geologist, ecologist, educator. Professor at the University of Illinois at Chicago. Author of Explorers of Deep Time.