Seeing Double: How The Field Museum Makes Fossil Casts
Lumbering bear-like creatures that browsed Paleocene forests called pantodonts are some of the many fossil mammals immortalized at The Field Museum. They’re some of the first large mammals after the extinction of dinosaurs, and despite their intimidating canine teeth, they were herbivores. While these animals were likely a dominant species in their time, today they are represented by a limited number of excavated fossil specimens.
Millions of visitors enter The Field Museum every year with the opportunity to stand face to face with a pantodont, the Barylambda skeleton on display in our Evolving Planet exhibition, and imagine from its stoic fossil what this early mammal was like. It is a chilling, stirring experience to see the shape of an animal that hasn’t been alive on earth for 56 million years. Unfortunately, not everyone has the means or the time to trek to Chicago to see what The Field Museum has to offer, but that does not mean they will never see a pantodont. The Field Museum works with museums around the world to make our specimens, including rare pantodonts, accessible to both scientists and the public.
In early 2012, The North Dakota Geologic Survey contacted Field Museum paleontologist Bill Simpson requesting a replica of one of our pantodont specimens, a Titanoides, for their museum to display. Simpson agreed, and sent off the fossils to North Dakota where fossil preparators at The North Dakota Geologic Survey planned the molding process to replicate this enormous figure from our delicate fossils. This fall, the North Dakota Geologic Survey sent us photos of their new exhibition, with casts of our Titanoides specimens arranged in a death pose as though they had just been uncovered in the field.
After many hours of work, the multi-part molds are made, and from them, all the casts of Titanoides are created. The most obvious difference between the real fossil and its cast is the color—the cast is a clean, off-white color that has no stains from time like the brown and gray smattered original. Other than that though, the shapes are almost exactly identical, including the same bumps, grooves and blemishes. It has one extra scar though, a seam line where the pieces of the mold came together. Without having to leave The Field Museum, Titanoides’s stirring presence can now be felt in North Dakota as well.
This cooperative sharing of collections, casts, and data occurs throughout the scientific and museum community worldwide. At The Field Museum, although a specimen may be exhibited behind glass or preserved in a collections cabinet, it is still accessible for scientific use. Through digital records, physical molds, and even the not-infrequent mailing of real specimens, even the most delicate, rare objects and fossils can be marveled at and studied by scientists and the public. These rare pantodonts such as our Barylambda and Titanoides specimens continue to serve important purposes here at The Field Museum. Barylambda is one of the few pantodonts on display anywhere, viewed by countless visitors, and both Barylambda and Titanoides are available here for research by paleontologists from around the world. And now, casts of our Titanoides are reaching visitors hundreds of miles away in North Dakota.
Matt Curran is an intern in the Public Relations department at The Field Museum.
