Uploaded November 2015 | Updated September 2026, 1 week ago

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Paleontologists today look at more than just fossil evidence to learn about organisms that lived millions of years ago. In this case, we're seeking to answer the question: how, and when, did mammals evolve their specialized movements? Turns out, the next step in this process involves dissecting a giant weasel...

This is part one in a three-part series supported in part by The Field Museum, the Museum of Comparative Zoology at Harvard University, and The National Science Foundation (!!!!).

Big thanks to Drs. Ken Angielczyk, Stephanie Pierce, and Katrina Jones for their immense help and accommodation during the creation of this series.

Want to learn more about this research? Here's the gist:

Mammals are known for their great range of locomotor behaviors, including unique gaits such as galloping and bounding. These gaits are made possible by the subdivision of the backbone into two distinct regions: the thoracic region, which bears ribs and aids in breathing; and the lumbar region, which is ribless, highly mobile and functions in locomotion. Combined, these two sections of the backbone allow mammals to breathe and move simultaneously, permitting the use of high speed gaits for prolonged periods of time. But, how did this key mammalian trait evolve? Using cutting-edge 3D technology, along with the rich fossil record of mammals and their ancestors, this research will trace the origin and evolution of the mammalian backbone and its link with the development of mammal-specific locomotor behaviors. The work will deepen our understanding of the history of a key characteristic of mammals and part of the skeleton that is of great medical importance.
Retrieved from: http://1.usa.gov/1MHCXQm

"Dimetrodon is Not a Dinosaur"
youtu.be/-tdVPiyVDsQ

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Producer, Writer, Creator, Host:
Emily Graslie

Producer, Editor, Camera, Graphics:
Brandon Brungard
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Filmed on Location and Supported by:
The Field Museum in Chicago, IL
(http://www.fieldmuseum.org)

The Museum of Comparative Zoology at Harvard University:
(http://www.mcz.harvard.edu/)

The National Science Foundation:
Grants NSF EAR-1524938 and EAR-1524523
(http://www.nsf.gov)