Press release

This was the announcement the University released to the press this week.  We’re grateful to the NSF for their continuing support and to all the volunteers working on the project who make it possible.  Our sincere thanks. Holmes and Dave

UI sloth excavation project awarded $20,000 NSF grant

The University of Iowa’s Tarkio Valley Sloth Project has been awarded a $20,000 grant from the National Science Foundation (NSF) to complete the excavation of the remains of three giant sloths and begin research of this unique discovery. The project is a joint effort of the UI Museum of Natural History, Department of Geoscience in the UI College of Liberal Arts and Sciences, and Office of the State Archaeologist, all teaming up with volunteers and students from across the Midwest.

A skeleton of a giant Ice Age sloth was discovered by Bob and Sonia Athen in 2001 behind their home near Shenandoah, Iowa, in the bed of the West Tarkio Creek. More bones were subsequently found on the property of the adjoining landowners, Dean and Loreta Tiemann, who, like the Athens, graciously agreed to allow the excavation and to donate the fossils to the University of Iowa.

The elephant-sized beast lived in Iowa for thousands of years before going extinct around 12,000 years ago. To date, more than 100 major elements have been recovered, making this individual the second-most-complete skeleton ever found of this rare species. In 2006, two juvenile sloths of the same species were discovered nearby.

According to project leader Holmes Semken, emeritus professor in the UI Department of Geoscience, only six semicomplete skeletons of this species have ever been found and this is the first time any juvenile, much less two, has been found directly associated with an adult. They also are buried in sediments that will provide valuable environmental data about the climate at the time.

“This could be our ‘Rosetta Stone’ for understanding the family life of these mysterious creatures,” Semken said. Over 40 bones of the older juvenile have been recovered, making it also the second most-complete juvenile of its kind ever found.

“The NSF is excited about the discovery and has indicated that we can count on their continuing support if we keep making progress like we have,” said Semken. “They see the potential here for a major contribution to our understanding of the Pleistocene extinction event in which almost 40 large mammals became extinct at the same time. They also realize they are getting a lot of bang for their buck through the tremendous support we’ve received from the university, the Page County community, the Iowa Archaeological Society, Mid-American Paleontological Society, the Boy Scouts, Iowa Academy of Science, and staff and students from educational institutions all across Iowa.”

The project has also received assistance from the U.S. Department of Agriculture, the U.S. Army Corps of Engineers, the U.S. Geological Survey and the National Park Service.

“It’s a breakthrough project for the university,” said sloth project co-leader David Brenzel of the UI Museum of Natural History. “The NSF recognized that our goal to educate people about the process of doing science is as important as the research itself. They are providing specific funding to expand our educational outreach efforts through public programs and the Web.”

Last month, a blog was started about the project at, which can also be found by going to

The blog will allow anyone interested in the project to submit questions and contribute ideas. We hope it will be fun, educational, attract some professional interest, and also inspire young paleontologists,” Brenzel said. Photos of the dig and associated lab work are available at

For further information or to volunteer for the project contact Sarah Horgen at the UI Museum of Natural History, [email protected], Semken at [email protected], or Brenzel at [email protected].

STORY SOURCE: University of Iowa News Services, 300 Plaza Centre One, Suite 371, Iowa City, Iowa 52242-2500

MEDIA CONTACTS: Sarah Horgen, UI Museum of Natural History, [email protected], 319-335-0606; George McCrory, University News Service, 319-384-0012, [email protected]