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University of Iowa News Release


April 24, 2009

Museum of Natural History begins anniversary celebration with sloth talk May 7

World-renowned Ice Age sloth expert Greg McDonald will open the University of Iowa Museum of Natural History's yearlong celebration of its 150th anniversary with a lecture at 7 p.m. on Thursday, May 7, in Macbride Auditorium. A reception at 6 p.m. in the museum's Iowa Hall will precede the talk, which is part of the museum's Explorers Seminar Series. Both events are free and open to the public.

The senior curator of natural history for the National Park Service's Park Museum Management Program, McDonald serves as a consultant for the museum's Tarkio Valley Sloth Project -- an ongoing excavation of three giant Ice Age sloths in western Iowa. In addition, he was the scientific consultant when the museum built the Ice Age sloth model for its Iowa Hall gallery in 1985.

For his talk, titled "The Museum and the Megalonyx: A History of Great Aspirations and Sloths in Iowa," McDonald will discuss the museum's Tarkio Valley excavations and the history of the museum's geologic research and collections.

"This program is a great illustration of how field work can strengthen a museum's exhibitions and displays," said Pentacrest Museums Director Pamela White. "We're pleased to continue to offer these important opportunities as we celebrate 150 years of discovery at the museum."

A vertebrate paleontologist, McDonald has studied at the University of Toronto, the University of Florida and Idaho State University, and his research interests focus on the Pleistocene (Ice Age) mammals of North and South America, particularly the extinct giant ground sloths and their relatives.

"He is without a doubt the world's top expert on these animals," said Sarah Horgen, the museum's education and outreach coordinator. "There's nobody better we could have gotten to talk about this project."

The Tarkio Valley Sloth Project was recently awarded $20,000 by the National Science Foundation to complete excavation and begin more wide-ranging research on the discovery. McDonald's visit is made possible by that grant, and he will work on analysis of the recovered bones while on campus.

Horgen said that the sloth excavation is the perfect topic to begin their anniversary celebration. "The museum used to send expeditions around the country and the world to gather scientific data and specimens for the museum," she said. "The sloth dig is truly another chapter in that longstanding history."

The Tarkio Valley Sloth Project, a joint effort between the UI Museum of Natural History, Department of Geoscience and Office of the State Archaeologist with volunteers and students from across the Midwest, began in 2001 when Bob and Sonia Athen uncovered a giant Ice Age sloth, called Megalonyx jeffersoni, in the bed of the West Tarkio Creek behind their home near Shenandoah. Soon, more bones were found on the property of the adjoining landowners, Dean and Loreta Tiemann. Both the Athens and the Tiemanns graciously agreed to permit excavation and donate the fossils of this rare species to the University of Iowa.

M. jeffersoni, an elephant-sized Ice Age beast, lived in Iowa for thousands of years before its extinction about 12,000 years ago. Only six semi-complete skeletons of this species have ever been found. To date, the Tarkio Valley adult is the second most complete skeleton of its kind, and in 2006 two juvenile M. jeffersoni were discovered near the adult sloth, making the site the first of its kind.

Project leader Holmes Semken, emeritus professor in the UI Department of Geoscience, said this is the first time any juvenile -- much less two -- has been found directly associated with an adult. The older juvenile is also the second most complete of its kind ever found, with more than 40 bones recovered. The skeletons have the added research benefit of being buried in sediments that will provide valuable environmental data about the climate during the sloths' lives.

"We are hoping to uncover information that is relevant to people's lives," Horgen said. "Scientists believe that by looking at what caused climate change years ago and the affect of climate change on different groups of animals we can hopefully learn what's happening with current climate change issues and extinctions that are taking place. Even though they have different causes, we might able to help remedy some of the effects."

The Museum of Natural History has been in existence for over 150 years. It was established in 1858 when the Iowa General Assembly directed the University to house specimens from the State Natural History and Geological Surveys in a cabinet of natural history to be located in the Old Capitol building.

Other events marking the museum's anniversary include:

--Ice Age Sloths in Our Backyard: Open House and Special Events, Friday, May 29, and Saturday, May 30, at the Greater Shenandoah Historical Museum in Shenandoah. UI researchers will review the history of the Tarkio Valley Project, show a short video of the dig, present the first public display of the Tarkio Valley toddler specimens alongside distinctive elements from the adult specimen, and conduct an "Artifact and Fossil Roadshow," where visitors can bring in their finds for identification, among other activities.

--"The Museum Goes to the Fair: Rediscovering the Philippine Collection at the University of Iowa Museum of Natural History," a special exhibition opening August 28 in Old Capitol Museum's Hanson Family Humanities Gallery. The exhibit will feature selections from Museum of Natural History's Philippine collection. Originally created for or displayed in the Philippine Reservation that spanned over 40 acres at the 1904 World's Fair in St. Louis, objects on display will include baskets, textiles, utensils, musical instruments, weapons, and fishing and agricultural implements -- many of which have not been on view for over 100 years.

The University of Iowa Museum of Natural History features three permanent galleries exploring natural history and emerging environmental research in Iowa and beyond. For more information call 319-335-0606 or visit

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, 319-335-0606,; George McCrory, University News Services, 319-384-0012,; Writer: Maggie Anderson

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