The Ottumwa Courier

February 25, 2014

Ottumwa native gives update on mammoth excavation

Courier staff writer

---- — OTTUMWA — After two summers full of discovery at the Mahaska County mammoth excavation site, the research team is readying for its third season.

Native Ottumwan Sarah Horgen, education and outreach coordinator for the University of Iowa’s National History Museum and a 1998 Ottumwa High School graduate, was in town Tuesday to give an educational presentation about mammoths and an update on the project at the Reminisce Society meeting at the Ottumwa Public Library.

“My job is education,” Horgen said. “Part of my job is to go around the state teaching. I’m from Ottumwa, so whenever someone from here wants me to present, I will.”

In her presentation, Horgen said the mammoth remains found in Mahaska County come from the last ice age, which ended around 10,000 years ago. The Des Moines area was as far south as the glaciers went during that ice age, she said, and everywhere else in Iowa was generally open prairie with a winter-like climate, perfect for mammoths.

Several species of animals that went extinct right after the last ice age, such as mammoths, would have been found in high numbers across the state. Dire wolves, North American horses, mastodons, bison, giant sloths, caribou, giant beaver, muskox and even camels were natives of the land back then.

“There were some very strange creatures running around,” Horgen said in her presentation.

Within a 1,000-2,000 year time frame, however, a high number of the animal species that would have been found in Iowa either went extinct or migrated away. That is why excavation sites like the one in Mahaska County are so valuable, Horgen said, so we can try to understand why they left or died.

The mammoth remains in Mahaska County were first discovered in 2010, when a farmer was merely enjoying a walk with his son when the two noticed a strange item poking out of a river bank. That item turned out to be the femur bone from a mammoth’s leg, and the farmer quickly contacted the University of Iowa to share his findings.

From just poking around in the area where he found the femur, the farmer was able to uncover many more bones of all different sizes, Horgen said, which was a good sign because that told the experts the site hadn’t been disturbed.

The team performed soil coring and site mapping around the site to see what was under the surface of the ground in early 2012, then in June 2012 the actual excavation started.

Thanks to a backhoe provided by Titan Machinery and enough volunteers that they eventually had to make a waiting list, the excavations started and provided results almost right away. Soon the team had uncovered most of one leg, a shoulder blade and several other bones.

After just a month of investigating the site, the team was able to find another shoulder blade, but it was determined to be from a separate mammoth. Then, they found a skeleton in August 2012 with a tooth still imbedded in the jaw, a mostly in-tact tusk in September 2012 and a second tusk in November 2012. Now, it is believed that the site has remains from at least four different mammoths, Horgen said.

The excavation team will be heading back to the site this year with possibly a different area to look in. During her presentation, Horgen outlined a piece of the site where they believe more bones could be, and this year’s focus will be a little more on that area. Once we are able to get out of the current ice age, the team will be heading back out to try and uncover more mammoth remains.

As for the bones that have already been taken from the site, Horgen said they belong to the farmer who owns the land. As of right now she said the farmer is hoping to keep the bones in Mahaska County, and there will be an announcement before the next excavation starts about where they will be taken.

— To see reporter Josh Vardaman's Twitter feed, go to @CourierJosh