Learn About the Mammoth
This page contains the text and images from all the topics on
the "Learn" page, including The Ice Age, Paleo-Indians, Des Moines 16,000
Years Ago, How Do You Make a Mammoth?
The Ice Age
The Pleistocene, or Ice Age, began over 2.5 million years ago and ended a short 10,000 years ago. During this time, numerous ice sheets formed and moved south from Canada into the United States. Periodically the climate warmed and the glaciers receded, only to form and surge south again.
Why was there an Ice Age?
Large land masses near the poles created a surface upon which thick ice could form.
The formation of mountain ranges caused major climatic change by shifting global circulation patterns.
Decrease in atmospheric carbon dioxide reduces the insulating effect of the Earth's atmosphere, resulting in heat loss.
Changes in the position of the North Pole and the Earth's tilt and orbit around the sun affect how much solar radiation it received.
The Last Ice Age
Links to the Iowa Department of Natural Resources' Geological Survey:
Geology of Iowa: Iowa's Earth History Shaped by Ice, Wind, Rivers, and Ancient
Landscape Features of Iowa
Linked Depressions on the Des Moines Lobe
Glacier Landmarks Trail: Iowa's Heritage of Ice
Glacial Boulders in Iowa
They Came to North America
There was no single event or condition that allowed for human arrival and settlement in North America. Humans probably arrived here in small groups, and families soon spread across all of North America.
How Did They Get Here?
The Ice-Free Corridor:
Sea Coast Migration:
The Atlantic Route:
Evidence of Paleo-Indian Culture
The name Paleo-Indian refers to the earliest human inhabitants of North America. We know about them because the chipped-stone tools they made have been found on the surface of the land and from ancient campsites and butchering sites across the continent. Paleo-Indians were big-game hunters who hunted mammoths and giant bison.
This was a time of change in the environment. The climate warmed and the last glacier melted, or "retreated." Vegetation changed too, and the great Pleistocene megafauna (animals larger than 100 pounds) became extinct. With these environmental changes came changes in how humans lived and their technology—how they made and used things. Archeologists identify early people by their technologies, because the traditions of how they made and used things can be traced over periods of time.
Early Paleo-Indian Clovis
Throwing spears with atlatls (spear-throwing sticks) were probably also used during this time.
Evidence of the Folsom Tradition is found across North America. Although no butchering site with Folsom points have been found in Iowa, numerous Folsom points have been collected on the surface, especially in southwestern Iowa.
Atlatl and Spear
When the arm moves to throw the spear, the arc is increased by the length of the atlatl and imparts more energy to the spear. Experienced throwers can increase their force by two and a half times. With practice, a spear will travel more than 100 yards.
Des Moines 16,000 Years Ago
Des Moines 16,000 years ago was a place of contrasts. At times, the ice front of the Des Moines Lobe surged to the north edge of the Raccoon River Valley and then retreated. The ice stood hundreds of feet high. Sediment choked the Raccoon River, backing up the water and splitting the channel into interlacing braids. At other times the volume of melt waters increased and the current was deep, fast, and abrasive.
This area was a mix of grasslands and forests of spruce, aspen, and oak. Stretching north of Des Moines, in areas where the ice had melted, marshes and muskeg (or bogs) were common. This environment supported a variety of herbivores.
Fossils from the time reveal that the Des Moines region was home to mammoth, mastodon, giant ground sloth, musk ox, a variety of bison, and elk. We do not know for certain if humans walked the Raccoon River Valley at this time, but they may have. We do know that soon they would be in Iowa and surrounding states, hunting the mammoth, mastodon, and other game.
Within a few centuries, the temperatures warmed and the ice melted for the last time. New forests filled the river valleys, prairies stretched out to the west and south, and marshlands continued to the north. The subtle changes brought great change to the inhabitants—extinction for some, and opportunity for others.
How Do You Make a Mammoth?
The life-size cast of the Hebior mammoth was produced by PAST: Prehistoric Animal Structures, Inc., of East Coulee, Alberta, Canada. The molds for the cast were made from the original fossilized skeleton discovered in 1994 on the Hebior farm near Lake Michigan. Because the Hebior mammoth was 90 percent complete, some missing or damaged bones had to be created.
Candid shots show step by step how the skeleton was made and moved, from Canada to our museum.
1. The molds are "painted" with layers of fiberglass
cloth and resin. These sections of the lower jaw and a tusk and lower jaw await
the completion of additional parts before assembly.
2. Two leg bones are mounted together with a steel armature. The enormous size
of a mammoth becomes evident.
3. Freshly painted to look like a bone, the femur is placed into position in
the hip socket.
4. To test that all parts fit together properly, the skeleton is assembled.
Then the mammoth is then taken apart for shipping and packed carefully into crates.
Inside the crates, foam layers protect the skeletal segments.
5. In late November 2003, the skeleton arrives at the State Historical Society
of Iowa in Des Moines.
6. Museum staff unload the five large crates and count the individual segments
of the skeleton.
7. The backbone is readied for installation.
8. Museum staff lift the skull out of its foam protection and move it into
9. The segmented tail is lifted into position.
10. Finally, the last tusk is guided into place in the left alveoli.
11. The test assembly of the mammoth is now complete. Everything fits together
perfectly. Final measurements can now be taken so that the casework can be designed
and built for the exhibit.
© State Historical Society of Iowa