Montana Governor and First Lady's Math and Science Initiative
A Pleistocene Wonderland
Mile Post 321 on US Highway 2, at the Chester Park rest area.
Imagine you are a time traveler and have the opportunity
to visit this area 25,000 years ago. You would recognize
the Rocky Mountains to the west. The igneous and
heavily glaciated Sweetgrass Hills loom on the horizon
far to the north. The last of the great continental glaciers had retreated, leaving behind a hummocky grassland with
ponds, swamps, and erratic boulders. The grasslands support
an abundance of animal life, much of which would be
recognizable as still inhabiting the northern Great Plains
today. However, there would also be many animals that have
long been extinct. Almost all of them would be much larger
and adapted to a colder post-glacial climate.
Great herds of horses, pronghorn antelope, elk, camels, and
giant bison would be a common site on the plains. They milled
around with groups of blond-haired Shasta ground sloths, and
shaggy Musk and Shrub oxen. Columbian mammoths with
long, curving tusks roamed the plains in small groups. Dire and
Gray wolves and short-faced bears followed the herds in search
of easy meals. At 10-feet in length and more than 2,000 pounds,
the bears dwarfed today’s Grizzlies in size and ferocity. Perhaps
the most famous of all Pleistocene predators were the fearsome
saber-toothed cats. Relatively small and compact, the cats may
have ambushed their prey and slashed at them with their 7-inch
long canine teeth. Perhaps even more deadly, however, was
the long-legged American Lion, a killing machine bigger than
the Bengal tiger. Climatic changes, limited food supplies, and,
possibly, over-hunting by paleo-Indians caused many species
once common to the northern Great Plains to become extinct
about 11,000 years ago. The American bison, gray wolf, elk, and
pronghorn antelope are descendants of that primeval ecology.
The Pleistocene Wonderland
