1.6 Million Years Ago - Present
During the Pleistocene and Holocene Ice Age of the Quaternary Period, known as the age of humans, glaciers covered Illinois. Glaciers worldwide stored so much water that the Bering Strait was above sea level, enabling humans to migrate from Asia to North America. Ancient remains date human activity in North America to more than 15,000 years ago. Evidence of human habitation in Illinois extends more than 12,000 years to the nomadic Paleoindians, who hunted megafauna, giant animals, with long flaked stone lance points. As the Ice Age glaciers retreated northward, the climate warmed and Paleoindians expanded across North America. Challenged by a changing environment and human predation, many large mammals became extinct by the end of the Pleistocene Epoch, including mammoths, mastodons, giant ground sloths, saber-toothed cats, and dire wolves.