During long periods of the Earth's history, large areas of land have been covered by ice. As temperature fell, sheets of ice upto 200m thick spread across land and sea. The last of these ice ages had a dramatic effect on human and animal life.
The earliest ice age occurred some 2300 million years ago. Geological evidence shows that succeeding ice ages lasted between 20 and 50 million years. As the climate cooled, glaciers formed at the North and South poles. The ice advanced and retreated in waves, known as glaciations. The most recent ice age entered its coldest period about 22000 years ago, when ice sheets covered much of North America and northern Eurasia. As the seas froze, the sea level fell by over 100 m in places, exposing bridges of land between land masses. The Bering Strait between Siberia and Alaska for example became dry land, allowing animals such as mammoths and deer to move between Asia and North America. After them came human hunters, the first humans to colonize North America. Camels and horses moved from the Americas into Asia. When the climate warmed, the ice melted, sea level rose, and this and other land bridges disappeared.
Conditions were extremely harsh for the people lived near the ice sheets. Woolly mammoths were a valuable source of meat, skin for clothes and bones for weapons and carvings. Men hunted in groups, driving the mammoths up against cliff-faces so they could close in for the kill. They attacked with sharp weapons and spears made of flint and wood, and large stones. One mammoth provided enough meat to survive many months. Leftovers were stored in holes dug in the frozen ground. Bones and tusks made a framework for huts, covered with hides and turf.
The last ice age reaches its coldest point around 18000 years ago. The Bering Strait floods over again as the ice melts and sea levels rise. Around 12000 years ago in Europe, glaciers retreat and the ice age ends.
The earliest ice age occurred some 2300 million years ago. Geological evidence shows that succeeding ice ages lasted between 20 and 50 million years. As the climate cooled, glaciers formed at the North and South poles. The ice advanced and retreated in waves, known as glaciations. The most recent ice age entered its coldest period about 22000 years ago, when ice sheets covered much of North America and northern Eurasia. As the seas froze, the sea level fell by over 100 m in places, exposing bridges of land between land masses. The Bering Strait between Siberia and Alaska for example became dry land, allowing animals such as mammoths and deer to move between Asia and North America. After them came human hunters, the first humans to colonize North America. Camels and horses moved from the Americas into Asia. When the climate warmed, the ice melted, sea level rose, and this and other land bridges disappeared.
Conditions were extremely harsh for the people lived near the ice sheets. Woolly mammoths were a valuable source of meat, skin for clothes and bones for weapons and carvings. Men hunted in groups, driving the mammoths up against cliff-faces so they could close in for the kill. They attacked with sharp weapons and spears made of flint and wood, and large stones. One mammoth provided enough meat to survive many months. Leftovers were stored in holes dug in the frozen ground. Bones and tusks made a framework for huts, covered with hides and turf.
The last ice age reaches its coldest point around 18000 years ago. The Bering Strait floods over again as the ice melts and sea levels rise. Around 12000 years ago in Europe, glaciers retreat and the ice age ends.
