Ice Ages

An ice age is when a lot of the world is covered by thick ice.
It can last for hundreds of years.
Big animals lived in the last ice age.
Some were like hairy elephants with huge curved tusks.
They were woolly mammoths.

An ice age is a period of time when vast sheets of slowly-moving ice cover enormous areas of the earth. The last one reached its peak about 20,000 years ago and is generally called 'The Ice Age' although there have been several times in history when most of the northern hemisphere was covered by masses of ice up to 2 km thick.

An ice age starts when daily temperatures drop by just a few degrees for a long period of time. More snow falls each year but not all of it melts so the snow gets deeper and deeper, and the bottom part turns to ice. The weight of that increases, and spreads out. The ice becomes glaciers that increase and move slowly, picking up rocks and dropping them further on. The ice scrapes the land as it moves.

When there is a long period of time during which there are several periods of ice age, or glaciation, with warmer periods in between, it is called a glacial epoch (say glay-shull ee-pock).

The last ice age started about 90,000 years ago and ended about 10,000 years ago. It was part of a glacial epoch that started 2 million years ago, called the Pleistocene (say play-stoe-seen) Epoch.

During the Pleistocene Epoch some places escaped glaciation because they were too dry and there wasn’t enough snow to form glaciers. Some places were too high to be covered by ice. Other places were further south and the glaciers did not reach them. These areas were places where plants and animals survived and then spread out after the glaciers melted.

There are many fossils today that tell us of the amazing animals that existed during the Pleistocene era. Together, they are known as megafauna, and include animals such as woolly mammoths, mastodons, giant beavers, small horses, ground sloths the size of cows, and sabretooth cats. These became extinct around the end of that era, perhaps because the climate changed rapidly as temperatures rose and the glaciers melted, but also perhaps because of human hunting. Some species survived however and are found today, including wolves, caribou, muskoxen and moose.

Go here to find out more about the last glaciation, known as The Ice Age, and about the animals and plants of the period:

http://www.zoomdinosaurs.com/subjects/mammals/Iceagemammals.shtml

If you use any of this information in your own work acknowledge this source in your bibliography like this:
Sydenham, S. & Thomas, R. Ice Ages [Online] www.kidcyber.com.au [2008]