Sea Levels Plunge; Bering Land Bridge Opens
the Ice Age peaked, so much water was trapped as ice on land
that sea levels dropped by 350 feet. Large areas that are
now underwater were dry land. The Florida Peninsula was twice
as big as it is now. Land bridges were exposed between Alaska
and Siberia (the Bering Land Bridge), and between Britain
Megafauna Thrive in Cold
South of the great ice sheets, big animals (called megafauna)
were plentiful. Giant beavers were as big as black bears,
black bears were as big as grizzlies, and grizzlies were dwarfed
by the short-faced bear. The giant beaver, short-faced bear
and many other megafauna went extinct at the end of the Ice
SHEETS COVER NORTHERN HEMISPHERE
the Ice Age peaked some 21,000 years ago, giant glaciers at
least a mile thick covered much of North America and Europe.
Ice sheets were also present in Antarctica, Greenland, and
Asia. Almost one-third of the present land surface of Earth
was covered by ice.
Huge Lake Covers Western Utah
Salt Lake is actually just a small remnant of a much larger
lake, called Lake Bonneville, that covered what is now Salt
Lake City and much of western Utah. Evidence of the ancient
shoreline can be seen in the foothills above Salt Lake City.
The giant lake was the result of higher precipitation in the
area during the Ice Age.
Cold Wave Envelops the World
the coldest part of the Ice Age, much of Earth experienced
moderate cooling, but some areas were dramatically colder
than they are today. Temperatures over the main North American
ice sheet, for example, were up to 45 degrees Fahrenheit (26
degrees Celsius) colder than they are now.
North America Resembles African Savanna
grazing on the Colorado plains
the Ice Age, relatives of modern African animalscheetahs,
lions, camels, zebras, and elephantslived in North America,
earning it the nickname Cold Serengeti. Scientists
think that some of these animals, like cheetahs and zebras,
may have evolved first in North America and then spread to
other parts of the world via land bridges.