ice age

The circle, named Kostenki 11, was about 40 feet in diameter with no obvious entrance.

The Yarrabubba impact crater in Western Australia is the oldest in the world.

The 330-foot-long structure was created with boulders from a river over a mile away.

The latest known fossils belonging to extinct human species dated to between 117,000 and 108,000 ago.

Researchers find first direct evidence of a "glacial oxygen pump," which they say extended an essential lifeline to the simple life forms that inhabited the Earth at the time.

Archaeobotanists at the University of Glasgow in Scotland have identified more than 75 species of plant frozen alongside Ötzi.

The Pliocene epoch was a paradise for primates. But that ended 2.6 million years as ice sheets started to expand.

Short-faced kangaroos are an entirely extinct group of marsupial herbivores that arose during the Miocene Epoch—around 23 to 5.3 million years ago—and diversified prolifically during Australia's Ice Age.

The trees in the forest would have been about 10 feet tall and resembled palm trees.

Researchers are probing the forest to see if humans ever lived there.

The collision triggers a chemical reaction that causes carbon dioxide to be sucked from the atmosphere.

The formations were "sculpted by 320 million years of ice, wind, and the movement of entire continents," the National Trust said.

These rock formations help to support the idea of a rapid Earth freeze over 700 million years ago.

Dried meat may have offered a long-lasting source of food in a changing rainforest.

If a gene conferred a survival advantage, people with the mutation would have more offspring and the mutation would become more common in subsequent generations.

Scientists think the genetic mutation behind these teeth protected babies against an intense lack of sunlight.

A fossil skull was 20 percent bigger than even those of the largest modern lions in Africa.

The research team came to their hypothesis after analyzing rocks, lakes, and glaciers.

"This is sort of a dark archaeology, where we benefit from climate change that's making this ice melt."

New evidence reveals a previously unrecorded indigenous population and poses a major challenge to existing theories about the earliest Americans.

In a new review of the evidence, half a dozen prominent anthropologists have thrown their weight behind "the kelp highway hypothesis."

At the time, volcanoes in Iceland were erupting 50 times more often than today.

Western spotted skunks do handstands to make themselves appear more threatening.

Melting glaciers turning land to bog was behind widespread extinctions of animals like the giant sloth and woolly mammoth between 15,000 and 11,000 years ago.

The find refutes earlier ideas about humanity's ability to adapt to altitude.