Ice-age animals live on in Eurasian mountain range

IT’S the land that time forgot. Not only have conditions in the Altai-Sayan region in central Asia barely changed since the last ice age, but the mix of mammals that lives there is also almost the same.

Věra Pavelková Řičánková and colleagues at the University of South Bohemia in České Budějovice, Czech Republic, compiled lists of mammals living at 14 sites across Eurasia. They compared them with mammals that lived at seven Eurasian sites during the last glacial period 35,000 to 12,000 years ago.

The team discovered that the combination of mammals found together in the Altai and Sayan mountains of western Mongolia and southern Russia – such as horses, reindeer, saiga antelopes and wolverines – is similar to the ancient glacial communities. There are a few obvious differences, however, such as the lack of mammoths.

These animals do not normally live together anymore, says Pavelková Řičánková. She says the Altai-Sayan is one of the last places on Earth to retain an ice age fauna (PLoS One, doi.org/q2n).

“You’ve basically got a really good modern analogue for the Pleistocene communities,” says John Stewart of the University of Bournemouth, UK.

The Altai-Sayan has not been fully explored, so could hold more surprises. In 2010, snails thought to have died out when the ice melted were found alive there (Journal of Biogeography, doi.org/d4vn4n).

The cold, arid climate is key to the animal community, says Pavel Tarasov of the Free University of Berlin, Germany. The last ice age had a similarly dry climate, so Eurasia was surprisingly free from snow. Grasses flourished, helping feed the many herbivores.

However, there is a better model for conditions in northern Eurasia, says Tarasov. Wrangel, a small island in the Arctic Ocean, retains the plant community of that time. And the last mammoths lived on Wrangel, vanishing just 4000 years ago.

The Altai-Sayan may also have been vital for humanity’s success. The mountains are home to Denisova cave, famous for the 2010 discovery of 50,000-year-old fossils of a new kind of human, the Denisovans. Since then, Neanderthal bones, and tools crafted by Homo sapiens have also been found in the cave. This makes it the only place where we know all three hominins lived.

That may be no coincidence, says Pavelková Řičánková. Conditions in the Altai-Sayan are fairly stable, so ancient humans may have taken refuge there and lived off the diverse game species.

“It looks increasingly like the east [of Eurasia] may have been a refugium,” agrees Stewart.

When the ice age ended, the Altai people left the mountains and spread far and wide. Recent genetic evidence suggests that the first Americans can trace their ancestry to the Altai-Sayan (American Journal of Human Genetics, doi.org/fxq8gx).