At the height of their success woolly mammoths dominated most of Eurasia and about half of North America. The most accurate map of this range ever produced has been released, as part of a study of the conditions in which mammoths could live, and what barriers they were able to cross to get there.
The woolly mammoth, Mammuthus primigenius thrived under Ice Age conditions, with a range far more expansive than their modern pachyderm relatives. "The recent research findings show that during the last Ice Age, mammoths were the most widely distributed large mammals, thus rightfully serving as a flagship species of the glacial era," said Ralf-Dietrich Kahlke, of the Senckenberg Research Station, in a statement.
In total, mammoths occupied more than 33 million square kilometers (13 million square miles), an area larger than Africa, and Kahlke says this is a minimum. In Eurasia they roamed from Portugal to as far east as Korea and Japan, and in North America they stretched right across eastern Canada and the American Midwest, as well as taking in considerable territory that has now been claimed by rising oceans.
Nevertheless there was some territory mammoths could not conquer. Africa, Central America and South and South East Asia were predictably too warm for the shaggy coated beasts, but there were other obstacles as well. In Quarternary International Kahlke reported that “High mountain chains with no passible valleys were another very effective barrier to migration. From the distribution of finds this is particularly evident in the Pyrenees area, the Crimea mountain range and the Greater Caucasus.”
Undeterred by snow or wind, mammoths managed to migrate high on the slopes of these ranges, but were not built for the climbing required to reach or cross the peaks, often leaving territory south of a range mammoth-free. It seems mammoths only reached Spain and Portugal by migrating through territory that is now underwater, since they couldn’t cross the Pyrenees.
Similarly, glaciers and deserts blocked their paths at various points in time, although these obstacles often retreated or shifted in the face of changing climatic conditions, opening up new territory for the giant beasts.
The mammoth's greatest range. Arrows represent obstacles, they could not cross: ice sheets (A), high mountains (B) deserts and semi-deserts (C) and open water that never froze over (D).Credit: Kahlke/Quarternary International.
The map is based on the location and age of mammoth remains and an identification of areas whose climatic and geographic conditions at the time were similar. "Even sites under water, off the North American Atlantic shore and the North Sea, were taken into account,” Kahlke said in the statement, "Such detailed knowledge regarding the distribution area is not even available for many species of animals alive today."
As the world warmed, mammoths retreated into the more limited areas that remained suitable for them, including Wrangel Island, Russia, where mammoths survived until 4,300 years ago.
The only other large animal that had a comparable range during the era was the ice-age bison, Bison priscus. However, its range varied in response to environmental factors that mammoths were more tolerable of.