Ancestors of both the extinct mammoth and modern elephants originated in equatorial Africa, scientists believe. But mammoths migrated north between 1.2 and two million years ago just as climate change caused temperatures to plunge.
The move is surprising since elephants are not adapted to the cold.
In particular, the blood protein haemoglobin – vital for carrying oxygen around the body – is inhibited at low temperatures.
Scientists investigated whether changes to haemoglobin may have been part of the mammoth’s cold climate secret.
Their hunch was confirmed when they analysed preserved DNA from a 43,000 year-old mammoth whose body had been frozen in ice.