Global heating motivated American mastodons to trek north

Shift led to local extinctions and could have important implications for species today

Genetic diversity could shrink as animals venture into new territories because of global heating leaving them vulnerable to extinction, scientists have warned after tracking the impact of climate change on the American mastodon.

Huge, hairy and with a pair of fearsome tusks, mastodons resembled stocky, hirsute elephants. The earliest fossils of American mastodons date to about 3.5-4m years ago with the creatures commonly found in wooded and swampy areas where they browsed on trees and shrubs.