Around 15,000 years ago, North American was home to a wide menagerie of giant mammals - mammoths and mastodons, giant ground sloths, camels, short-faced bears, American lions, dire wolves, and more. But by 10,000 years ago, these "megafauna" had been wiped out. Thirty-four entire genera went extinct, including every species that weighed over a tonne, leaving the bison as the continent's largest animal.
In trying to explain these extinctions, the scientific prosecution has examined suspects including early human hunters, climate change and even a meteor strike. But cracking the case has proved difficult, because most of these events happened at roughly the same time. To sort out this muddled chronology, Jacquelyn Gill has approached the problem from a fresh angle. Her team have tried to understand the final days of these giant beasts by studying a tiny organism, small enough to be dwarfed by their dung - a fungus called ...