Physicists can use bright, hot lasers to slow atoms down so much that they measure -459 degrees Fahrenheit.
Scientists have worked out a new way to scan beneath the ground for footprints – and it's revealing traces of an ancient world.
Sloths love Cecropia trees. But a new study shows they may sometimes desert their favourite for other species.
How we discovered ancient footprints of early human hunters and their megafauna prey.
Sloths have been moving slowly for 64m years.