Giant camels used to roam what’s now Los Angeles. If you visit the city’s La Brea asphalt seeps, you can see their bones, ...

Today, sloths are slow-moving, tree-dwelling creatures that live in Central and South America and can grow up to 2.5 feet long. Thousands of years ago, however, some sloths walked along the ground, ...

Cold-adapted animals started to evolve 2.6 million years ago when the permanent ice at the poles became more prevalent. There followed a time when the continental ice sheets expanded and contracted ...