Breaking the Ice

She’s hot. He’s still cold. Global warming is upending the sex lives of arctic ground squirrels. That’s bad news for food chains

A photo essay by David Kakuktinniq

Mark Brown built a life around the world’s oldest rock. But what if it isn’t the oldest?

Forest fires Trigger a natural Cycle of Destruction and Regeneration. And you can see it for yourself. Here’s what to look for

Is artificial intelligence going too far? We consulted the expert

Wood bison are survivors, making it through disease, habitat loss and more. But as highway traffic grows, cars may be more than they can handle