The polar regions are the coldest places on Earth. During the summer, the poles receive 24 hours of sunlight, but during the winter the sun is rarely visible. Animals that inhabit nature’s freezers ...

The largest wolf, a yearling male, was a bully at 70 pounds or so. The smallest, the runt of that year’s litter, was hardly bigger than a throw pillow, her eyes lined in black. A pair of ravens ...