Polar bears just might outlive us all
On January 24, 2004, in the frigid moonscape of an Arctic winter, wildlife biologist Steven Amstrup rode in a helicopter flying low over the ice. Using an infrared heat detector, he hoped to find polar bears in their dens. When the gun recorded a hit, Amstrup circled around for a closer look. What confronted him was something he had never seen in 34 years of research. The mouth of the den was open, and a smear of bright-red blood stretched away for more than 200 feet. At the end of a long drag trail in the ice lay the still-warm body of a female polar bear. The air temperature was 20 degrees below zero; this bear could not have been dead for more than 12 hours.
Polar bears do not have enemies. A male can weigh 1,500 pounds, with paws a foot wide and savage teeth. They are the unchallenged master predators in the harshest environment on Earth. A full-grown bear slaughtered in her den is far outside the ordinary.