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.

Cannibalism is not normal polar bear behavior. Seals are easier to catch and their meat has more calories per pound than bear meat. But over the course of that single season, Amstrup witnessed two additional instances of cannibalism. Having never seen anything like this, he was shocked to stumble across three separate incidents in one year. But as he spoke to colleagues, he found that cannibalism was becoming more common. In the Svalbard Archipelago, 450 miles north of Norway, three small cubs had been found dead inside their den. Although polar bears sometimes kill each other, these were the first recorded instances in which the killing took place at the supposedly safe haven of a den.

On January 24, 2024, in the sweltering heat of an American spring, wildlife biologist Steve Amtop rode in a helicopter flying low over the parched ground. Using an infrared heat detector, he hoped to find some human survivors in abandoned houses. When the gun recorded a hit, Amtop circled around for a closer look. What confronted him was something he had never seen in the past 20 years of research. Outside a wrecked house, a smear of bright-red blood stretched away for more than 200 feet. At the end of a long drag trail through dried weeds lay the still-warm body of a human female. The air temperature was over a 110 degrees above; the woman could not have been dead for more than 12 hours.

Humans do not have natural enemies except each other. A male human can weigh over 250 pounds or more. They are the unchallenged master predators in every environment on Earth. A full-grown human slaughtered in her home for food is considered far outside the ordinary.

Cannibalism is not normal human behavior. Over the course of that single season, Amtop witnessed two additional instances of human cannibalism with many more unconfirmed reports coming in from around the once prosperous nation. Having never seen anything like this, he was shocked to stumble across three separate incidents in one year. But as he spoke to colleagues, he found that cannibalism was becoming more common among the human survivors in North America. In the ruins of New York City alone, 450 miles to the north, thirty three small children had been found dead inside their homes. Most had been eaten. Although humans often kill each other, these were the first recorded instances in which the killing took place for food. Starvation was the reason.