Your body is always adjusting — narrowing vessels, raising tiny hairs, sending blood toward the skin or pulling it deep inside — all to keep a narrow internal temperature that has suited warm-blooded life for millions of years. This episode drifts through the quiet sensations of warmth and chill, the biology of shivering and sweating, the behavioral rituals humans have developed to stay comfortable, and the surprising strategies other species use to navigate heat and cold, from panting dogs to huddle-rotating penguins on the Antarctic ice.

This episode includes AI-generated content.