Free Republic

High in the Andes, thousands of meters above sea level, speedy hummingbirds defy near-freezing temperatures. These tiny flyers endure the cold with a counterintuitive trick: They lower their body temperature—sometimes as much as 33°C—for hours at a time, new research suggests. With a metabolic rate roughly 77 times that of an average human, they need to feed nearly continuously.But when it gets too cold or dark to forage, maintaining a normal body temperature is energetically draining. Instead, the small animals can cool their internal temperature by 10°C to 30°C. This slows their metabolism by as much as 95% and protects...

It starts with mumbling and stumbling. Then come violent shivers and then, paradoxically, a false sense of warmth that makes some people strip their clothes off. Eventually, they may curl into a fetal position as their muscles go rigid, their skin goes waxy, and the heart slows down, then stops. Whether two climbers missing on Mount Hood for more than a week are still alive is not clear. But if they are somehow still hanging on in the brutal cold and howling winds, perhaps hunkered down in a snow cave, they may be going through what veteran climbers say is...