Biology
Torpor and Daily Energy Conservation in Small Endotherms
Quick fact
Torpor is not the same as hibernation: torpor lasts only hours, while hibernation can last weeks or months. Many small birds and mammals, like hummingbirds and mice, use torpor almost daily to survive cold nights or food shortages.
Why this is interesting
You know that feeling of wanting to curl up and do nothing when you're tired? Some animals do that—but they actually lower their body temperature and slow their metabolism to save energy. Why would a warm-blooded creature risk such a drastic change?