十万个为什么·科学启蒙30篇（2）

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为什么有些动物冬眠，而另一些则迁徙？

Animals choose hibernation or migration based on their body size, food needs, and habitat.
Small mammals like ground squirrels hibernate because they lose heat too quickly to survive cold winters.
Bears enter a lighter form of dormancy called torpor, lowering metabolism without dropping temperature much.
Birds and whales migrate instead because flying or swimming lets them follow food year-round.
Migration requires huge energy reserves and precise navigation using stars, Earth’s magnetic field, or landmarks.
Hibernators rely on stored fat and slow bodily functions to conserve energy for months.
Some frogs freeze solid in winter and thaw alive in spring thanks to natural antifreeze proteins.
Climate change now disrupts both strategies by shifting seasons and altering food availability.
Scientists track these behaviors with satellite tags and tiny sensors on wild animals.
Both adaptations show how evolution shapes survival in extreme environments.