I'm supercool and control my own body clock

摘要

Not content with being the world's coolest mammal, the Arctic ground squirrel now has another accolade: it is the first mammal known to switch its body clock on and off. The constant light of the Arctic summer and constant darkness of the winter make it difficult to tune circadian clocks to environmental cues. As a result, many Arctic species, such as reindeer, lack circadian rhythms entirely.