German chronobiologist Till Roenneberg advances some speculative but plausible evolutionary explanations for the existence of night owls. Across cultures, early birds get all the credit for hard work—catching worms, etc.—but according to Roenneberg, the real bacon was likely brought home by night owls. Some of our natural prey is nocturnal, and some of it’s just easier to catch after dark. One reason warm-bloodedness was such a triumph of mammalian evolution is that the ability to regulate our body temperature meant we could function at night, when the air gets cooler—and our cold-blooded predators, competitors, and prey get sluggish. Night-owlishness was a further adaptation, a chance mutation that proved useful for feeding the tribe. I sometimes think about this when I find myself staring into the fridge at 2 a.m.