(Inside Science) — Perhaps it’s not a coincidence that Valentine’s Day falls at a chilly time of year. In biological terms, social drives like love may be bound up with the need to keep warm.

The same hormone, oxytocin, helps regulate both physical and emotional warmth, increasing body heat and facilitating social bonding. And according to recent research, baby mice deprived of the hormone are less likely to cuddle with other mice or crawl toward heated surfaces.

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