Although the cutting edge of parenting advice evolves minute by minute, some principles never change: cuddles are good; head trauma is bad; and swaddling your little one is a must. We’ve been wrapping our young since the Paleolithic, and thousands of years from now, I’m sure that the survivors of the zombie apocalypse will still be swaddling their traumatized infants.
Babies need blankets because—please forgive the technical jargon—babies are small.
Once again, ignore the details: the tiny toothless mouth, the eensy wiggling toes, the small bald head that smells so amazing. Think of a baby the way you’d think of any organism: as a homogenous bundle of chemical reactions. Every activity of the body is built on such reactions; in some sense, the reactions are the creature. That’s why animals are so temperature-sensitive: Too cold, and the reactions slow to a halt; too hot, and some chemicals deform, making key reactions impossible. You’ve got to keep a close eye on the thermostat.
Heat is created by reactions in each cell (i.e., in the interior). And heat is lost through the skin (i.e., at the surface). This creates a familiar tug-of-war: interior vs. surface.
Bigger animals, being more interior-heavy, will have an easy time keeping warm. Smaller ones, being surface-heavy, will struggle. That’s why you’re most vulnerable to cold in your surface-heavy extremities: fingers, toes, and ears. This also explains why cold climates support only big mammals: polar bears, seals, yaks, moose, mooses, meeses, and (depending on your zoology professor) the Sasquatch. A surface-heavy mouse wouldn’t stand a chance in the Arctic. Even at moderate latitudes, mice cope with heat loss by eating a quarter of their body weight in food each day.
A baby isn’t a mouse, but it’s definitely not a yak. Its tiny body expends heat like governments spend money. And to stifle that heat loss, there’s no cuddlier option than a blankie.
