By Meghan Rosen
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Parents trying to soothe a fussy infant might want to invest in a sling to carry their kid.
In human infants and mouse pups, bumping along in their mothers’ arms (or mouths) acts as the ultimate pacifier: crying stops, fidgety bodies go still and racing hearts thump more slowly, researchers report April 18 in Current Biology.
The calm may do more than save parents’ sanity. Carrying lulls mammalian babies into a trance that may improve their chances of survival, the study’s authors suggest. Lugging around wriggling banshees is tough work; mouse mothers on the move fare better with babies that relaxed when carried.
“The idea makes sense,” says pediatrician John Harrington of Eastern Virginia Medical School in Norfolk, who was not involved with the research. “If you’re running away from a predator, you’d want your child huddled against your chest and quiet.”