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The Surprising Reason Babies Cry at Night

The Surprising Reason Babies Cry at Night

A new study speculates on an interesting reason babies cry at night—it could be because they’re trying to prevent Mom from procreating and giving birth to a sibling. Sneaky!

The research, published in the journal Evolution, Medicine, and Public Health, hypothesizes that whether consciously or unconsciously, babies could be applying a “survival of the fittest” technique, preventing the birth of a new sibling that will compete for food and care from their mother.

“It’s clear that babies can get enough milk even if they sleep through the night,” evolutionary biologist David Haig told NPR. “The waking becomes a different issue. I’m just suggesting that offspring have evolved to use waking up mothers and suckling more intensely to delay the birth of another sibling.” Nursing a child, especially at night, can stop women from resuming ovulation soon after a pregnancy, explains NPR. By keeping Mom too tired to procreate, the baby guarantees that he or she won’t have to share her resources.

Not everyone agrees with Haig—it’s not just the baby who benefits from nighttime feeding, anthropologist Holly Dunsworth tells NPR. “There are so many good juices running through infant and mom,. It’s rewarding beyond the calories and hunger satiation for everyone involved. When you look at it from that perspective, waking up to feed looks more like cooperation than conflict.”

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Read more: Babies, Caregiving, Children, Family, Pregnancy

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12:37AM PDT on May 22, 2014


4:54PM PDT on May 17, 2014

Idon't believe it.

8:53PM PDT on May 15, 2014

Thank you!

6:01AM PDT on May 15, 2014

Have animals so i will sleep well at night without any crying :) !

2:56AM PDT on May 8, 2014

Bravo, Sheila & Kathrynelizabet! Speak out about non-articles and BLUR "journalism". Both of you educated and reasonable. For info -- waste of time. For joy at readers' response -- worth my time to read. Since you are located
opposite sides of USA, I am hopeful about our nation now. Thanks, again.

2:47AM PDT on May 8, 2014

I think this may be a theory that's an evolutionary stab in the dark, so to speak. Really, there are a lot of reasons babies wake in the night and this may be one but any mother knows that a baby could be wet or cold or even have a dream that isn't dreamy. They can't speak so what else would they do for attention than cry or make enough noise for their mothers to comfort them.

4:00AM PDT on May 4, 2014

Thanks for sharing.

8:18PM PDT on May 3, 2014

Thank you!

12:49AM PDT on May 3, 2014

Thank you :)

8:56PM PDT on May 2, 2014


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Disclaimer: The views expressed above are solely those of the author and may not reflect those of
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