Monkey motherese. Why do female rhesus macaques freak out over babies? By Mark Peters for Babble’s parenting dictionary.

Every time I flip open a science magazine or Google “monkey,” there’s another example of humanish behavior by non-humans: Some monkeys pay for sex. Others do math. Chimps not only use tools, but make spears. Soon, we may have to face the sad truth that fantasy football and lawn-gnome-having are the only proclivities humans don’t share with some other primate-come-lately. 

Last year, some of these monkeys-do-it-too stories were written about female rhesus macaques, who apparently were found to use a form of baby talk (or motherese) with infants. But motherese is a key element in the mega-complex acquisition of human language, and the macaque’s vocalizations are hardly equivalent to our advice columns and tragic plays. So what did the “Female monkeys use baby talk” headlines really mean?

To find out, I visited one of the researchers, Jessica Whitham, a Postdoctoral Researcher at the Endocrinology Lab of Illinois’ sprawling, ginormous Brookfield Zoo. For Whitham’s colleagues, an animal’s poop is a rich brown window to their hormonal state, allowing noninvasive monitoring for stress, disease, and reproductive state. Unlike her poop-pondering colleagues, Whitham’s specialty is naturalistic observation, which she did on Cayo Santiago, an island just off the coast of Puerto Rico where the female-macaque study was conducted with fellow researchers Dr. Melissa Gerald and Dr. Dario Maestripieri.

Here’s the truth about googoo-gaga and oohooh-ah-ah: It’s going waaaaay overboard to say that macaque grunting and girneying are monkey motherese. But it is safe to say this: macaque females go full-blown apeshit when they see other mothers’ infants.

Though Whitham’s study discusses grunts too, the girneys – which are nasally, melodic, and whine-like – are far more female-and-infant-centric. Whitham says, “I didn’t hear any adult males girney – though I did hear some adolescent males.” Actually, Whitham didn’t hear much of anything during the “no-infants period” (which lasts half the year).

But once some babies arrived, Whitham experienced an explosion of sound and activity: the females were girneying enthusiastically, grunting more often, wagging their tails, and scratching themselves – all signs of excitement. And it doesn’t take much to get a she-macaque going: A baby moving, a baby fussing, or a baby breaking away from mom would inspire girneys and bedlam. Young or old, mothers or not, these macaques did everything but start a blog about the babies they saw.

Interestingly, girneys are never directed at a macaque’s own baby. For macaques, the girneys are a product of surprise and stimulation when they see someone else’s baby, and their own bundle of monkey joy just doesn’t have the same novelty. Past research had suggested the girneys might be a way of communicating to other moms, “Hey, we’re good, I am no threat to your baby.” But Whitham cautions that there’s just no evidence for it. In fact, lots of times girneying will be followed up with – well, with nothing at all, which contradicts the theory that the girney-er is offering an acoustic peace pipe.

What’s clear is that the infant-beholders are freaking excited, and if their behavior is truly like anything in human language, it might be like our exclamations. In other words, a girney might be more “holy crap!” than “cootchy-coo.”

It’s hard to say what effect, if any, the girneys are having on the infants. Since the study focused on she-monkeys alone, the responses of the babies didn’t receive a lot of attention – except from those girney-making, tail-wagging, self-scratching female monkeys, who seem to love babies as much as their human counterparts.

Photo Courtesy of Amanda Accamando

Article Posted 9 years Ago

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