Bonobo photo: By Psych USD (CC BY-SA 3.0)
Bonobo | via Psych USD | CC BY-SA 3.0

About a year ago I watched a hilarious segment on ”60 minutes” about Italian males. More specifically, about their shameless attachment to their mothers. And I am not talking about kids. They interviewed strapping young guys, middle-aged men, even gray-haired executives who felt just fine in mamma’s home, thank you very much. They just couldn’t think of a reason to move out. And how did the opposite sex regard this Oedipal arrangement?  Some didn’t mind, some thought it is really cute and hoped their son would stay with them – it was sort of a biomarker of a loving potential husband. Except, the potential mate wasn’t so inclined at all. Strange, I thought. Is it merely a cultural quirk of Italians, or is there a more “biological” explanation?


When in doubt, watch what apes do

The two primates that are evolutionarily closest to Homo sapiens (that’s us), are the chimpanzees (Pan troglodytes) and the bonobos  (Pan paniscus). The latter are fascinating creatures, and in my opinion, deserve close study. Their social interactions are exemplary and should be adapted and widely adopted.

Bonobos are a famously pacific species. Like the legendary people of Oklahoma,  not a harsh word is heard; even between bonobo troops disagreements are settled by a sort of negotiation. There is one more trait that is worth mentioning: they are totally, wholeheartedly, enthusiastically sexually promiscuous. This is contrary to the behavior of chimpanzees, where the dominant male gets the right of first refusal, and he never refuses! The other males are reduced to a furtive one minute stand when the alpha male is busy with another female or is distracted for some other reason.  If they get caught –they may face banishment from the troop, which is tantamount to a death sentence. But even the alpha male cannot do as he pleases –the female has to be in heat. If she is not, she will not be receptive and all his chest pounding bravado will be a waste of time and energy.

The female bonobo, on the other hand, is always in the mood. She will enthusiastically participate in sexual trysts any time of day or night, and as many times as possible. Sexual intercourse seems to be pleasurable like it is in humans. Rather than strictly a biological business, sex among the bonobos serves not only for reproduction but as a social lubricant of sorts. Disagreements between a male and a female are smoothed over with a smooch and a quickie. They use sexual activity to reinforce social bonds. In a word, they are sexually liberated; the primate equivalent of our own “flower children”.

But there is always a hitch. The bonobo society is highly hierarchical; the alpha male still gets first dibs. Then comes his second in command, the powerful male who is just biding his time before he gets to be alpha, and so on down the pecking order. So what’s a  horny teenager to do? Call mommy!

In a paper published in the Proceedings of the Royal Society B (8 Sept. 2010), titled  “Mothers matter! Maternal support, dominance status, and mating success in male bonobos (Pan paniscus)” The authors evaluated mating success determinants in male bonobos using data from nine male individuals from a wild population. And lo and behold, in addition to the expected dominance rank, the presence of the mother determined mating success. Thus, once all those macho guys spotted mother they would deferentially make room and allow junior to have a go at it.

We can easily guess why junior would like this arrangement. But what’s in it for her? Elementary, dear reader. It increases the odds that her DNA would be passed on. Isn’t that what natural selection is all about? So why doesn’t the father do it for his son? Because he can do it all by himself, thank you; the mother cannot –so she uses a proxy.


What about the Italians?

If there is an evolutionary advantage to keeping the son at home, it escapes me. Yes, they gave us beautiful operas, and Neapolitan songs (mostly about mamma, by the way), and Leonardo, and Michelangelo, and Mussolini,  and the Vespa scooter. But that’s hardly an advantage from an evolutionary aspect. In fact, those Italian mamma boys are less likely to pass on their DNA.

I am stumped. Any suggestions?


Dov Michaeli, MD, PhD
Dov Michaeli, MD, PhD loves to write about the brain and human behavior as well as translate complicated basic science concepts into entertainment for the rest of us. He was a professor at the University of California San Francisco before leaving to enter the world of biotech. He served as the Chief Medical Officer of biotech companies, including Aphton Corporation. He also founded and served as the CEO of Madah Medica, an early stage biotech company developing products to improve post-surgical pain control. He is now retired and enjoys working out, following the stock market, travelling the world, and, of course, writing for TDWI.


  1. Well, the advantage of keeping her son at home is clear; she has a man to do all the things her husband would have done for her. Maybe, the evolutionary drive to pass on one’s genes, among Italian women, is not as powerful as the need to be protected and cared for in old age.

  2. Italian men are interesting. The mom’s perpetuate it though. I knew one lady who bought an extra place for her son. Then, she’d go to this new place where you’d find her doing all the cleaning, washing of clothes and even cooking for him. Seemed more like a maid than a mother to me. However, she seemed totally fine with this arrangement.

    Now he’s married. She’s still found helping him, but now it’s watching the grand baby.

Comments are closed.