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Martin Surbeck/Kokolopori Bonobo Research

Bonobo ‘helicopter’ moms stand guard while their sons mate

In what may be the bonobo take on a fussy mom giving her son's number to a nice, single woman at the grocery store, female bonobos go to extremes to make sure their sons mate, introducing them to fertile females and even standing guard while the two couple up, according to a new study.

Researchers already knew that mothers of chimpanzees—bonobos’ close evolutionary cousins—help their sons in male-on-male fights for dominance. Yet bonobo females, who get their pick of mates, take things even further. Because a few select, high-ranking males tend to monopolize the mating pool in their matriarchal society, lower-ranking males are essentially forced out.

Not ones to leave their genetic legacies to chance, the mothers of male bonobos bring their sons around to fertile females and introduce them, according to researcher observations in the Democratic Republic of the Congo. The mothers not only used their own rank to help boost their male children's social standing, but also acted as bodyguards during their sons’ mating attempts—and even tried to break up the mating attempts of other males. Overall, males who had a mom around to help were about three times more likely to produce offspring than males without maternal support, the researchers report today in Current Biology.

Curiously, daughters didn’t appear to get such maternal support, possibly because female offspring often disperse and form or join new communities rather than staying close to home. As to why bonobo moms go to such efforts to help their sons, the researchers conclude it’s a rather straightforward way to continue supporting their genetic line without having more offspring of their own.