But for bonobos (which are one of my favorite primate groups, by the way), mothers seem to know what's best for their offspring -- especially their sons -- on hierarchical and reproductive levels, according to a new study.
Photo by tim ellis
Male bonobos are philopatric, meaning they stay in their family group upon reaching reproductive maturity; reversely, once females reach their reproductive prime, they leave to find a new group. Since the males stay, their social statuses are largely determined by the ranking of their mothers (who had to establish their dominance on their own). It's no surprise that these higher ranking males -- with higher ranking mommies -- enjoy the perks of having access to more resources and mates.
The study, which was published in the journal Proceedings of the Royal Society B, found a positive correlation between the dominance status of a son (which is usually determined by his mother) and his mating success. They also found that when mom is around, she'll try to give her son a leg up on the competition by blocking or intervening in conflicts when her son and a higher-ranking male are vying for the same female.
Can you say "mother's boy?" Anthropomorphize much?
But one downfall is that the researchers didn't determine whether mothers' efforts actually affected the paternity of any new offspring (they did not genetically test each offspring to see who fathered it). The moms probably increased the likelihood of their sons fathering offspring, but it's not exactly proven yet. I imagine the genetic facet might be dovetailed into a new study -- after all, finding this correlation in paternity would confirm that mum's help mattered in the grand, Darwinian scheme of things.
In a nutshell, I think this study is important for two reasons:
1. Understanding the group dynamics of bonobos, particularly at the reproductive level, will provide researchers and conservationists with the information to create more effective conservation programs. Since bonobos are endangered, a greater understanding of their reproductive and social behavior will benefit the study and management of both wild and captive groups. I suspect the bonobo AZA Species Survival Plan committee will take a look at this research sometime in the near future, especially if the work can be replicated and reported elsewhere.
2. Bonobo matriarchy is intriguing because it's possible that early humans may have behaved similarly. I've always been fascinated with life history theories. The Grandmothering Hypothesis is one of my favorites and suggests that menopause in women may have been evolutionarily advantageous because it allowed older women to make larger investments in their offspring and grand-offspring. It's the idea that reproductive senescence, or the stopping of reproductive cycles, could not only reduce injury or death during birth for older woman and their babies, but also allow the women to ensure their genes survive. Female bonobos, on the other hand, do not experience menopause; in fact, they continue to reproduce until death. And since female bonobos leave the group upon reaching sexual maturity, I'd imagine there's no grandmothering behavior at all. But there's something familiar about this mother advantage in bonobos.
Menopause aside, what if these reproductive strategies employed by bonobo mothers were also used by early humans to bolster the reproductive success of their offspring? What if they still are? Aren't grandmothers and mothers the most outspoken and pushy matchmakers in their children's/grandchildren's lives?
Depends who you ask, I suppose.
The Internet may have filled that niche recently.
What do you think?
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