Adoptive chimp single dads and evolution of altruism
Posted by Dave Bath on 2010-01-28
A recent paper in PLoS "Altruism in Forest Chimpanzees: The Case of Adoption" has a few things to say about costly altruism – adoption of orphans, the socio-economic conditions required for altruism, and raises the questions of why human males aren’t primary caregivers half the time, as half the chimp adopters of unrelated infants were male.
Males managed to give good care, sometimes for years, measured by comparing the development of adopted and non-adopted kids, and were prepared to adopt non-related kids, even those not completely weaned. In a troop that walks often, carrying an unweaned infant on your back (for many months), preparing food, searching for and waiting for an infant, is a significant investment, particularly when the rest of the troop don’t do these things for kids when the kid has a parent, natural or adoptive.
It’s a tough life for the Tai troop compared to other troops. Tais are in an area with more leopards and many diseases such as anthrax and ebola, yet they show much greater altruism than other wild troops who have it easier, and certainly more than captive chimps who enjoy 24/7 valet service from humans.
Empathy and a willingness to go out of one’s way for unrelated unfortunates – mateship in other words – what we deem an Australian characteristic, developed in tougher times, while in today’s relatively luxurious times, getting each single cent of tax for the common wealth from voters is a nigh-impossible task if election campaigns are any guide.
That male Tai chimps will make the investment required to foster unweaned unrelated chimps puts many males in our modern society to shame, especially those humans that are eager to let the wife do the child-rearing, or too ready to ditch wife and kids when a more nubile female becomes available, and even then, play hardball when it comes to child support and property settlements.
Or, is such a paucity of nurturing behaviour by males the product of a sick or merely a sybaritic society, which focuses on the rewards of consumerism, relative status, happy to treat so many of the poor or even destitute as undeserving bludgers?
Or could we go even further, to say that the gender imbalance in child-rearing versus the too-commonly soul-destroying participation in the rat race of employment, so typical of what some call "family values" or "traditional Western values", is actually unnatural, something that has disadvantaged males for generations, deprived them of the joys of nurturing? I reckon so, from my experience as a sole parent, and now a significant carer of my grandson two days a week [update: since early 2010 it is 10 days a fortnight] (I’m the only grandparent who has any contact).
To my mind, the gender imbalance in child-rearing can be seen as unfair, but I reckon it’s the males who are missing opportunities, sometimes kept out by females taking the cream, sometimes, whether through tradition or politics, by pathological attitudes of our society.
The abstract notes that "in recent years, extended altruism towards unrelated group members has been proposed to be a unique characteristic of human societies".
The discussion in the paper ends with the following:
… high predation pressure exerted by these cats seems to have promoted strong within-group solidarity in the form of care for all injured individuals as well as joint coalition defense against the leopards. Once established, this care for the welfare of others seems to have been generalized to new social contexts, including adoption. Any discussions about the evolution of altruism must include the caveat that dissimilar socio-ecological conditions will lead to important population differences in both chimpanzees and humans and we need to remain very careful before making any claims about species differences.
Yes indeed. It is a very useful paper for thinking about the evolution of altruism.
But perhaps it should give us pause, and contemplate the devolution of altruism as well.