In sticking with the recent naturalism binge, I figured it’s time for an example of Natural History and the evolution of morality.
It was previously thought, based upon captive chimpanzee studies, that unrelated altruism was exclusively human among the apes. Long term observations of wild chimpanzees (holy crap, it’s natural history) have now cast doubt on this idea. The researchers reference observations of adoption of orphan chimpanzees by both males and females. Of these, the males are the most interesting (9 males performing 10 adoptions): in three cases, the males were older siblings, two were of unknown relationship, and one was the father. It is unusual for chimpanzee males to take a role in caring for offspring. Most of the males “have not been observed to develop long-term bonds with specific females, nor to invest much in their own offspring.” They tested for genetic relatedness in four cases, and of these, three demonstrated the male was unrelated to the orphan. This is best illustrated in one provided example:
Remarkably, all adult males of the East Group that adopted young orphans went a step further by investing in unweaned small infants and carrying them dorsally during travel for many months. Since, Taï chimpanzees walk about 8 km per day on average, this represents a notable investment. Porthos’ adoption of Gia lasted for 17 months, until his death due to Anthrax, and he was seen to carry her even in extremely risky situations, such as during encounters with neighboring communities. Furthermore, some males were seen to share their night nest with their adopted infant. Fredy, the 3rd ranking male of the East Group, adopted Victor, the son of Vanessa, who died from Anthrax in late December 2008, and shared his nest with him every night, carried him on his back for all long travels, and shared the Coula nuts he opened from December 2008 to July 2009. For example, on February 17th, Fredy cracked 196 Coula nuts for 2h05mn and shared pieces of 79% of them. This gives a measure of the altruistic investment made in an unrelated infant.
The researchers go on to conclude that since this form of altruism is not seen in captive populations in which few offspring are orphaned, all are provided with sufficient food, and very little travel is required, altruism may not develop due to the low risk of death. In areas with high mortality from predation and disease, care for every individual of the group may serve as a form of group cohesion and assist in maintaining group size (obviously a defensive benefit when dealing with leopards).
I don’t think this “Changes everything!” I would instead say this “changes nothing.” We just better understand why altruism may not be observed in captive populations, thanks to Natural History (and a little genetics).
Studies such as this go to great lengths in shedding light on human social and cultural evolution and perhaps can give some indication of how, no only of the development of moral codes, but also the development of our social structures originated. It seems naturalism gives us incredible insights into, not only the universe, other organisms, and our planet, but also into our own minds.
Boesch C, Bolé C, Eckhardt N, Boesch H (2010) Altruism in Forest Chimpanzees: The Case of Adoption. PLoS ONE 5(1): e8901.