The chimpanzee war
February 11, 2011 2 Comments
So today 12 February 2011 we want to celebrate the 202° birthday of the genius of Darwin. For this Special day our blog participate to the Carnival of Biodiversity, an initiative promoted by Livio Leoni, Marco Ferrari, Lisa Signorile. Today all the blogs attending this initiative will publish a post dealing about evolution with the title: “Biodiversity and adaptation: the constant competition for food and space”. All the post, including ours, will be listed with a review on the blog Leucophaea (Marco Ferrari) at this page. So enjoy the reading!
The chimpanzee war
Competition between species, between members of the same species and, as Richard Dawkins would say, between genes, is one of the major “driving forces” of evolution. Individuals developing a new feature (due to random mutation) with competitive advantages for survival and reproduction will pass this information on to the offspring and, as such, a small evolutionary step occurs. The competition can be on different levels: competition for food, for female, for space and in the case of Homo sapiens sapiens also for money and power. In the so called “superior animals” (name refers to their elevated structural complexity) adaptation does not only include physical but also behavioral adaptation. Behavior plays an important role in the game for survival. An example would be fear that pups usually show which protects them from being seen and caught by predators. Furthermore, altruism that parents show for their offspring is important for survival. On the other end of the spectrum there is aggression: within the same species, aggressive behavior may be important when fighting for a female or for food. In this perspective, the history of the Homo sapiens sapiens is full of violence and the more aggressions are organized the more deadly and devastating the final outcome is: holocaust and global war. However, anthropologist Christopher Boehm hypothesizes that the identification and suppression of intra-species violence provided the basis for a human moral system and human behavior which gives man a competitive advantage (Boem, Journal of Consciousness Studies, Volume 7, Numbers 1-2, 2000, pp. 79-101 and Boehm Harvard University Press,1999, “Hierarchy in the forest: the evolution of egalitarian behavior.”). This hypothesis is supported by human-chimpanzee comparative studies by Richard W. Wrangham, Michael L. Wilson and Martin N. Muller (Primates, 2006) in which they explored the behavior of chimpanzees with particular emphasis on the rate of intra-species aggression between members of the same or different communities. They calculated that Chimpanzees have a rate of aggression similar to the first hunter-gatherer societies but a 2/3 folds higher aggression when compared with modern humans. These data partially support Boehms hypothesis: the reduction of violence between members of the same species allows community to form and be in competitive advantages respect single individuals. Although humans show a reduced aggression between members of the same species, they are able of coalitional aggression to other groups for the survival of their own group: this is what we call war. Do our closest relatives make “war”? A 10 years study in the Ngogo Kibale National Park, Uganda (where the Homo sapiens sapiens is involved in a intra-species inter-ethnic devastating war) by the naturalists John C. Mitani, David P. Watts, and Sylvia J. Amsler ( Current biology, Volume 20, Issue 12, 2010) showed that Chimpanzees are able to make lethal coalitional attacks on members of other groups for years (like battles) to finally occupy the region of the other groups (they basically win the “war”). Although the reasons for this kind of war are not entirely understood: “It is not sure whether the “coalitional attacks by Ngogo males may lead to new females joining their community” but all the evidences suggest that “By acquiring new territory through lethal coalitionaal attacks, male chimpanzees improve the feeding success of individuals in their own community, which in turn can lead to increased female reproduction”. From an evolutionary point of view this is particularly relevant.”
Although aggression within the same group is a competitive disadvantage for the formation of a community (which, in general, represents a competitive evolutionary advantage for many “superior animals” such as wolves, penguins, but also for insects like ants and bees) inter-group aggression seems to be a common competitive evolutionary trait human beings and chimpanzees have in common.
In conclusion, these data suggest that aggression is something destructive and creative at the same time, creative when it is addressed externally (against other groups, other species etc.), destructive when it is infiltrates a community. Of course , externally directed aggression is destructive for the others and internal aggression is creative for a new group taking over the power but from the point of view of an organism-like community, this conclusion should be right, albeit very general.