Ardi images from Science, Oct. 2, 2009
Very recently, a treasure trove of fossils of a new species of human ancestor was discovered in East Africa. Now known as Ardipithicus ramidus, or Ardi, this 4.4 million year old direct ancestor of ours has refined and deepened our understanding of the prehistory of health.
It is now even clearer that by then our ancestors were already omnivores because it gave them an advantage over other primate species. Their ability to walk upright as well as climb gracefully enabled them to eat a diet that varied throughout the year: fruits when they were available, insects and small animals when they could catch them, and even the few seasonal grains of grass seed before they were snatched up by insects or washed away by rain. Our ancestors set out even earlier than we suspected on an evolutionary path very different from that which led to chimps and apes.
During close examination of the fossil skeleton, it became clear that among other maladies, Ardi survived a deep infection in a foot bone, one that we would now treat with 3 months of intravenous antibiotics! Those were some hardy soles.
We can even infer that by this distant date they were a more cooperative, less combative species than are modern chimps and apes. It may very well be that pair bonding—that is, the typical human team of a single man and woman raising children–goes a whole lot further back than we previously thought.
This opens a vast new perspective on the origins and development of human intelligence, language and behavior. The males and females in Ardi’s tribe were very close in size. Cooperation was key. Effective parents were those who maximized care of a few offspring. Human couples seem to have been working together on this for a long time. Language, rather than emerging to make it easier to hunt or make war, may have developed to discuss what to do about the kids and who was going to clean the nest.