ADVERTISEMENT
  About the SA Blog Network













Guest Blog

Guest Blog


Commentary invited by editors of Scientific American
Guest Blog HomeAboutContact

My Ancestors Slept Here


Email   PrintPrint



When I, mild-mannered guy, journeyed to wild remote Africa, I made sure my mind was revved up with knowledge of evolution, and my body was revved up with vaccinations of typhoid, yellow fever, hepatitis A, tetanus, polio, meningococcus, and measles.

With the best of romantic intentions, in a small gift box, I had surprised my wife on our 25th wedding anniversary with two blank airplane tickets and pencil. “Write in wherever you want to go in the world,” I offered magnanimously.

I think her scream of happiness punctured my eardrum.

I do not believe, however, that my gut reaction to her choice of the wild jungles of Uganda was the romantic response she was looking for. I said, “Why don’t we just go to the zoo, stare at the hippos, and skip malaria altogether?”

But the best advice I ever heard was “if you can’t get out of it, get into it.” So that’s what I did. I decided to experience Africa in my own way, immersed with a background scientific appreciation for a place that is the bedrock of life, the cradle of evolution, and birth home of humans. I thought of it like going back as an adult to visit the childhood home in which I was born and spent my early toddler years — a place about which I have no conscious memories, but which nonetheless shaped my experience and underlies who I am and where I came from.

Our focus in Uganda was on primates. The last common ancestor of humans and chimpanzees, before the lines diverged, was about 6 million years ago. Few realize that for much of these 6 million years, at least 27 separate human species evolved. Usually more than one human species existed at the same time.

But over time all the other human species went extinct (Neanderthal being just one of many extinct human species), leaving just us, Homo sapiens sapiens, as the sole surviving human species. Chimpanzees and bonobos also survived, and so chimps and bonobos are our closest living relatives. I wanted to encounter, as genuinely as possible, a sense of what our ancestors’ lives were like.

Kibale Forest National Park in Uganda has one of the highest concentrations of primates in the world. We booked the Chimpanzee Habituation Experience through the Uganda Wildlife Federation. Habituation is a process whereby wild animals get used to human presence without altering their natural behavior. Along with an armed scout and a guide, we spent an entire day with a group of chimps, often just a few feet away, immersed in their world.

We saw playing, hoots of greeting, feats of climbing and swinging, submissive and dominant displays among ranked males, snuggling together during naps, making nests in tree branches, eating in fig trees, and patrolling territory. A wild chimp would be hanging upside down on a branch in front of us, while next to us on the ground a chimp would lie on his back and scratch his foot. When they rested, we rested. When they moved, we moved with them.

There was one female in heat, physically evident by her blatantly swollen pink bottom. At one point a male chimp stood behind her to mount. In two seconds — no exaggeration — the act of intimacy had been initiated, consummated, and completed. Two seconds. When he was done, he just sat down and yawned repeatedly.

During the day, this one female in heat had a similarly brief — shall we say efficient? — coital interaction with every adult male in the group. It turns out that when female chimps are in heat, one mating strategy is to have sex with every mature male in the group. Adult male chimps will sometimes kill infants that are not their own genetic offspring. With this mating strategy, any male could be the father. So each of the males accepts a new infant as part of the group.

We saw chimps with expressive faces and eyes, patting each other, touching, angry, playful. I don’t see how one could doubt that we are related to chimps. It is more than just anatomic similarity. Studies have demonstrated that chimps can reason, show symbolic representation, and have a concept of self. Chimps are so closely related to us that humans can receive a blood transfusion from a chimp with the same blood type. And chimps can similarly receive human blood.

Chimps share about 98% of our DNA. That shows our extraordinary proximity from an evolutionary genetic perspective.

Still, the connection only goes so far. It does not mean humans are 98% chimp. Bananas share 50% of our DNA, but most humans are not 50% banana. As Jeremy Taylor put it: “To call the difference quantitative between alarm calls, food-specific grunts, whoops and Shakespeare; between night nests and twig tools, and the A380 passenger jet; and between retribution and food-sharing, and Aristotle and Mills, is, to my mind, stretching a point, and a bit of an insult to human ingenuity and culture.”

I learned on the trip one does not have to be Bear Grylls to experience adventures. I now have a deeper felt experience of humanity’s evolutionary home. But, still, if your circumstances allow, I would strongly caution you to be wary of the phrase “long-drop toilet” and “bucket shower” when considering accommodations. Just a suggestion.

Several subspecies of chimps and gorillas currently live north of the Congo River, in the forests of Uganda and surrounding regions in Africa. This strongly suggests that the common ancestors of humans, chimps, bonobos, and gorillas lived here. My father, who is big into American history, gets chills when he visits historical sites and stands at the very exact spot of famous events, such as at Gettysburg battlefield or Ford’s Theatre. That is how I felt being in Kibale Forest. Before the human/Pan split, this is where we lived. We are all African.

I do not get as emotional as my father when seeing a sign which reads “George Washington slept here.” But I was deeply moved by the signs all around me in Kibale — in the trees, in the apes, in my heart — that read, to me at least, “My ancestors slept here.”

——————

Photo by Tambako the Jaguar.

Lawrence Rifkin About the Author: Lawrence Rifkin is a physician and a writer. Links to his writings on science, meaning, humanism, and medicine are at lawrencerifkin.wordpress.com. Follow on Twitter @LSRifkin.

The views expressed are those of the author and are not necessarily those of Scientific American.






Comments 1 Comment

Add Comment
  1. 1. RobLL 3:10 pm 07/23/2013

    “… but most humans are not 50% banana(s).” Some of us might put the figure considerably higher. LOL

    Link to this

Add a Comment
You must sign in or register as a ScientificAmerican.com member to submit a comment.

More from Scientific American

Scientific American MIND iPad

Give a Gift & Get a Gift - Free!

Give a 1 year subscription as low as $14.99

Subscribe Now >>

X

Email this Article

X