Chimps using tools: Archaeology’s most fascinating discovery of 2007

Chimps using tools: Archaeology’s most fascinating discovery of 2007

In its January/February 2008 issue, Archaeology Magazine listed what it thought were the top 10 discoveries of 2007. Among these was the discovery of tool use by ancient chimpanzees.

A team of researchers led by Dr. Julio Mercader of the University of Calgary in Alberta undertook excavations in the West African nation, Côte d’Ivoire. They encountered a series of hammer stones, some of them dating back 4,300 years, that are thought to have been used by chimps to crack open nuts. Starch residue from several nuts known to be staples in the chimpanzee diet, but not the human diet, suggests that chimps, rather than humans, manufactured these tools.

Dr. Mercader was the first to coin the term “chimpanzee archaeology.”  His discoveries have resulted in the opening of a new research niche within archeology bearing the same name.

In various ways, this particular development is of great importance in the field of human origins. As mentioned in an earlier blog, the capacity of making complex tools is considered uniquely human.

Discoveries like these have prompted humans to add the qualifier “complex” in front of the word “tool.” It is an elegant, yet necessary, way to acknowledge that non-human beings (in this case, chimps are also capable of manufacturing tools, but that until further notice, it is only us humans who use, say, e-mail.

The announcement also showcases how science works: its practitioners are by nature curious creatures. Someone somewhere will inevitably come up with new questions that they will investigate to yield further insights into human behavior. In this case, such insight was achieved by researching non-human primate tool making. For this step forward, we owe Dr. Mercader and his colleagues a debt of gratitude.

A Letter From Lucy: Making no bones about it. (Pun intended)

The other day, I got a visit from Mike. He seemed to be quite an upstanding guy. My kind, really. I had always wondered what would happen to my family. Would they thrive? Would they all be eaten by wild animals before they got a chance to leave Africa? So many questions and no answers. After 3 million years, the wondering can drive you nuts!

And then, I got the chance to travel to North America. Again. This time to see people. I’ve met thousands since arriving, and been amazed at how many different kinds there are – and how happy most seem to see me. Then, there was Mike.

I saw him early in January this year. I’ve been here a while now, so I’ve got the first-impressions thing down. As we exchanged greetings, I passed along my best wishes and a Happy New Millennium from all the folks back home in Ethiopia.

Mike seemed perturbed though. He thanked me for the wishes, but then his eyes kind of glazed over. He seemed not just to see through me, but rather past me. Instead of learning about me, he seemed lost in his own thoughts. As if he did not get who I was and what I represented. I wanted to shout “Mike! It’s me! Lucy. You know, one of your distant ancestors.”

My cries were left unanswered. Mike slowly turned and walked away. “Oh, well,” I thought, “at least he seems to be doing well.” Still bipedal and obviously a much bigger brain. I’m so proud! Uses fancy tools too, it looked like. I never got a chance to use them, and I’m still trying to figure out what most of them are for. We had to survive using our small brains, see. No stone-tipped spears, no burning torches to keep the animals at bay. Definitely no cell phones. Instead we climbed trees at night to stay out of trouble and during the day, as we stood upright – “Just like you, Mike,” I kept thinking – we kept an eye out for predators. Not easy being me, you know. But we all managed somehow.

In fact, I was happy to learn that my kind was around for 600,000 years. Mike, I understand that your people have been around for about 200,000 years. Cool. Keep up the good work. Another 400,000 years and you’ll have been just as successful as we were.

But you left me with a lingering concern for your doubts. I kept thinking “Here I am, Mike. Real bones. Real fossilized remains.” You seemed unimpressed. “Not a replica, and certainly not a fake either,” I wanted to add, but to no avail. You were gone.

Mike, I’ll make no bones about it: thank you for your visit. I was very glad to meet you. But you should use that large brain you’ve got; it’s telling you to look deeper. There is more to me than what you saw.

I am Lucy, and you are my legacy.

PS: Not to hurt your feelings, but I have had dates before, Mike. One guy really fancied me. I think I like him, too.


Discovering behavior: a step-by-step process

 As discussed in my last entry, the process of tool making has left us lots of clues to the behavior of some of our ancestors. Some of the best information – as it gives us a window into how a species thinks – is the manufacturing process itself.

By continuously experimenting and by observing those few contemporary populations where stone tools are still made, experimental archaeologists gain insights in how ancient stone tools very likely were made as well. Things can get technical very quickly, yet also exciting.

When stone tools are made and lots of steps are required, a lot of waste material is produced. This waste, known by the French term of debitage, often collects at the feet of the tool maker, where it was left.

Using these fragments as pieces of a very old three-dimensional puzzle, stone tool experts have been able to reconstruct the stages in which an actual stone tool was once made. This is not an estimate, but rather the step-by-step reconstruction of the sequence in which each flake was chipped off the original stone.

In some extraordinary cases, researchers can look at stone tools and determine not only the manufacturing process of that particular tool, but also establish whether the person who made it was left-handed.  The angles under which the debitage was removed from the core produced this extraordinary insight. 

In this regard, the work of these stone tool specialists not only requires a lot of patience, but it also approximates approach taken by detectives. With patience, careful observation, reasoning, and in some cases, advanced technology, you can see how it is possible, and very rewarding, to reconstruct ancient hominid behavior.