It was just another morning in Africa. The paleoanthropologist Donald C. Johanson was sipping his morning coffee with his young colleague Tom Gray, trying to decide where to go fossil hunting for the day. He was drawn to the remote parts of Ethiopia by his desire to find the skeletal remains of our distant ancestors or at least their close relatives. He studied the evolution of man and other hominids and was now searching for fossils from the period when our ancestors had just started to stand on two feet. His young friend Tom, who was at the time a postdoctoral researcher, had a different mission. With the aid of fossil remains of plants and animals he was to reconstruct as accurately as possible the natural environment which prevailed several million years ago when our ancestors roamed these lands. It is known that Africa used to be much more forested, even in areas where today only desert remains. The characteristics of an environment which existed in a certain area in a certain period could most easily be reconstructed from fossil finds.
Fossil hunting
That day, Donald did not intend to leave the base camp where scientists were lodged as he had to catch up on a lot of unfinished administrative work. Only a day before, Richard and Mary Leakey, two famous and successful human fossil hunters who lived in nearby Kenya, had concluded their visit of the camp. During their stay Donald did not spend much time on cataloguing the discovered specimens, so he decided to make up for the lost work. But, as he later remembered, something drove him to the field that day, even though he was aware that it would be wiser to stay in the tent and arrange his papers. Even so, he wrote in his journal: “November 24th 1974. I’m spending this morning on location 162 with Gray. Feeling good.”
Looking for fossils is time-consuming work requiring a fair amount of luck. Many renowned paleoanthropologists spent their entire lives wandering through potential sites without succeeding in finding a single relevant specimen. This was Donald’s third expedition to the Ethiopian region Hadar and he had already gotten quite lucky with some of his finds, but he certainly never expected that it would be that very day that he would come upon the trail leading him to the fossils that remain one of the most important paleoanthropological discoveries to this day.
After they have had their coffee, Donald and Gray got into one of the four Land Rovers and drove to site No. 162. Their destination was actually only a few kilometers away from the scientific expedition’s base camp, but they needed half an hour to reach it because of the difficult terrain. When they arrived, the African sun was already scorching hot and all the morning freshness had gone from the air.
The Hadar region in Ethiopia is well known for having fossils scattered all across the surface of its ground. Hadar is the center of the Afar Desert where there once was a lake in which all different kinds of sediments accumulated. When the lake dried out they surfaced, bearing witness to the events that took place in this area several million years ago.
When searching for fossils, the most important thing to have is an eye for distinguishing a potential fossil from a common rock. Then, only a careful and systematic analysis of the area remains to be performed until someone gets lucky. While searching through site No. 162 that morning, all that Tom and Donald found were a couple of teeth belonging to an extinct species of horse, a part of an extinct pig’s skull, and a piece of a monkey’s jaw. Noon was approaching and the temperatures had risen to more than 40 degrees Celsius.
A three-million-year-old skeleton
After an entire morning of searching for fossils, Tom and Donald decided to head back to their vehicle and drive off for lunch. When they were already on their way back, Donald decided to scan the area again, even though others had already examined it at least twice without finding anything. His eyes stopped on a small bone penetrating the surface of the ground. Donald suddenly cried: “It’s a part of a hominid’s arm!” But Tom did not believe him: “It can’t be. It’s too small. It probably belongs to a monkey.”
However, when they came across a piece of a skull lying nearby even Tom was completely convinced that it was not a monkey, but a hominid. After a more thorough examination of the surroundings, they also discovered some vertebrae and a part of a pelvis. They immediately realized that this was almost certainly one of the greatest discoveries in the history of paleoanthropology. Never before had a scientist succeeded in finding so many preserved parts belonging to an individual hominid of this age. When they found the remains of ribs, they started to jump for joy, in spite of the temperature which was now well over forty degrees.
They carefully marked the site, gathered some more remains of the jaw and set off for the camp to get some help. On the way back they picked up two geologist colleagues who were carrying samples of rocks. Tom was so excited that he started to sound the horn before they even reached the camp and started shouting that they had discovered something truly important.
Soon, all of the members of the expedition were on site 162 by the remains of the skeleton that had been discovered by Donald and Tom only a couple of hours earlier. During the three weeks that followed they diligently dug through every part of the area looking for as many remains they could include in the reconstruction of the skeleton as possible. In the end, they gathered several hundred pieces of bones which represented approximately forty percent of the skeleton belonging to a single individual.
But who was this being they had excavated? At first, the only thing they could be certain about was that nobody had ever discovered anything like it. The first night after the discovery had been made nobody went to bed, because the excitement was too overwhelming. They discussed the find into the late hours of the night, drinking beer and going over all the possible implications of this important discovery. A portable radio was loudly playing a tape on which the song Lucy in the Sky with Diamonds was repeated several times. Sometime during the night the fossil happened to get stuck with the name Lucy and we have known it as Lucy ever since, even though the finds official name is AL 288-1.
Such a small brain, and already walking upright
Lucy was only a meter high and weighed a bit less than thirty kilos. She was classified as a new species of hominids for which the technical term on the site was Australopithecus Afarensis. When the world found out about this important discovery made by the researchers in Ethiopia, Lucy became a true sensation. From the form of her pelvis the scientists concluded and affirmed that she had walked on two feet. With 3.2 million years of age she was the oldest preserved specimen of a man’s ancestor who already walked upright.
Only four years later in a place called Leatoli in the nearby Tanzania, another group of scientists led by Mark Leakey came across a series of footprints that had been preserved in volcanic ash which, mixed with rain, had solidified into a substance similar to cement. When a nearby volcano erupted 3.7 million years ago, there was, among other creatures, a being like Lucy walking on two feet across the wet ashes.
Before Lucy was discovered, scientists were convinced that our ancestors decided to walk on two feet because they had gradually become more intelligent and realized that freeing up the hands might be a good idea. With their hands they could do useful things while walking, unlike monkeys. Lucy refuted this theory as she obviously walked on two feet, yet her head was not much bigger than that of a chimpanzee. All evidence implies that our ancestors had begun to walk upright long before they developed a brain big enough to allow them to figure out that it might be a good idea.
The latest research comparing the consumption of energy used for walking in chimpanzees and humans shows that humans with their upright walk use four times less energy than chimpanzees. This means that it was definitely an important development which, among other things, enabled the brain to start consuming more energy. As we all know, people use great amounts of energy even when we sit still and do nothing but think. About one fifth of all energy produced in our bodies is spent to fuel the brain, which is a lot in comparison to what other animal species use.
To supply our brain with energy, people need appropriate food, preferably cooked so we can digest it more easily and absorb more nutritious substances than we would if we consumed it raw. To obtain meat and other food, rich in calories, we need tools, weapons and knowledge for which free hands and a brain of an appropriate size are essential.
The African Lucy is now on a six-year tour of the U.S. As a part of the promotion, scientists in cooperation with the Ethiopian authorities decided to include the fossil remains of our distant ancestor in the exposition Lucy’s Legacy: The Hidden Treasures of Ethiopia which began its worldwide tour in Texas (Houston Museum of Natural Science) and is currently on display in Seattle (Pacific Science Center).
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