Profile: Zeresenay Alemseged

What Makes Us Human.

PBS Airdate: October 10, 2012

DAVID POGUE: Zeray Alemseged is a detective, and he's trying to solve an age-old mystery.

ZERESENAY 'ZERAY ' ALEMSEGED (California Academy of Sciences): We are addressing one of the key questions of humanity: "What makes us human? Where do we come from?"

DAVID POGUE: Zeray, himself, comes from Ethiopia, a country known as the "cradle of humanity." It is here, in these dusty hills that Zeray searches for clues to our human origins.

ZERAY ALEMSEGED: I went to start the first Ethiopian-led project in paleoanthropology, ever. Doing that was not easy.

DAVID POGUE: His own origins are only about 400 miles away…

ZERAY ALEMSEGED: I was born in a small town called Axum; happy, running around the obelisks and the big churches.

DAVID POGUE: Here, his father worked in the courts, and his mother ran a small business. Zeray loved learning so much, he snuck into school before he was old enough to attend.

SELAM HAILEMARIAM (Zeray Alemseged's Wife): He'd just go to school without even telling his family. And the desk was so big, because he was so little, he couldn't even fit.

DAVID POGUE: But it wouldn't be easy for a boy from a remote part of Ethiopia to go on to become a full-fledged scientist.

ZERAY ALEMSEGED: I never knew what a scientist was, what a Ph.D. was. We didn't even have TVs, that's how isolated we were.

DAVID POGUE: By the time Zeray was in high school, he had moved to the capital, Addis Ababa. He wanted to become a doctor, but the communist government assigned him to work at the national museum after college. And here, a fossil named Lucy would change the course of his life.

ZERAY ALEMSEGED: Lucy was, basically, 10 meters away from where I was spending my time. That was what triggered the passion that I have now for my work.

DAVID POGUE: Fascinated by this extraordinary skeleton—3.2. million years old, part ape, part human—Zeray was determined to find more evidence of our earliest ancestors.

But first, he'd have to leave Ethiopia and get his Ph.D., in Paris.

ZERAY ALEMSEGED: I was going to France to do my masters and my Ph.D., but I didn't know how to say, "bonjour." You really feel like a baby, starting everything from scratch.

DAVID POGUE: Zeray was beginning a new life as an international scientist.

Today, he spends most of his time in San Francisco, where he heads the anthropology department at the California Academy of Sciences.

ZERAY ALEMSEGED: Places like San Francisco are phenomenal for people like myself. They are so diverse that you have so many types of faces, but at the same time you know that genetically they are over 99.7 percent the same.

DAVID POGUE: The mysteries of human evolution are always on his mind, even when he's playing with his two young children.

ZERAY ALEMSEGED: Because I am interested in the growth and development of early hominids, I play with my kids, you know, looking at their teeth or measuring their heads, which they like also, because it's kind of fun.

Open your mouth.

DAVID POGUE: Zeray's family life may be in the States, but the heart of his research still lies 9,000 miles away, in the deserts of Ethiopia. He spends two months every year combing the sands, hunting for clues about how and when we became human.

Until recently, most of the people finding fossils in Africa were westerners, but Zeray is part of a new generation of African-born scientists, who are leading their own expeditions in the birthplace of humanity.

During Zeray's first season in the field, he had a hunch of where the fossils would be: an unexplored and inhospitable desert region called Dikika.

ZERAY ALEMSEGED: Dikika is sandwiched by two very important and famous sites, so there must be something in between.

DAVID POGUE: But there was a reason no one had chosen to dig there before: A centuries old tribal war. Zeray was even shot at three times, but instead of packing up and running away, he convinced both sides to let him work there.

ZERAY ALEMSEGED: I had decided that nothing can stop me.

DAVID POGUE: For months and months, the group meticulously combed the land for bones.

ZERAY ALEMSEGED: The first week, everybody's laughing, smiling. And then, as time goes by, you see people becoming more angry, more frustrated and some of them even started to give up.

They said, "Okay, we're not going to continue. If you want, you can go ahead."

DAVID POGUE: It seemed like another futile effort, until one of his remaining colleagues called Zeray to come look at something.

ZERAY ALEMSEGED: He shows me this rock. Basically, it looks like a rock. But then I see the part of the cheekbone, and I simply couldn't believe this. I mean, this cannot be happening to me.

DAVID POGUE: This was the rarest kind of fossil Zeray could have found.

ZERAY ALEMSEGED: And then I started to look at the teeth. It was a child. It was a baby. A skeleton of a child? That's impossible.

DAVID POGUE: It's extremely unusual for a baby's skeleton to remain intact for millions of years. Their bones are weak, making them prime candidates for hungry animals.

ZERAY ALEMSEGED: Skeletons are not normally found. Infants are even rarer. When you put all that together, this discovery becomes simply unprecedented.

DAVID POGUE: What's more, the tiny skeleton had striking similarities to the most famous ancient hominid ever found, Lucy, the fossil that had inspired Zeray so many years before.

Lucy, part ape, part human, had been discovered by American paleoanthropologist Don Johanson and his team.

DONALD JOHANSON (Arizona State University, Institute of Human Origins): It's quite clear that we just don't instantly turn into a human from an ape. That it is a set of evolutionary changes over time.

DAVID POGUE: Zeray's new find, whom he named Selam, turned out to be that same ancient species that lived over 3,000,000 years ago.

In his lab in Ethiopia, Zeray set out to see what clues Selam might reveal about how we became human. But it wouldn't be easy, because most of the baby's skeleton was encased in a sandstone block, and he'd become so protective of the child, there was only one person he trusted to unlock it from the stone, himself.

ZERAY ALEMSEGED: What I was doing is using dental drills to remove the sediments, grain by grain.

DAVID POGUE: Day after day, for six years, Zeray chipped away at the block of sandstone.

ZERAY ALEMSEGED: During that process, I met my wife. I have two kids now.

DAVID POGUE: And thanks to his daughter, Zeray got a taste of his old dream to become a doctor, when he had to deliver her himself in a hospital parking lot.

SELAM HAILEMARIAM: We start walking, and all of the sudden I knew the baby is coming down.

ZERAY ALEMSEGED: I have never been trained to deliver a baby. I was trained to discover a baby, a fossil baby, but delivering my own baby in the parking lot was something that I never anticipated.

SELAM HAILEMARIAM: He was he was my hero on that night.

DAVID POGUE: By the time Zeray had finished cleaning Selam, the fossil's human and ape features had become apparent. The shoulder blades showed him that the baby had ape-like climbing arms. He could tell from the knees and hips, that it walked upright like us.

ZERAY ALEMSEGED: The lower part of the skeleton was very human-like: human-like foot, human-like knee bones.

DAVID POGUE: Zeray wanted to see if he could learn even more about the baby, by looking deeper, so he scanned the fossil with x-ray machines, including one of the world's most powerful devices, in Grenoble, France.

ZERAY ALEMSEGED: I spent 12 days working day and night, 24 hours, sleeping in the lab.

FRED SPOOR (Max Planck Institute of Evolutionary Anthropology): With very special x-rays, the skull becomes translucent and you can see this object inside.

DAVID POGUE: The exceptionally detailed scans revealed a surprise, although Selam was just a baby, Zeray could now see adult teeth already formed in the baby's jaw, and that was all the information he needed to tell its age and gender.

DONALD JOHANSON: Now, here, imagine, 3.3 million years old, how do you know what sex it is? He came up with the answer.

DAVID POGUE: By comparing the growth of Selam's teeth to ape and human teeth, Zeray figured out that the baby was three years old when it died. And by comparing the size of the canine teeth to other canines of Selam's species, he could determine that this baby was a girl.

Zeray thought the scans might also reveal some clues about Selam's childhood. By measuring her skull, he figured out her brain size, and then he compared it to three-year-old human and chimp brains.

ZERAY ALEMSEGED: In chimps, by age three, over 90 percent of the brain is formed. In humans, maybe slightly over 70 percent of the brain is formed.

DAVID POGUE: Selam's brain fell somewhere between the two.

ZERAY ALEMSEGED: Maybe this is a hint of the emergence of childhood, which is characteristic of humans.

DAVID POGUE: For Zeray, it seems like a vital advance in human evolution. Our long childhood, when we learn language, culture and the skills necessary for survival, is a hallmark of our species.

Finally, after years of lonely effort, Zeray was ready to share his discovery with the world.

ZERAY ALEMSEGED: I was in this old, moldy room for six years, just talking to Selam, but then that moment of being quiet disappeared.

DAVID POGUE: In a field rife with debate, Selam was received without controversy. She became the biggest story since Lucy. And Zeray, the boy from rural Ethiopia, has become a star in his home country.

ZERAY ALEMSEGED: I was called by the president of Ethiopia once. He was so proud. He said, "We are changing the image of this country." And he said, "You are helping us."

SELAM HAILEMARIAM: Zeray is very famous. Sometimes I tease him, "Where are the photographers? Where are the red carpets?

DAVID POGUE: But Zeray maintains a healthy balance between his life and work, even if he's thinking about human evolution all the time.

ZERAY ALEMSEGED: My family, in a way, gives me a reference as to who I am as an individual, and my work gives me a reference as to who I am as a Homo sapiens. I think that's a very perfect match, in my view.

What Makes Us Human?

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Zeresenay Alemseged Profile

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Image

(Zeresenay Alemseged)

© WGBH Educational Foundation

Zeresenay Alemseged

California Academy of Sciences

Selam Hailemariam

Zeray's wife

Donald Johanson

Paleoanthropologist

Fred Spoor

Paleontologist