"IMAGINE"

The Human Being, or Being Human...

A New Kind of Ancestor

H. naledi was much closer in appearence to Homo species such as H. erectus than to australopithecines, such as Lucy. But it possesses enough traits shared with no other member of our genus that it warrants a new species name.

"Lucy"

Australopithecus afarensis

3.2 million years ago

Adult Female

3 ft 8 in

60-65 lbs

"Turkana Boy"

Homo erectus

1.6 million years ago

Adolescent Male

5 ft

110-115 lbs

"Rising Star Hominin"

Homo naledi

Date Unknown

Adult Male

4 ft 10 in

100-110 lbs

From left to right:

1. "Lucy" (Australopithecus afarensis)

3.2 million years ago

Adult Female

3 ft 8 in; 60-65 lbs

2. "Turkana Boy" (Homo erectus)

1.6 million years ago

Adolescent Male

5 ft; 110-115 lbs

3. "Rising Star Hominin" (Homo naledi)

Date Unknown

Adult Male

4 ft 10 in; 100-110 lbs

Art: John Gurche
Sources: Lee Berger, University of the Witwatersrand (WITS), South Africa; John Hawks, University of Wisconsin-Madison

“It’s an animal that appears to have had the cognitive ability to recognize its separation from nature,” he said.

How Old Is It?

The mysteries of what H. naledi is, and how its bones got into the cave, are inextricably knotted with the question of how old those bones are—and for the moment no one knows. In East Africa, fossils can be accurately dated when they are found above or below layers of volcanic ash, whose age can be measured from the clocklike decay of radioactive elements in the ash. At Malapa, Berger had gotten lucky: The A. sediba bones lay between two flowstones—thin layers of calcite deposited by running water—that could also be dated radiometrically. But the bones in the Rising Star chamber were just lying on the cave floor or buried in shallow, mixed sediments. When they got into the cave is an even more intractable problem to solve than how.

Most of the workshop scientists fretted over how their analysis would be received without a date attached. (As it turned out, the lack of a date would prove to be one impediment to a quick publication of the scientific papers describing the finds.) But Berger wasn’t bothered one bit. If H. naledi eventually proved to be as old as its morphology suggested, then he had quite possibly found the root of the Homo family tree. But if the new species turned out to be much younger, the repercussions could be equally profound. It could mean that while our own species was evolving, a separate, small-brained, more primitive-looking Homo was loose on the landscape, as recently as anyone dared to contemplate. A hundred thousand years ago? Fifty thousand? Ten thousand? As the exhilarating workshop came to an end with that fundamental question still unresolved, Berger was sanguine as always. “No matter what the age, it will have tremendous impact,” he said, shrugging.

Berger’s Triumph

A few weeks later, in August of last year, he traveled to East Africa. To mark the occasion of Louis Leakey's description of H. habilis, Richard Leakey had summoned the leading thinkers on early human evolution to a symposium at the Turkana Basin Institute, the research center he (along with the State University of New York at Stony Brook) had established near the western shore of Lake Turkana in Kenya.

The purpose of the meeting was to try to come to some consensus over the confounding record of early Homo, without grandstanding or rancor—two vices endemic to paleoanthropology. Some of Lee Berger’s harshest critics would be there, including some who’d written scathing reviews of his interpretation of the A. sediba fossils. To them, he was an outsider at best, a hype artist at worst. Some threatened not to attend if he were there. But given the Rising Star discovery, Leakey could hardly

The Braided Stream

When a major new find is made in human evolution—or even a minor new find—it’s common to claim it overturns all previous notions of our ancestry. Perhaps having learned from past mistakes, Berger doesn’t make such assertions for Homo naledi—at least not yet, with its place in time uncertain. He doesn’t claim he has found the earliest Homo, or that his fossils return the title of “Cradle of Humankind” from East to South Africa. The fossils do suggest, however, that both regions, and everywhere in between, may harbor clues to a story that is more complicated than the metaphor “human family tree” would suggest.

“What naledi says to me is that you may think the record is complete enough to make up stories, and it’s not,” said Stony Brook’s Fred Grine. Maybe early species of Homo emerged in South Africa and then moved up to East Africa. “Or maybe it’s the other way around.”

Berger himself thinks the right metaphor for human evolution, instead of a tree branching from a single root, is a braided stream: a river that divides into channels, only to merge again downstream. Similarly, the various hominin types that inhabited the landscapes of Africa must at some point have diverged from a common ancestor. But then farther down the river of time they may have coalesced again, so that we, at the river’s mouth, carry in us today a bit of East Africa, a bit of South Africa, and a whole lot of history we have no notion of whatsoever. Because one thing is for sure: If we learned about a completely new form of hominin only because a couple of cavers were skinny enough to fit through a crack in a well-explored South African cave, we really don’t have a clue what else might be out there. 

More About the Naledi Fossils

Naledi Fossils

Where Is the Birthplace of Humankind? South Africa and East Africa Both Lay...

brand-new specimens found on the east side of the lake, including a nearly complete foot. When it was his turn to speak, Bill Kimbel of the Institute of Human Origins described a new Homo jaw from Ethiopia dated to 2.8 million years ago—the oldest member of our genus yet. Archaeologist Sonia Harmand of Stony Brook University dropped an even bigger bombshell—the discovery of dozens of crude stone tools near Lake Turkana dating to 3.3 million years ago. If stone tools originated half a million years before the first appearance of our genus, it would be hard to argue anymore that the defining characteristic of Homo was its technological ingenuity.

Berger meanwhile was uncommonly subdued, adding little to the discussion, until the topic turned to a comparison of A. sediba and H. habilis. It was time.

“More of interest perhaps to this debate is Rising Star,” he offered. For the next 20 minutes he laid out all that had happened—the serendipitous discovery of the cave, the crash analysis in June, and the gist of its findings. While he talked, a couple of casts of Rising Star skulls were passed hand to hand.

Then came the questions. Have you done a cranio-dental analysis? Yes. The H. naledi skull and teeth place it in a group with Homo erectus, Neanderthals, and modern humans. Closer to H. erectus than H. habilis is? Yes. Are there any tooth marks on the bones from carnivores? No, these are the healthiest dead individuals you’ll ever see. Have you made progress on the dating? Not yet. We’ll get a date sometime. Don’t worry.

Then, when the questions were over, the gathered doyens did something no one expected, least of all Berger. They applauded.

about a completely new form of hominin only because a couple of cavers were skinny enough to fit through a crack in a well-explored South African cave, we really don’t have a clue what else might be out there. 

of Wisconsin-Madison

“It’s an animal that appears to have had the cognitive ability to recognize its separation from nature,” he said.

Naledi Fossils

Where Is the Birthplace of Humankind? South Africa and East Africa Both Lay...

The new human fossils from South Africa have added fuel to a long-standing debate over the geographical origins

A New Kind of Ancestor

H. naledi was much closer in appearence to Homo species such as H. erectus than to australopithecines, such as Lucy. But it possesses enough traits shared with no other member of our genus that it warrants a new species name.

"Lucy"

Australopithecus afarensis

3.2 million years ago

Adult Female

3 ft 8 in

60-65 lbs

"Turkana Boy"

Homo erectus

1.6 million years ago

Adolescent Male

5 ft

110-115 lbs

"Rising Star Hominin"

Homo naledi

Date Unknown

Adult Male

4 ft 10 in

100-110 lbs

From left to right:

1. "Lucy" (Australopithecus afarensis)

3.2 million years ago

Adult Female

3 ft 8 in; 60-65 lbs

2. "Turkana Boy" (Homo erectus)

1.6 million years ago

Adolescent Male

5 ft; 110-115 lbs

3. "Rising Star Hominin" (Homo naledi)

Date Unknown

Adult Male

4 ft 10 in; 100-110 lbs

Art: John Gurche
Sources: Lee Berger, University of the Witwatersrand (WITS), South Africa; John Hawks, University of Wisconsin-Madison

“It’s an animal that appears to have had the cognitive ability to recognize its separation from nature,” he said.

How Old Is It?

The mysteries of what H. naledi is, and how its bones got into the cave, are inextricably knotted with the question of how old those bones are—and for the moment no one knows. In East Africa, fossils can be accurately dated when they are found above or below layers of volcanic ash, whose age can be measured from the clocklike decay of radioactive elements in the ash. At Malapa, Berger had gotten lucky: The A. sediba bones lay between two flowstones—thin layers of calcite deposited by running water—that could also be dated radiometrically. But the bones in the Rising Star chamber were just lying on the cave floor or buried in shallow, mixed sediments. When they got into the cave is an even more intractable problem to solve than how.

Most of the workshop scientists fretted over how their analysis would be received without a date attached. (As it turned out, the lack of a date would prove to be one impediment to a quick publication of the scientific papers describing the finds.) But Berger wasn’t bothered one bit. If H. naledi eventually proved to be as old as its morphology suggested, then he had quite possibly found the root of the Homo family tree. But if the new species turned out to be much younger, the repercussions could be equally profound. It could mean that while our own species was evolving, a separate, small-brained, more primitive-looking Homo was loose on the landscape, as recently as anyone dared to contemplate. A hundred thousand years ago? Fifty thousand? Ten thousand? As the exhilarating workshop came to an end with that fundamental question still unresolved, Berger was sanguine as always. “No matter what the age, it will have tremendous impact,” he said, shrugging.

1. How Killing Elephants Finances Terror in Africa

The purpose of the meeting was to try to come to some consensus over the confounding record of early Homo, without grandstanding or rancor—two vices endemic to paleoanthropology. Some of Lee Berger’s harshest critics would be there, including some who’d written scathing reviews of his interpretation of the A. sediba fossils. To them, he was an outsider at best, a hype artist at worst. Some threatened not to attend if he were there. But given the Rising Star discovery, Leakey could hardly not invite him.

“There’s no one on Earth finding fossils like Lee is now,” Leakey said.

For four days the scientists huddled together in a spacious lab room, its casement windows open to the breezes, casts of all the important evidence for early Homo spread out on tables. One morning Meave Leakey (who’s also a National Geographic explorer-in-residence) opened a vault to reveal brand-new specimens found on the east side of the lake, including a nearly complete foot. When it was his turn to speak, Bill Kimbel of the Institute of Human Origins described a new Homo jaw from Ethiopia dated to 2.8 million years ago—the oldest member of our genus yet. Archaeologist Sonia Harmand of Stony Brook University dropped an even bigger bombshell—the discovery of dozens of crude stone tools near Lake Turkana dating to 3.3 million years ago. If stone tools originated half a million years before the first appearance of our genus, it would be hard to argue anymore that the defining characteristic of Homo was its technological ingenuity.

Berger meanwhile was uncommonly subdued, adding little to the discussion, until the topic turned to a comparison of A. sediba and H. habilis. It was time.

“More of interest perhaps to this debate is Rising Star,” he offered. For the next 20 minutes he laid out all that had happened—the serendipitous discovery of the cave, the crash analysis in June, and the gist of its findings. While he talked, a couple of casts of Rising Star skulls were passed hand to hand.

Then came the questions. Have you done a cranio-dental analysis? Yes. The H. naledi skull and teeth place it in a group with Homo erectus, Neanderthals, and modern humans. Closer to H. erectus than H. habilis is? Yes. Are there any tooth marks on the bones from carnivores? No, these are the healthiest dead individuals you’ll ever see. Have you made progress on the dating? Not yet. We’ll get a date sometime. Don’t worry.

Then, when the questions were over, the gathered doyens did something no one expected, least of all Berger. They applauded.

Naledi Fossils

Where Is the Birthplace of Humankind? South Africa and East Africa Both Lay...

The new human fossils from South Africa have added fuel to a long-standing debate over the geographical origins