Last Ape Standing: The Seven-Million-Year Story of How and Why We Survived (17 page)

The odd thing about that was that their tools instead resembled Neanderthal implements, yet they themselves were not Neanderthal. The best guess is that somehow they, or earlier generations, had crossed paths with their northern cousins and borrowed some of their technology because it was better than their own.

For all we know, these were early
Homo sapiens
explorers, the Marco Polos and Vasco da Gamas of their day, wandering the Arabian Peninsula while less adventurous
Homo sapiens
tribes remained on the home continent. By all accounts, their expedition wasn’t terribly successful.
The skeletons of red and fallow deer, small animals, aurochs, and some seafood shells show they gave colonizing the area a game effort, but their excursions never made it beyond the hills of Qafzeh and barely beyond the borderlands of Africa. There is no evidence that any of their kind ever made it north of this sector of the Middle East, not this far back in human prehistory. Maybe the explorers retreated home across the Red Sea straits, played out and tired; or maybe those eleven buried were put to rest by a last few survivors, or maybe they hung on for years in a small group like a prehistoric version of the settlers at Plymouth Rock or Jamestown, until disaster or disease at last carried them off. No one knows.

In the same area, paleoanthropologists recently discovered that Neanderthal explorers likewise found their way south into Galilee thirty thousand years later (December 26 or so in the HEC), but they came from the north rather than the south. Did the fair–haired, bulky colonists run into lithe, dark–skinned people from across the Arabian straits? If so, did the Neanderthals do them in or run them off the peninsula back to Africa?

“At that point,” says paleoanthropologist Nicholas J. Conard of the University of Tübingen in Germany, “the two species are on pretty equal footing.” The tools of both
Homo sapiens
and Neanderthals would have been about equally advanced, and given what the Neanderthals had been facing in the wilds and weather of Europe the past 130,000 years, they would have been an extremely tough breed. Modern humans may not have been their match, not yet. Or perhaps they mated and their offspring dissolved into the continent and disappeared from the map. Either way, it seems that for another twenty thousand years or so
Homo sapiens
ceded Asia to their barrel–chested cousins.

Whatever happened, we do know that Neanderthals and
Homo sapiens
eventually encountered one another in Europe sometime after our long–lost ancestors finally made their big push out of the Dark Continent. But what about the East and the
erectus
bands that had begun heading off toward India and China and Southeast Asia two million years earlier? What became of them and their ancestors, and did ours make contact with them?

Scientists haven’t uncovered direct fossil evidence of even a single meeting—no burial sites, artifacts, or bones—but in 2004 a team that included biologist Dale Clayton and anthropologist Alan Rogers, both working at the University of Utah, proved that our ancestors did
indisputably have a close encounter with another human species in the Far East sometime around twenty-five thousand years ago. How could they know if there was no fossil evidence?

Head lice.

Like every other living thing on Earth, head lice have DNA. And like humans or finches or predatory big cats, different species of lice have different DNA. Anytime we find head lice on ourselves—breakouts among schoolchildren are more common than parents would prefer—we find two kinds that are rarely separated. Despite nearly always being in one another’s company, however, each initially evolved separately while dining on two different species of early humans. One of those species led to us. The other is extinct. For those two species of lice to coexist today, both had to have come into close contact sometime in the past.

By studying their DNA and then time–stamping the evolution of both strains, the Utah study concluded that at least one meeting took place sometime between thirty thousand and twenty-five thousand years ago in Asia. “We’ve discovered the ‘smoking louse,’” Clayton wryly observed. “The record of our past is written in our parasites,” added Rogers.

What makes this discovery especially surprising, aside from its creative use of parasites to track human behavior, is that most paleoanthropologists believe that
Homo erectus
met his end seventy thousand years ago, long before this encounter could possibly have taken place. Nevertheless it’s difficult to dispute the evidence. Parasites reflect the evolution of their hosts. They rely on them for their livelihood after all, and their fortunes and survival are inextricably bound. So some direct descendant of
Homo erectus
must have survived forty–five thousand years longer than previously believed. Whoever this species was, the genetic history of the head lice that colonized it shows that it split into two species around 1.18 million years ago, about the same time that
Homo erectus
and our direct ancestors in Africa, possibly
Homo ergaster
, parted ways. That explains why the lice themselves also parted company and eventually evolved into two species in the first place.

The lice reveal something else fascinating (who knew the little buggers could be so informative?). The
Homo sapiens
strain corroborates evidence that our direct ancestors had been reduced to extremely small numbers between one hundred thousand and fifty thousand
years ago before rebounding and rapidly expanding, with their head lice, to colonize the rest of the world. This supports mitochondrial genetic evidence that our kind nearly met an early and tragic (at least for us) end around seventy thousand years ago before recovering to spend the next fifty thousand years becoming the planets dominant species on Earth.

Strangely enough, the archaic lice, the ones that made their homes on the heads of the species no longer with us, show not an iota of evidence that they went through either a similar bottleneck or population explosion. During those years, when
Homo sapiens
had nearly been rubbed out, perhaps by the Olympian–scale eruption at Lake Toba in Indonesia, these other humans were apparently getting along just fine. One theory is that they were safely upwind of the explosion and didn’t feel the immediate, violent effects, though this doesn’t explain how they managed to survive the subsequent global volcanic winter some scientists feel resulted from the gargantuan blast. All indications are that this line of humanity did just fine, at least until they crossed paths again with the
Homo sapiens
descendants of the species that they had split off from more than a million years earlier.

It is not as crazy as it might once have been thought that a more modern descendant of
Homo erectus
was still alive as recently as twenty-five thousand years ago. The more scientists examine the past, the more surprises they find. They found a particularly big one when the remnants of an entirely new human species that no one had had the slightest inkling had ever existed came to light in 2004 at Liang Bua, a cave on the island of Flores, 388 miles east of Java in Indonesia. After much debate and head scratching, most paleoanthropologists agreed that
Homo floresiensis
, as these remarkable creatures came to be known, was a bright, toolmaking human. The big surprise, beyond the discovery that these people existed at all, was their startlingly Lilliputan stature. The press and even astounded scientists took to calling them “hobbits.” One three–foot–three–inch–tall adult–woman skeleton that was discovered turned out to be even shorter than Lucy.

Their brain size at 420 cc was also not much larger than Lucy’s, a hominin that had walked the earth more than 3 million years earlier. Yet these creatures could control fire, make sophisticated tools, and hunt game, though it’s still an open question as to whether they could speak or used any advanced language. How, scientists have wondered,
could a species with a brain less than one third the size of ours pull off these sorts of impressive feats?

Our best evidence indicates that the Flores hobbits lived between ninety–five thousand and seventeen thousand years ago, the descendants of earlier
Homo erectus
settlers who were eventually reduced in size by an odd evolutionary phenomenon scientists call island dwarfing. Island dwarfing happens when natural forces cause species to shrink in size over time in isolated locations, presumably because resources are severely limited. The theory is that in a kind of ecological bargain, animals grow smaller rather than starve. By reducing their size, both resources and diversity are both preserved, and life goes on with predator, prey, and the entire ecological niche surviving in a sort of pygmy state. Dwarfing can have other advantages under these circumstances. It’s easier to stay warm or cool when you are smaller, which saves energy and requires less food. On Flores, in addition to the hobbits themselves, scientists have found examples of a small, elephant–like creature called
Stegodon
, an animal the hobbits apparently hunted with some enthusiasm.

Because of
Homo floresiensis
’ size, especially the size of its brain, scientists have enjoyed some spirited debate about whether it came to the island in the form of a lean and tall
Homo erectus
(remains of
erectus
have been found on nearby Java), then shrank over time due to island dwarfing, or whether it may have been the descendant of smaller, Lucy–size creatures who came out of Africa before
erectus
and then made their way somehow to the islands of Indonesia.

Could a smaller, less intelligent species such as
Homo habilis
or
Australopithecus afarensis
have made the ten–thousand–mile journey by land to Flores without the benefit of fairly advanced tools? It would be a remarkable feat. Their brains were considerably smaller and considerably less sophisticated than all varieties of
Homo erectus
. It seems a stretch that such wanderers would have evolved to develop the sort of technology scientists found on the island without the benefit of their brains’ growing larger and more complex beforehand. It’s more likely that somehow their brains had advanced to the sophisticated wiring of
Homo erectus
, at least, and then grown mysteriously smaller while not giving up the advantages of that wiring. In other words the brain grew tinier, but its complex architecture remained intact, like the perfectly replicated miniatures of homes and furniture you might see in a history museum.

The current consensus is that the last hobbit departed about seventeen thousand years ago, but some have speculated they may have lived on. Anthropologist Gregory Forth has hypothesized that Flores hobbits might be the source of stories among local tribes about the Ebu Gogo, small, hairy cave dwellers who supposedly spoke a strange language and were reportedly seen by Portuguese explorers who came to the islands in the early 1600s. Henry Gee, a senior editor at
Nature
magazine, has even opined that species like
Homo floresiensis
might still exist in the unexplored tropical forests of Indonesia.
⁷

It makes you wonder how many other human species we may find as we comb through the planet. Could small pockets of
erectus
descendants have managed to survive in remote areas throughout Asia, or even made their way to North America? Could there be something to the sightings of yeti in the Himalayas or Big Foot in the American West after all?

The point is that almost anything is proving to be possible when it comes to human evolution, even hobbits, and if they nearly survived until the first great agricultural civilizations began to gain a toehold, then could the descendants of
Homo erectus
, whatever we might call them, have remained abroad for our ancestors to meet as they trekked through Asia on their way to Indonesia and Australia?

Possibly a larger, more evolved version of
Homo floresiensis
had survived Toba and the ice ages that battered the Neanderthals in Europe and reduced
Homo sapiens
to a few clans hanging on by a wispy thread in a drought–ridden Africa. It would have been no mean feat to survive that ice age, but maybe in Southeast Asia, on the ancient continent of Sundaland, life was less deadly than in other parts of the world. It could even be that the species from which we acquired the second brand of head lice we carry around with us today are a gift from the hobbits themselves, Denisovans, or the newly discovered Red Deer Cave people of China.
⁸

For now we can only speculate, but that we met these people—whoever they were—and that they so generously shared their parasites with us indicates that our encounter was of the close kind. Tight quarters are generally required when divvying up lice. Unfortunately, there is no way to decipher exactly what variety the close encounters were. Possibly we killed the people and took their clothing, and the bugs came in the bargain. Murder on a large scale
has
, unfortunately, been
known to take place when a new, powerful group of humans finds less technologically advanced people. We don’t have to look any further than the wrecked civilizations of the Incas and Mayans in South America, Aborigines in Australia, and Native Americans in the United States for proof. It is also possible we simply colonized the same space and outcompeted them for limited resources with better hunting strategies, better tools and weapons, and more elaborate cooperation. Or maybe we mated with them, either forcibly or affectionately, or both. We may even have run across them when they had reached the end of their evolutionary rope, and their parting gifts to humanity were a bloodthirsty bug and a few hunting grounds.

Probably, whoever they were, they were not as cerebrally gifted as the
Homo sapiens
they crossed paths with. But that doesn’t mean they weren’t bright. They were certainly far more intelligent than today’s chimpanzee or gorilla, which are devilishly clever in their own right. If they were directly descended from
Homo erectus
, they may have lacked advanced language.
Homo erectus
is unlikely to have mastered the spoken word, though he may have used complex gestures or other vocalizations to communicate. Speech and language are not always the same thing, as the thousands who speak American Sign Language can attest.