November 2003 issue/ Scientific American
 
Stunning finds in the Republic of Georgia upend long-standing ideas 
about the first hominids to journey out of Africa. 

By Kate Wong  

 With a brain half the size of a modern one and a brow reminiscent of 
Homo habilis, this hominid is one of the most primitive members of our 
genus on record. Paleoartist John Gurche reconstructed this 1.75-
million-year-old explorer from a nearly complete teenage H. erectus 
skull and associated mandible found in Dmanisi in the Republic of 
Georgia. The background figures derive from two partial crania recovered 
at the site. 
Overview / The First Colonizers 

We shall not cease from exploration
And the end of all our exploring 
Will be to arrive where we started 
And know the place for the first time. 
--T. S. Eliot,  Four Quartets: "Little Gidding" 

In an age of spacecraft and deep-sea submersibles, we take it for 
granted that humans are intrepid explorers. Yet from an evolutionary 
perspective, the propensity to colonize is one of the distinguishing 
characteristics of our kind: no other primate has ever ranged so far and 
wide. Humans have not always been such cosmopolitan creatures, however. 
For most of the seven million years or so over which hominids have been 
evolving, they remained within the confines of their birthplace, Africa. 
But at some point, our ancestors began pushing out of the motherland, 
marking the start of a new chapter in our family history. 

It was, until recently, a chapter the fossil record had kept rather 
hidden from view. Based on the available evidence--a handful of human 
fossils from sites in China and Java--most paleoanthropologists 
concluded that the first intercontinental traveling was undertaken by an 
early member of our genus known as Homo erectus starting little more 
than a million years ago. Long of limb and large of brain, H. erectus 
had just the sort of stride and smarts befitting a trailblazer. Earlier 
hominids, H. habilis and the australopithecines among them, were mostly 
small-bodied, small-brained creatures, not much bigger than a modern 
chimpanzee. The H. erectus build, in contrast, presaged modern human 
body proportions. 
Curiously, though, the first representatives of H. erectus in Africa, a 
group sometimes referred to as H. ergaster, had emerged as early as 1.9 
million years ago. Why the lengthy departure delay? In explanation, 
researchers proposed that it was not until the advent of hand axes and 
other symmetrically shaped, standardized stone tools (a sophisticated 
technological culture known as the Acheulean) that H. erectus could 
penetrate the northern latitudes. Exactly what, if anything, these 
implements could accomplish that the simple Oldowan flakes, choppers and 
scrapers that preceded them could not is unknown, although perhaps they 
conferred a better means of butchering. In any event, the oldest 
accepted traces of humans outside Africa were Acheulean stone tools from 
a site called 'Ubeidiya in Israel. 

Brawny, brainy, armed with cutting-edge technology--this was the hominid 
hero Hollywood would have cast in the role, a picture-perfect pioneer. 
Too perfect, it turns out. Over the past few years, researchers working 
at a site called Dmanisi in the Republic of Georgia have unearthed a 
trove of spectacularly well preserved human fossils, stone tools and 
animal remains dated to around 1.75 million years ago--nearly half a 
million years older than the 'Ubeidiya remains. It is by 
paleoanthropological standards an embarrassment of riches. No other 
early Homo site in the world has yielded such a bounty of bones, 
presenting scientists with an unprecedented opportunity to peer into the 
life and times of our hominid forebears. The discoveries have already 
proved revolutionary: the Georgian hominids are far more primitive in 
both anatomy and technology than expected, leaving experts wondering not 
only why early humans first ventured out of Africa but how. 
AdvertisementImage: GOURAM TSIBAKHASHVILI (fossils); CHRISTIAN SIDOR 
(New York College of Osteopathic Medicine (modern skull)
Sidebar: Skull SurprisesA Dubious Debut 
As the crow flies, the sleepy modern-day village of Dmanisi lies some 85 
kilometers southwest of the Georgian capital of Tbilisi and 20 
kilometers north of the country's border with Armenia, nestled in the 
lower Caucasus Mountains. During the Middle Ages, Dmanisi was one of the 
most prominent cities of the day and an important stop along the old 
Silk Road. The region has thus long intrigued archaeologists, who have 
been excavating the crumbling ruins of a medieval citadel there since 
the 1930s. The first hint that the site might also have a deeper 
significance came in 1983, when paleontologist Abesalom Vekua of the 
Georgian Academy of Sciences discovered in one of the grain storage pits 
the remains of a long-extinct rhinoceros. The holes dug by the citadel's

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
To Search in the Gambia-L archives, go to: http://maelstrom.stjohns.edu/CGI/wa.exe?S1=gambia-l
To contact the List Management, please send an e-mail to:
[log in to unmask]

To unsubscribe/subscribe or view archives of postings, go to the Gambia-L Web interface
at: http://maelstrom.stjohns.edu/archives/gambia-l.html

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~