‘Green corridors’ led early humans out of Africa
Last updated on 9/17/2013 Print this page
11 September 2013
Early humans migrated through Africa along fertile river
systems which once flowed across the Sahara; new research from the
University of Hull suggests.
Above: Rivers in Africa, courtesy PLOS ONE.
Although it is widely accepted that modern humans (Homo sapiens)
evolved in Africa around 200,000 years ago, the route taken as they
travelled northwards towards Europe and South Asia remains a
For the first time, a team of researchers from the University of
Hull have been able to use a state-of-the-art computer modelling
system to reconstruct ancient rivers and past flood events that
would have strongly influenced the migratory routes of early
humans. The results show that around 125,000 years ago, three
rivers that have now dried up and are buried by dune-systems would
have linked mountains in central Africa to the Mediterranean.
Tom Coulthard, Professor of Physical Geography at the University
of Hull and lead author of the research paper, explained why these
rivers were likely to be crucial to the movement of early
“The rivers would have provided fertile corridors, a 1000km long
and up to 100km wide, which ran north across the Sahara, towards
“In particular, our simulations have identified one river that
appears to be the most likely route for human migration. The
Irharhar river linked mountain areas experiencing monsoonal
climates to temperate Mediterranean environments where food and
resources would have been abundant.
“Moreover, the high number of Middle Stone Age archaeological
sites that are concentrated around this region provide further
evidence that this river was especially important.”
The period of interest to the researchers happened before the
last ice age, when there was a dramatic increase in humidity in
what is now the Sahara Desert. For some time, this change in
climate is thought to have played a significant role in allowing
early humans to migrate out of Africa. However, this is the first
strong, quantitative evidence for the of presence three major river
systems that would have provided suitable routes for the dispersal
of early humans.
The full research
paper is published today in the journal PLOS ONE.
Although there is considerable evidence to show that humans
migrated across Africa as long as 125,000 years ago, the fate of
those early migrants is less well understood. Recent research
suggests that the ancestors of all humans living today left Africa
between 62,000 and 95,000 years ago.