The Kebara Cave was an archaeological site lying on the southern edge of the Carmel Range, a series of limestone hills that rise out of the Mediterranean on the southern flank of the city of Haifa in Israel, part of the Levant, a small habitable zone that lay between the Mediterranean and the Arabian deserts, linking the two great landmasses of Africa and Eurasia.
About a million years ago a huge expansion of the habitat of African animals took place when climatic change transformed the northern part of the continent’s ecosystem into a vast savannah, favouring the free movement of animals across a vast new territory. By extension this territory included the Levant, a vital crossroad between the African and Eurasian landmasses.
Amongst the creatures that spread into the Levant and beyond were man’s early ancestors Homo erectus and over a long period of time these early men spread out northwards gradually populating a large part of Europe, where they evolved into Homo neanderthalis. Over the same period of time African erectus evolved and Homo sapiens appeared in the north east corner of the continent.
The climate, however, did not stand still and continuing its relentless cycle of change the planet became colder and drier. In Europe the glaciers reached far south whilst Africa became drier pushing their respective early human populations towards a central temperate zone. In the Levant climate fluctuated throughout the Middle Palaeolithic, going from warm and dry to cold and wet, which was in any case favourable to man compared to the harsh conditions in the north and south.
Fossil evidence discovered at Kebara Cave and other sites in Israel clearly shows that Homo neanderthalis from the north and early Homo sapiens from the south met and cohabited in Levant.
Shlomo Wald took the coastal road to Haifa, it was snarled up as usual and once it got going most of the drivers seemed bent on suicide. The country was small, very small and there was no way out, it was more like an island; to the north Lebanon with the Hezbollah at the frontier, to the east Syria, still in a state of war with Israel, a little further to the south Jordan tried to live with its difficult neighbour and directly south the Sinai Desert and Egypt.
From what Ennis could see the country’s history was a story of permanent conflict and from what Shlomo Wald had told him as he struggled through the traffic it was just the same in distant prehistoric times.
‘These caves are about twenty kilometres south of Haifa,” Shlomo explained, “they were first excavated in the twenties and thirties, then after the declaration of the State of Israel digs were started again in the late sixties.’
‘I believe the Tabun Cave excavation has one of the longest sequences of human occupation in the Levant?’ asked Ennis
‘That’s right, over a long period the climate changed, sometimes relatively warm climate when glaciers covered large parts of the world melted and sea levels rose. So the coastline here receded and the coastal plain you now see was much narrower, covered with savannah type vegetation. When the glaciers returned, the sea level to drop by about one hundred metres, so the coastal plain became wider and was covered by dense forests and swamps. There are in fact several caves, the Tabun Cave contains a Neanderthal-type burial dating to about 120,000 years ago, one of the oldest found in Israel. Then there is the Skhul Cave.’
‘An appropriate name,’ said Pierre laughing.
‘Yes, but not in the sense you imagine, it actually means the ‘Childrens’ Cave, where a total of fourteen fossilised skeletons were found.’
‘Archaic Homo sapiens,’ added Pierre.
The Kebara Cave was situated above a banana plantation on the western slope of the Carmel Mountains that lay to the right as they continued the coast road. Shlomo explained it had been the site of decades of continued archaeological excavations, where anthropologists and other specialists worked at uncovering the past when neanderthalis and modern type sapiens occupied the same territory between about 25,000 and 50,000 years ago. Ennis could not help thinking how little things had changed and could not help wondering about the kind of warfare that had been used in the confrontation between two species.
Shlomo had a better explanation; each species occupied its own ecological niche, implying the two species could have coexisted. The theory didn’t hold, as the same set of stone tools was found at Kebara and two other sites, Qafez and Skhul, occupied either by neanderthalis or sapiens, meaning they would have certainly competed for the same food and game in the same territory.
The question that excited anthropologists was; did they interbreed? For Shlomo it seemed unlikely, he saw no sign of convergence between the two species, neither neanderthalis nor the modern type sapiens at Qafez and Skhul changed, as they would have if there had been interbreeding, and hybrid offspring.
Why though? The logical answer was; they did not interbreed because they could not, they were incompatible, two distinct species of humans with parallel lives, as Homo sapiens and Homo erectus in Borneo.
‘How do you define a species then?’ asked Ennis.
‘Well John, the biologist Ernst Mayer put it this way, “Species are groups of actually or potentially interbreeding natural populations that are reproductively isolated from other such groups.”’
‘So a species can only reproduce with its own.’
‘That’s it in a nutshell! Neanderthals evolved into a different species in the same way as all other species have always evolved in nature, influenced by geographically isolation and a changing habitat that favoured certain mutations.’