The earlier post has generated a lot of interest and questions about the Neanderthals and their demise. So we have decided to spend some time in the next few posts describing the work that has been done in Gibraltar and our wider research looking at the bigger Eurasian picture of the Neanderthal distribution. The latest summary is in Clive Finlayson's book "The Humans who went Extinct" published in 2009 by Oxford University Press.
We will start by trying to understand who the Neanderthals were and, in future posts, zoom into Gibraltar which is where the last ones survived on this planet. The Neanderthals were humans. Some people consider them a separate species from our ancestors and others just a subspecies. Either way, they belonged to a lineage with a common ancestor to our own who lived some time around half-a-million years ago.
If you take a look at the map above, from an article written in the journal Trends in Ecology and Evolution by Clive Finlayson of the Gibraltar Museum and Jose Carrion of the University of Murcia, you will observe the maximum geographical distribution of the Neanderthals in red. They were clearly a Eurasian lineage of humans, with the southernmost part of their geographical distribution in Israel and Iberia. They weren't across this vast range all the time. During cold glacials their distribution was reduced to southerly refugia. Iberia was the major refugium. They had a permanent distribution in this peninsula, whether it was cold or warm. Contrast that with Germany where the Neanderthals only lived when the climate was mild.
This map, from the same paper, shows the southernmost limit of the cold fauna of the Ice Ages (dotted blue line). The Iberian Peninsula only saw the arrival of the cold fauna in extreme conditions. Even then the southerly limit was around the latitude of Madrid although some woolly mammoths did reach as far south as Granada. But the coastal south-west, from Malaga to Lisbon, with Gibraltar at the apex, never saw a woolly mammoth or woolly rhino. This is a first indication of how mild it was down here. More evidence will follow!
In this map, from a separate study of thousands of archaelogical sites by Clive Finlayson, we see that the last populations of Neanderthals were concentrated in four strongholds (1-4 in order of importance). The south of Iberia stands out as the largest stronghold and it is within this area that the last Neanderthals survived. We will explore why in the following blogs. But for now we leave you with one thought: so far we have not brought in our ancestors to this picture. For years, and some still cling on to this idea, it was thought that we were responsible for the Neanderthal extinction. So far we have been able to describe this extinction without having to bring our ancestors into the picture. More to follow...
Wonderful article, I'd never seen these maps before now, and didn't realise the Neanderthal people were so limited in their geographical scope. Honestly I thought they were a global people, so in fact they were the original Europeans.
ReplyDeleteHow large were their population groups, for example, is it possible to assess how many lived in Gibraltar at any one time, and was Gibraltar an important colony or only their last surviving colony. Similarly, there would have been no borders in those days, so would these people have hunted in the Campo de Gibraltar, or even further afield.
Regarding the rest of Iberia, how scattered were the various groups, I'm thinking that to avoid interbreeding in small groups they would have to socialise to some extent with other groups, so how would they do that if their populations were small and widely dispersed?
Thank you for this most interesting treatise. I, too, thought that we were direct descendants of the Neanderthals. Looking forward to the next episode!
ReplyDeletethank you for your comments and questions. Judging from the space available to them in the caves we think that group sizes could not have exceeded 15-20 individuals. They may have lived in family groups. We don't know how many shared a territory or home range but we have an idea of range size.
ReplyDeleteWe've studied where the raw materials (rock types) used to make their tools came from. Nearly all are found on the Rock but one type came from a quarry they had in the Palmones River about 17 kilometres away. So a distance in a straight line of 20 km seems reasonable as a minimum. So they could have had a home range of 20x20, ie 400 square kilometres. So they weren't pinned down on the Rock!
We also think this was a key to their success and also their demise. They lived in ecologically diverse landscapes so they could find lots of food types in a small area. But when their populations became fragmented they had problems of connectivity and probably suffered from inbreeding. Anyway I will add more in future posts!
Clive
Just read a brief article on the CBC website in Canada about Ed Green of the University of California, finding some evidence of dna traces of neanderthals in modern humans . Any idea how this might fit in. I'm not a scientist just interested.
ReplyDeleteStuart