There were giants on the earth in those days ...

... and also afterward, when the sons of God came in to the daughters of men, and they bore children to them. Those were the mighty men who were of old, men of renown.

-Genesis 6:4

The earliest humans (homo sapiens to be exact) would have lived contemporaneous with at least one other creature that looked remarkably like us.  We now refer to them as Neanderthals and there is a great deal of debate on the nature of our relationship with them.  Some believe we have treated them rather poorly and subdued them into extinction. Others say we simply outwitted them with superior intelligence and tools. While others believe we have mated with them and produced sterile hybrids. Still others believe that they were our ancestors.

Gerald Schroeder is a physicist and an Orthodox Jew who had written several books arguing that science and the Bible are not at odds concerning the origin of humanity, life, and the universe. In the Science of God, for example, he presents a compelling argument that the events following the Big Bang and those of the first six days of Genesis 1 are, in fact, identical realities described in vastly different terms.  Dr. Schroeder also argues that the Neanderthal, or the children of Neanderthal/homo sapien unions, are the 'giants' mentioned in Genesis 6:4.  The word that the original Hebrew Bible uses is actually 'Nephilim,' which loosely, and somewhat inaccurately, translates to 'giants.'

Svante Paabo is the director of the department of evolutionary genetics at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. Researchers from his lab recently discovered that modern Europeans and Asians share between 1 and 4 per cent of their DNA with Neanderthals – but Africans don’t. This tell us that the Neanderthal have indeed 'come into' us, but any interbreeding between us and them happened after modern humans had left Africa, but before they spread across Asia and Europe

Humans first encountered Neanderthals in the Middle East, shortly before the second great migration out of Africa.  The Great Lakes region of East Africa is part of a geological formation know as the Great Rift Valley. Just north of Lake Turkana, one the northernmost lakes, is the Ethiopian highlands, and here the Great Rift Valley diverts eastward slightly into the Red Sea and from there into the Jordan River valley in Palestine. This is likely the path that humans took on their way out of Africa.

They met the Neanderthal  perhaps as early as 80,000 years ago. From 80,000 years ago until about 30,000 years ago, humans and Neanderthals lived side by side. There are caves in the Mt. Camel region of Israel that show evidence of human and Neanderthal intermingling.  A few Neanderthals may have infiltrated a group of humans, and started interbreeding, rather than a mass mixing of the two species.  We don’t know why they kept themselves mostly separate, but perhaps there were significant cultural differences.

 A team of researchers led by Svante Paabo previously made news in 1997 by collecting and analyzed the mitochondrial DNA of Neanderthals, and, at first glance, the data supported the notion that there was no interbreeding between humans and Neanderthals.

You may now be asking, doesn't this finding contradict the recent mitochondrial Eve finding that all humans are descendant from a small group of humans that existed 200,000 years in East Africa?  The answer would be, not really.  One also may be tempted to argue that since people of European descent have 'caveman' genes, they are therefore more inferior to the more purely homo sapien Africans (and given all the solipsist arguments that Europeans tried making about the inferiority of Africans, perhaps a little chagrin is deserved).  However, the amount of Neanderthal DNA in Europeans and some Asians appears to be quite small and probably does not have much of a functional effect, but stay tuned.  Perhaps there will more to this story. People of Europeans descent, however, need not be too distraught because Neanderthal turn out not be as intellectually challenged as they are often stereotyped to be.

Fossilized bones of Neanderthals were first discovered in 1856, in the valley of the Neander River in western Germany (Neander Valley is Neanderthal in German). Their skulls were distinctly less human than our own.  They had pronounced eyebrow ridges, large teeth, protruding jaws, and receding foreheads and chins. Neanderthals lived mostly in Europe and colder parts of East Asia, the southernmost boundary being the area around Palestine. They lived during glacial times and hunted mammoth, the woolly rhinoceros, and the giant cave bear.

They were the first animals to bury their dead, thus preserving them from scavengers.  This tends to show that they valued life, felt affection, and cared for individuals.  Sometimes the dead were old and crippled and could only have lived as long as they did with the loving help of others in the group.

What's more, food and flowers were often buried with the corpse, and this seems to indicate that Neanderthals felt life continued on an individual basis after death.  If they felt that there was life after death, then this might indicate that first stirrings of what we can call religion (or science)--a feeling that there is more to the Universe than is apparent to the senses.