Walking with Cavemen episode guide

The science of episode four: The Survivors

Homo heidelbergensis

Homo heidelbergensis is a transitional species. It possesses a range of anatomical features typical of different species of Homo and is thought to be the predecessor of both Neanderthals and modern humans. This hominid had a much bigger brain than Homo erectus, allowing it to plan complicated hunts.

Evidence for the Megaloceros hunting scene we show in the film came from throwing-spears found in Schöningen, Germany. Although lacking in imagination, it is highly likely that, like Neanderthals, heidelbergensis would have had a highly developed social brain and been able to communicate easily. They would also probably have displayed much the same sort of emotions as us.

Ice age

Between 700,000 and 800,000 years ago, cycles of climate change became more extreme. The amplitude of climate swings doubled between cold and warm periods every 100,000 years. Paleoclimatologists call this the mid-Pleistocene revolutions, which created dramatic variations in temperature.

Ice core evidence shows that at this time Africa was extremely dry. During the glacial maximum there would have been only tiny patches of forest left in Africa. Huge dust storms would come and go and, at times, would have been so severe they would have thrown dust high into the Earth’s atmosphere. Africa would have been a very inhospitable place to live.

	Homo neanderthalensis

Neanderthals

One of the most famous Neanderthal fossils was found at La Chapelle-Aux-Saints in France. It is the nearly complete skeleton of a largely toothless old man. Unfortunately, it was misinterpreted and came to symbolise the old-fashioned view of Neanderthals as shuffling, brutish cavemen – a complete misrepresentation of their anatomy, gait and intelligence. The growing consensus is that they were a highly successful species adapted to life in the cold.

Fossil evidence allows us to reconstruct the tough physical approach to life that the Neanderthals had. Their skeletons show many examples of traumatic lesions, breaks and post-traumatic degenerative changes, particularly head and neck damage. They show exactly the kind of trauma found in the bodies of rodeo riders, and this suggests many close encounters with large animals.

Modern humans

No agreement exists between palaeoanthropologists on exactly how to recognise ancient examples of 'modern' humans, morphologically or behaviourally. However, the majority of the fossil and genetic evidence favours an African origin for modern humans prior to 130,000 years ago. The earliest Homo sapiens skulls, for instance, have been found in Africa.

Although there are anatomical differences between Neanderthals and Homo sapiens, the key difference is in their minds, their cognitive thinking - such as making art and jewellery. Neanderthals saw and interacted with the world in a very different way to us.

Symbolism gave modern humans many advantages. For example the giving and receiving of gifts would have led to a highly complex social network – a web of alliances and friendships to fall back on. Through items of jewellery given as gifts, people were able to maintain friendships in their absence.

The bottleneck

The accelerated drying of the Africa environment would have a catastrophic effect on the anatomically modern humans who lived there. This is born out by the genetic evidence, which suggests that there was a dramatic population reduction at around this time – a bottleneck. This bottleneck is hard to pin down precisely, but some scientists argue that the changes which occur in the minds of anatomically-modern humans around this time had their origins in the squeeze in the population that occurred around 150,000 to 120,000 years ago.

As anatomically modern human populations in Africa shrank, (perhaps to as low as 10,000 individuals) the resilience and resourcefulness of those individuals would have been tested. Those anatomically modern humans best able to adapt and think their way out of their predicament would have survived. This concentration of ingenuity could have resulted in fundamental changes in the minds of the human population.