It's 3.5 million years ago and in East Africa a remarkable species of ape roams the land. Australopithecus afarensis has taken the first tentative steps towards humanity by standing and walking on two legs.
Just a few million years previously, Africa was covered, almost edge-to-edge, with dense rain forest. Our ancestors almost certainly used all four limbs to move and live and hunt in their tree-top homes. But massive geological turmoil changed their destiny.
The rift valley was forming, and the rain forests dying as Africa dried out - turning the landscape into a mosaic of scattered trees and grass. In this new environment afarensis found it more efficient to move about on two legs rather than four.
This film follows a close-knit troop of afarensis, and in particular, Lucy and her young infant. Led by a strong alpha male, there is harmony in their lives. They sleep high in the trees and spend most of the day foraging for food. But then tragedy strikes. While drinking from a nearby river, a lone crocodile sneaks in unnoticed and catches the alpha male unawares.
Now leaderless, a dispute for dominance between the two secondary males unsettles the troupe. Added to that, a rival troupe invades Lucy's territory. While not uncommon in their chimp-like lifestyles, the resultant turf war is both violent and extreme and has devastating consequences.
As the troop's life moves on, 'First Ancestors' shows how although bi-pedalism offers only slight advantages to the afarensis, it opens the door to an astonishing set of new skills and abilities that will change the shape of human life on Earth forever.
Why did we choose to begin our story with afarensis?
Our story begins around 3.5 million years ago in Ethiopia. As one of the first species of upright walking bipedal apes, we featured Australopithecus afarensis in our opening story because this is certainly the best-documented early hominid. (‘Hominid’ is the name we give to the upright walking ape-like ancestors of humans.)
The female afarensis known by scientists as Lucy (find AL288-1) has now become a celebrity fossil. It contains 47 out of 206 bones in a full skeleton, which might not sound that impressive, but in the world of palaeoanthropology it is outstanding.
We can deduce a fair amount about the group make-up of afarensis from a famous fossil discovery AL333, known as The First Family. Found by Michael Bush in 1975, this discovery comprises the remains of at least 13 individuals that were buried in a catastrophic event, possibly a flood. The group appears to have been related to each other. This collection provides unique insights into the structure and biology of this species.
How did we model afarensis' behaviour?
The fossil evidence gives us some clues about afarensis' social life, but to help build up a more complete outline we have tried to model their behaviour on that of chimpanzees, because they are closely related to early hominids.
Jane Goodall's work at Gombe, Tanzania, is invaluable in outlining the complex political world of these extraordinary social animals. She has documented chimpanzees' complicated hierarchies of dominance, display behaviour and male/female relationships.
Our key storyline, the territorial disputes between Lucy's group and a neighbouring troop, is based largely on actual chimpanzee observations. Goodall writes of one incident where a group of patrolling chimps encounter a female with an infant. One of the males seized the stranger, hit and bit her, before stamping on her back. During the fierce assault, another male seized the infant and charged off through the bushes. In this way the males of a troop protect food resources for their own females and young.
What do we know about the common ancestor?
Genetic evidence suggests that chimps and upright walking ape ancestors diverged from a common ancestor between 5 and 7 million years ago. Fossils of this mysterious creature have never been found, as the dense forest environments that would have been its home do not preserve fossil remains well. Like living apes that are adapted to living in the forest, the common ancestor probably walked on its knuckles.
The changing climate and environment
Many experts believe that the key to the creation of the broken, mixed environment of trees, shrubs and savannah grasslands in Africa in which afarensis evolved, is the monsoon. Many millions of years ago, India collided with the continent of Asia, buckling the surface of the Earth to create the huge mountain range that we call the Himalayas.
This geological event created a monsoon that released vast quantities of rain, drying out the air. This same air flows across East Africa, and causes rainfall to drop sharply, drying the rain forests and replacing them with broken scrub and woodland. It is no coincidence that the monsoon intensified 6-8 million years ago - the time at which the common ancestor lived.
So why did bipedal apes emerge in this environment?
Paleoanthropologists have advanced many theories over the years as to why quadrapedal (four-legged) apes began walking upright. One of the most recent, and persuasive, theories has been suggested by Dr Patricia Kramer of the University of Washington, who believes that bipedalism was the most energy-efficient way of moving around the broken landscape that appeared in Africa between 6 and 8 million years ago.
Energy is simply too critical a commodity to waste if you are a primate living a marginal existence in the African savannah. Its conservation becomes critical. Dr Kramer found that the short-legged morphology of early bipeds was the most energy-efficient body shape for covering relatively long daily distances on the ground. Once bipedalism took hold, there was no looking back.
Professor Robert Winston meets Lucy, the first upright ape, and follows her ancestors on the three-million-year journey to civilisation. Broadcast in 2003, Walking with Cavemen combined special effects with the latest scientific theories, to show us what it really means to be human.
In the previous Walking with... documentaries, extinct animals were recreated with CGI and animatronics. For Walking with Cavemen, a slightly different approach was taken. While most of the animals depicted were still computer generated or animatronic, the human ancestors were portrayed by actors wearing makeup and prosthetics, giving them a more realistic look and permitting the actors to give the creatures a human quality.
Like its predecessors, Walking with Cavemen is made in the style of a wildlife documentary, featuring a voice-over narrator (Robert Winston in the British release, Alec Baldwin in the North American release) who describes the recreations of the prehistoric past as if they were real. As with the predecessors, this approach necessitated the presentation of speculation as if it were fact, and some of the statements made about the behaviour of the creatures are more open to question than the documentary may indicate.
Each species segment takes the form of a short drama featuring a group of the particular hominid in question going about their daily lives (the search for food, protecting territory, and caring for the sick and injured). The intent is to get the human viewer to feel for the creatures being examined, almost to imagine being one of them (a trait that the documentary links to the modern human brain).
Episode One: "First Ancestors"
In the first episode, we see Australopithecus afarensis, and focus on their evolved bipedality (walking on just rear feet - our legs). More specifically, the story follows the famous Lucy and her relatives, as they first develop a leadership conflict following the death of the alpha male due to a crocodile attack, and then are attacked by a rival troupe. The attack ends with death of Lucy herself, and her eldest daughter caring for Lucy's now-orphaned baby (her sibling), as a sign of the developing humanity in these "apemen".
Time: 3.2 Million Years Ago
* Australopithecus afarensis
Episode Two: "Blood Brothers"
The second episode leaps forward to a time when Paranthropus boisei, Homo habilis and Homo rudolfensis co-exist. H. habilis is depicted as an intelligent omnivore that is more adaptable than the herbivorous P. boisei. The two species are contrasted, with H. habilis being "a jack of all trades", while P. boisei are "a master of one" - i.e. they are specialized herbivores while H. habilis are generalized omnivores. Consequently, though P. boisei are able to eat termites, tall grasses and hard acacia pods in difficult times, they will not be able to survive in the future, when at the beginning of the next Ice Age the climate will change, and these plants will be gone for good. H. habilis, on the contrary, have become smart by eating carrion and bone marrow among other things, and evolving a basic social behavior, which is more firm than that of P. boisei, will continue to survive, until it evolves into Homo ergaster, seen in the next episode, who has developed these traits to a greater extent.
The episode also briefly shows the H. rudolfensis, remarking that albeit they are taller, they are very similar to the H. habilis.
Time: 2 Million Years Ago
Place: East Africa
* Paranthropus boisei
* Homo habilis
* Homo rudolfensis
Episode Three: "Savage Family"
In the third episode, Homo ergaster is depicted as the first creature to master the art of tracking. This was made possible because their diet has grown increasingly more carnivorous, and the nutrients in meat made them even smarter than H. habilis of the previous episode. They also begin to form into tribal societies, with genuine bonds between their men and women, though violence is still occurring.
The episode later shows H. ergaster spreading into Asia, becoming Homo erectus and encountering the enormous herbivorous ape Gigantopithecus, "the original King Kong".
However, for the next million years, H. ergaster is still very much an animal, following its instinct, but then, they are shown harnessing fire and beginning to break-away from their direct dependence on their environment. (This ties neatly into the next and final episode, which is centered on human mind and imagination.)
Time: 1.5 Million Years Ago - 500 000 Years Ago
Place: Southern Africa - China
* Homo ergaster
* Homo erectus
Episode Four: "The Survivors"
The fourth episode talks about the mental evolution of the humanity, as opposed to the physical in previous ones. First we leap forward to a time when Homo heidelbergensis is living in Great Britain. H. Heidelbergensis is depicted as intelligent and sensitive but lacking in the ability to comprehend an afterlife, or anything that isn't in the "here and now".
Next, the episode shows a life of a clan Homo neanderthalensis, how they lived and hunted, including the mighty mammoth during the latest Ice age. They are intelligent but still lack the imagination of modern humans.
Finally, we see modern Homo sapiens (represented by Bushmen) in Africa, who had to become imaginative and inventive to survive the long drought, and finally glimpse the cave painters of Europe, who had "evolved" the idea of the afterlife and the supernatural, and who are now ready to start the human history as it is now known (and drive-out the Neanderthals to extinction).
Time: 200 000 Years Ago - 150 000 Years Ago
Place: Europe - Africa
* Homo heidelbergensis
* Homo sapiens