Like many thousands of others I intend to visit painted caves in France during my next holiday. The prospect is thrilling because it is almost 20 years since I last looked at the horses, bison and reindeer depicted in Lascaux and other caves by ice-age artists.
I particularly want to visit Pech Merle, a cave near Cahors, in which a spectacular panel of painted horses was created around 20,000 BC, when the last Ice Age was at its peak. Although the cave has electric lights, my mind will see animal-fat lamps burning on the floor, with one held aloft by a young boy to illuminate the quick movements of the artist's hand. The artist, an old, sprightly man with long grey hair, naked but with painted skin, is part of a community who live by reindeer hunting on the tundra that covered southern France at that time. Amid the lamps is his paint: lumps of red ochre crushed to powder and mixed in a wooden bowl with water from the cave floor. His tools are sticks of charcoal, pieces of leather and fur, frayed sticks and hair brushes. The air is sweet from herbs smouldering on a fire. Every few moments the artist kneels and inhales deeply to refresh the vision of galloping horses in his mind.
I will imagine the painting half complete - the horses depicted in profile, back to back with their hindquarters overlapping. The artist takes mouthfuls of paint and spits them out through leather stencils to make spots within the outlines. His breath is the key ingredient to make the horses come alive.
In the few minutes while the Peche Merle guide describes the painting, the artist in my mind will have worked for several hours, pausing only to change his pigment or stencil, to switch a brush or sponge, to replenish the fat in his lamps and to intoxicate his mind. He will have talked and sung to the horses, dropped on all fours and reared like a stallion. And when the guide leads the tour party out of the cave, I will turn for a last look at the painting, to see the artist lying, physically exhausted and mentally drained, on the floor.
To imagine that 20,000-year-old scene in Pech Merle, my mind will draw on meticulous studies by archaeologists of the painting itself, identifying how the pigments were produced and applied. I will remember accounts I've read of how Aboriginal Australians and South African Bushmen produced rock art during the 19th century, often taking herbal drugs to put their minds into "altered states of consciousness", and painted their visions of the supernatural world.
Translating ancient remains into scenarios of past lives is perhaps the greatest challenge facing prehistoric archaeologists. We lack written records such as diaries and letters. Organic materials seldom survive: no food remains, no wooden or woven artefacts, or clothing made from hides, supplement the stone tools that are so resistant to decay. Nevertheless, with new scientific techniques, archaeologists are gaining an ever more detailed picture of how people lived when the last Ice Age was at its height.
Those who painted in Pech Merle lived in a world very different to ours today. Ice sheets that reached several kilometres thick covered much of the northern hemisphere, including northern Britain. Southern England was part of a continuous polar desert that extended across northern Europe, as neither the English Channel nor the North Sea existed. In Africa, Asia and Australia, the deserts were far larger than today because of widespread drought as well as cold. Although much of the planet was uninhabitable, some regions had abundant game, especially in North America where an exotic array of huge mammals grazed in open woodland - mammoths, giant ground sloths, camels and sabre-toothed tigers - safe from human hunters, as no human being had yet set foot on American soil.
Cave paintings were just one of the cultural achievements of ice-age communities. Those who lived on the Russian Plain, in modern-day Ukraine, created the first architecture known to humankind - dwellings made from mammoth bones. Several of these were clustered together to make small villages, one of which is known today as Pushkari. Let me take you back to 20,000 BC for a brief look around the village.
Five dwellings form a rough circle on the tundra. They face south, away from the biting icy wind and close to a meander of the semi-frozen river.
Each dwelling is built from mammoth bone to make an igloo shape, with two tusks up-ended to form an imposing entrance arch. The vertical supports for the walls are massive leg bones, between which jaw bones have been stacked, chin down, to create a thick barrier to the cold and wind. Further tusks laid on the roof weigh down hides and sods of turf. Smoke seeps gently from the roof of one dwelling; the cries of a baby pierce the thick hide of another.
Beyond the village, a sledge loaded with massive bones is being hauled from the river. The faces of those working are misted in clouds of hot breath, behind which thick beards and long hair leave little flesh exposed. They are wrapped in fur-lined clothes - no simple draping of hides but artfully stitched clothing. This village is no more than 250km south of the glaciers. There are nine months of winter to endure and temperatures can fall to minus 30xC. The river supplies building materials: bones from animals that have died in the north, their carcasses washed downstream.
Life is tough: hauling bones, building and repairing dwellings, cutting and breaking tusks into sections so that village craftsmen can make utensils, weapons and jewellery. Daylight is precious - a few hours each day, then long hours of darkness, spent telling stories around the fires. A small fire is burning between the huts. The flame from a single knotted log provides a focus for half a dozen men and women who sit close together, knees drawn up, to minimise exposure to the wind while they stitch new clothing.
Near the fire a reindeer is being butchered and the air stinks of flesh and blood. It was found wandering in isolation from its herd - a welcome surprise for a party who had been collecting stone from a nearby outcrop.
Now they can eat meat without depleting the store in their freezer - a hole in the ground. None of the carcass will be wasted. The meat will be shared between the five families living at Pushkari this winter. Knife-handles and harpoons will be made from the antlers, clothing and bags from the hide, and the ligaments and sinews will provide thread and cord. The heart, lungs, liver and other organs will be eaten as delicacies, the teeth drilled to make pendants, the bone saved for fuel.
One of the dwellings is lit by the small flame from an animal-fat lamp. It is warm, stuffy and dingy inside. The floor is soft, carpeted with hides and furs that surround a central ash-filled hearth. Mammoth skulls and leg bones provide furniture; an assortment of leather bags, bowls made from bone and wood, antler and stone tools are scattered by the walls and hung from the rafters - a scene of stone-age domestic clutter. The flickering light exposes a man's face. He looks old, but skin and bone age rapidly in this world. His hair is in plaits and he has pendants of ivory and pierced teeth around his neck. His fingers work quickly with a needle and sinew thread.
Outside the dwelling, a man, a woman and some children sit together while striking nodules of stone that rest on their knees. Flakes of stone are detached, the largest carefully laid to one side for later use as a utensil or spear head; others are left where they fall or casually tossed into the scatter of surrounding flakes. There is chatter and occasional laughter; some cursing as a thumb rather than a stone is struck.
Another dwelling lacks any sign of domestic life. Its floor is covered in thick furs; a particularly large mammoth skull dominates the room, painted with red stripes, alongside bone drumsticks and flutes made from bird bone.
Two ivory figurines, each no more than a few centimetres long, rest on a stone slab. This is where special gatherings take place: when visitors arrive, almost the entire village meets inside so that news and gifts can be exchanged. It gets pretty hot and smelly; noisy, too, when they all begin to sing.
But now the only sound is that of daily life - the crack of stone against stone, the chatter of voices, the huffing and puffing from hard labour.
These are carried across the tundra by the icy, relentless wind, one that will bring the howling of wolves as darkness descends. After dark, the villagers cluster around a fire. Roasted meat has been shared, stories told. The temperature crosses a threshold and people seek out the comfort of furs.
Life at the height of the Ice Age was not as challenging everywhere as that at Pushkari or on the tundras of southern France. People were ambushing antelopes on the African savannah, stalking wallabies on the grasslands of Tasmania, fishing in the Mediterranean and the Nile. One archaeological site that shows a less demanding Ice-Age life is Ohalo, on the edge of the Sea of Galilee. This is normally submerged; the remnants of brushwood huts are exposed only when drought hits the Jordan valley and the lake waters fall. This happened in 1989, when the site was first discovered, and again in 1999 when I was travelling in Israel and visited the excavation being directed by Professor Dani Nadel of Haifa University.
It was one of the most idyllic excavations I had ever seen: hot sun, glistening blue water and large, shaded trenches revealing the debris of ancient lives. The preservation of plant remains and animal bones was excellent. The meticulous work by Dani Nadel and his colleagues has provided another vision of ice-age life: brushwood dwellings in oak woodland; a new hut under construction - cut saplings, forced into the ground, are being woven together to make a dome. The work is much easier than that at Pushkari - indeed, life at Ohalo seems more attractive in every way. When I think of Ohalo, I see many people scattered along the lake shore: groups sitting and chatting; children playing games; old men sleeping in the afternoon sun. Some women hang nets to dry across coracles, while another approaches the huts from the water's edge bearing a basket of freshly caught fish. Children follow her into a dwelling where the fish will be threaded on to twine and hung to dry.
Two women emerge from the woodland, draped with freshly killed fox and hare. Several men follow with a trussed-up gazelle supported on a pole.
Women and children appear with bags and baskets - on their heads, hauled along the ground, slung across shoulders or tied around the waist. The carcasses are placed close to a hearth and piles of fruits, seeds, leaves, roots, bark and stems are tipped out on to hides. There will be a feast tonight, perhaps the last, as the settlement burned down soon after 20,000 BC. Whether this was accidental, or a deliberate burning of huts to get rid of fleas and lice, we do not know, but the intense fire charred and hence preserved many bones and plants that would otherwise have rotted away.
Turning archaeological artefacts into images of daily life in prehistory is a considerable challenge. To do it properly, one must make a thorough and exhaustive study of the remains, or the reconstructed scenes are just another form of fiction. It would be fascinating if it were possible to build a time machine so that we could visit the living settlements; the nearest I could get to this was to write a book. Through the eyes of an imaginary traveller, After the Ice tells the story of life at sites such as Pech Merle and Pushkari, during the peak of the Ice Age and through the following 15,000 years of human prehistory - a period of rapid global warming, when the ice sheets melted, the sea level rose and thick woodland replaced tundra. The descendants of the reindeer hunters and artists of the French caves spread into northern Europe to live in the new woodlands as hunters of deer and wild boar.
Around 9500 BC,in the Jordan valley, the successors of the people of Ohalo invented farming, at settlements such as Jericho. Within a few thousand years, farming had spread to China, New Guinea, Mexico and the Andes, and into Europe, south Asia and north Africa.
The origin of farming, between 20,000 and 5000 BC, was of such momentous importance for human society. It laid the basis for the early civilisations, and indeed for the modern world. In 20,000 BC, all communities lived as hunter-gatherers and were excluded from many regions of the world by harsh conditions. By 5000 BC, many were living by farming; some growing wheat and barley, others rice, taro and squash. Some lived by herding animals, some by trade and others by craftwork. Permanent villages and towns had replaced temporary camp sites; mammoths had been replaced with domesticated sheep and cattle. People inhabited land from Tierra del Fuego, the southern-most tip of South America, to the Arctic, from the Amazonian rainforest to the Australian desert. Many still lived as hunter-gatherers, but in Mesopotamia towns had grown so large and complex that the first true civilisation was about to appear.
My task as an archaeologist is to reconstruct prehistoric settlements and explain why, where and when changes in human society occurred. My excavations are in Wadi Faynan, southern Jordan, where there are remnants of dwellings that had been inhabited in 9500 BC by people who made the transition to farming, hunting wild goats and cultivating barley on the banks of a nearby river. We have found burial sites, stone tools, shell and stone beads, and carvings.
It is thrilling to discover such artefacts, but it can also be deeply frustrating, as I would dearly like to know the identities of people whose bones we find. There is a great deal about their lives that we will never know. But we can combine archaeological evidence with imaginative insights, supported by anthropological studies of recent hunter-gatherers and subsistence farmers, to take a journey through prehistory.
Steven Mithen is professor of early prehistory and head of the school of human and environmental sciences at the University of Reading. His book, After the Ice: A Global Human History 20,000-5000BC is published by Weidenfeld amp; Nicholson