The Incredible Human Journey

by Alice Roberts

  The sample from the southern end of Haida Gwaii, from a site above sea level, showed that sedges also dominated the early plant life there, but that there were lots of other herbs and shrubs as well. Some of these plants, like ferns, prefer warm, moist habitats, whereas others, such as crowberry and bearberry, survive in cold, dry places. This mixture of plants is similar to that found in the coastal tundra of modern south-western Alaska. The concentration of pollen grains in the sample gradually increased over time, as the plants gained a firm foothold on the post-glacial landscape. By 15,600 years ago, the first trees, lodgepole pines (Pinus contorta), had arrived and the environment of the islands changed from tundra to pine woodlands with ferns covering the ground between them. Pine pollen can blow a long way, but the presence of this species on the islands was also confirmed by radiocarbon dating of a lodgepole pine needle to just over 14,000 years ago. Other coastal sites in British Columbia have shown pine woodland to be widespread by about 14,000 years ago. As the climate grew even warmer, the succession of plants continued: the pine woodlands started to disappear, to be replaced by spruces.2

  ‘People could have travelled down the coast, probably by boat, from oasis to little oasis. The environment was certainly suitable for humans, but we’ll leave it to the archaeologists to find the hard evidence that they were actually there.’

  After lunch in one of the pleasantly wooded courtyards of Simon Fraser University, I explored the campus. The original sixties buildings were designed by architects Arthur Erickson and Geoff Massey, and the modernist design principles have been maintained in later buildings, so that the whole scholarly city has a stylistic coherence and grace. I sat down to read in the calm serenity of the Academic Quadrangle, where a huge jade boulder was reflected in the still waters of a pond. The monumental buildings had a lightness and aesthetic appeal that I didn’t normally associate with sixties concrete architecture. Their futuristic qualities had made them the ideal backdrop for sci-fi series: James Fraser University has featured in The X-files, Stargate, and as a city in the Cylon-occupied planet of Caprica in the film Battlestar Galactica.

  Back in Ice Age Canada, though, and aliens aside, British Columbia held other clues to the potential coastal dispersal of its earliest human inhabitants. Bizarre as it may seem, but very fitting for Canada, one of those clues is bears. The Haida Gwaii Islands are full of limestone and are rained on a lot: perfect conditions for cave formation. Limestone caves are particularly good for fossil preservation, and so the Haida Gwaii caves seemed like a pretty good place to start looking for fossils. In 2000, a team of Canadian palaeontologists and archaeologists started excavating the caves – and quickly started to find animal bones. These included dog, mouse deer, duck – and bear. Radiocarbon dating showed the dog bones to be quite recent in palaeontological terms: less than 2000 years old. But the bear bones were very exciting – they were much older.3

  I travelled north from Vancouver, taking the ‘Sea to Sky’ Highway along the magnificent coast of Howe Sound up to Squamish, then winding through the wooded gorges of the Cheakamus River valley to Whistler. This ski resort – in summertime – was full of holiday-makers going mountain-biking, whitewater-rafting, and shopping. But that day Whistler also hosted archaeologist Quentin Mackie, who had kindly arranged to come down from the University of Victoria especially to meet me, and he had brought along a couple of old friends: two bear skulls from excavations on Haida Gwaii.

  When I arrived in Whistler, Quentin Mackie was already there, in the foyer of the hotel, with the two bear skulls on a coffee table in front of him (I wondered what the other hotel guests thought of this). The skulls were different sizes – one was a brown bear, the other a black bear – but both looked formidable beasts. They were ancient specimens, excavated from caves on Haida Gwaii.

  ‘These are just a couple of the specimens we’ve discovered in the caves,’ explained Quentin. ‘We’ve found more than six thousand bear bones, from black and brown bear, and some of them date to as early as 17,000 years ago.’

  So, very soon after the peak of the last Ice Age, Haida Gwaii was supporting not only sedges and grasses, but large – very large – mammals.

  ‘We were really surprised to get this early date, because conventional wisdom suggested that, at that time, there would have been nowhere for bears to live on the north-west coast: it would have been covered by ice. There was some pollen evidence for ice-free areas, but we thought that these were small, very windswept, perhaps not very viable environments.’

  ‘How do you think the bears got there, that long ago?’ I asked.

  ‘With these early dates we have to consider one of two possibilities. Either these bears were able to get into the coast from somewhere [north] very early – as early as 17,000 years ago, or they spent the last part of the glaciation on the coast, in some kind of refugium. Both of those are really interesting – because if bears could get in early or if bears could survive through the LGM on the coast, then it implies that humans could have done as well.’

  I could see Quentin’s point – that the presence of a large mammal in Haida Gwaii might have implications for human migrations3 – but I was also a little sceptical.

  ‘But you haven’t found any evidence of humans that long ago?’

  ‘Well, no. But the interesting thing about these bears is that they make a pretty good analogy for humans. They’re large land mammals, they’re quite territorial, and they’re omnivorous. They eat berries, roots, insects, even small mammals like ground squirrel – and they may even chase down deer and caribou. They’re also very good beachcombers. They will go along the strand line – and I’ve seen them do this many times – roll over rocks and lick up sand hoppers and crabs. But they’re also quite capable of taking migrating salmon from rivers.

  ‘Humans would have been able to eat pretty much anything that a bear would eat … so I think that if it was a good environment for bears – which it clearly was – then it was a great environment for humans.’

  Quentin had found some evidence of human activity dating back to 13,000 years ago. It seemed that people had been hunting the hibernating bears at that time, which sounded like a highly dangerous pursuit, but Quentin said there were historical accounts of people waking hibernating bears with burning braziers, then waiting by the cave mouth to spear the angry animal as it emerged.

  ‘Bear meat is quite edible. I’ve eaten it myself. If you cook it well it’s delicious, and very nutritious. The bears’ winter pelts would also have been extremely valuable to these people, and we also have a really good record of them making tools out of bear bones, so it’s a fabulous resource from nose to tail.’

  However, these bear hunters weren’t early enough to have been among the first colonisers of the Americas. But Quentin was not about to give up the search.

  ‘These caves are still some of the oldest sites in Canada. And we feel fairly confident that in the next few years we’ll be able to push that date back a little bit.’

  The mitochondrial genetic lineages of brown bears have also been investigated – including mtDNA from bears preserved in permafrost – and they tell us something very interesting. It seems that brown bears, like humans, came through Beringia – and had persisted there throughout the LGM.4 Not only that, the mtDNA of brown bears suggests that, having survived in refugia on islands off the western coast of Canada, these formidable animals went on to repopulate the mainland from about 13,000 years ago.

  I missed out on seeing actual bears in Canada (although I did see a whole bear skeleton in a gem shop window), but I did get to visit a remnant of the Great Cordilleran ice sheet: the Ipsoot glacier, high in the mountains above Pemberton, near Whistler. A helicopter dropped me off on the glacier, along with mountaineer Jim Orava, and I spent a thoroughly enjoyable day learning to ice-climb. Equipped with ice axes and crampons, we crawled over the glacier – climbing and traversing vertical walls of ice, leaping over crevasses with ropes for security. I had rock-climbed before, but it wa
s a very different sort of climbing on ice. In just one day, I began to understand why people want to climb mountains, but it also made me absolutely sure that the unbroken coast-to-coast glacier of the merged Cordilleran and Laurentide ice sheets would have been an absolute barrier to hunter-gatherers at the peak of the last Ice Age.

  From one extreme to another, I also went snorkelling in the chilly coastal waters of British Columbia. Warmly wrapped in 5mm of neoprene wetsuit, I explored the shallow waters around the edges and islands of Sechelt Inlet, north of Vancouver. As well as plenty of sea stars and fish, I saw lots and lots of kelp. And, believe it or not (and at this point it does start to feel as though archaeologists are clutching at straws, or seaweed, or whatever, along the Canadian Pacific coast), kelp has also been implicated in the proposed coastal route into the Americas.

  Kelp forests are incredibly rich ecosystems – among the most productive and diverse habitats on earth. They support a great wealth of marine life: fish and shellfish, marine mammals and birds. For hunter-gatherers on a kelp-forested coast, the marine resources are easily as rich as – if not richer than – those on land, provoking some archaeologists to call the potential coastal route into the Americas the ‘Kelp Highway’. Bears come into the story again here: grizzly bears on the richly provided coast grow two or three times as large as their inland cousins.5 Kelp thrives in cool nearshore waters, preferring temperatures of less than 20 degrees C, and can even survive a winter beneath sea ice. Today, the coastal kelp forests of the north Pacific stretch all the way from Japan to Baja in California. There’s a break along the tropical coasts, where the sea is too warm for kelp, then it starts again along the Andean coast. The kelp forests would have been there, in the rising post-glacial waters, so any prehistoric beachcombers would have been well provided for. Today’s Pacific kelp forests are home to a huge variety of fish, shellfish (such as abalones, sea urchins and mussels), seabirds and sea otters. Before Beringia disappeared beneath the waves, its bays and inlets supported large mammals like walrus and sea cow. Although the sea level around western Canada early in the post-glacial would have been about 100m lower than today, the coastline would have been almost as convoluted and fragmented as it is now. Any coastal hunter-gatherers must have had boats in order to get around and efficiently exploit this environment.5 But as it has been argued that modern humans emerging from Africa – some 60,000 years before the Americas were even glimpsed – were adapted to coastal and estuarine environments and probably had watercraft, it seems quite reasonable to assume the early Americans would have used boats to navigate and forage along the coast.

  Reasonable assumptions are all well and good, but ultimately all this musing about a North American coastal route is, at the moment, conjecture. The genetics may suggest a coastal route, and the conditions may have been suitable (judging from pollen, bears and kelp) for a coastal expansion from 17,000 years ago, but there is no hard evidence for people living along Canadian shores that long ago. The Palaeolithic archaeologists of North America suffer the same problem that plagues those trying to trace ancient migrations just about everywhere else in the world: glaciation has scoured continents and destroyed a wealth of archaeological evidence in its path, and the rising sea levels produced when the ice melted have concealed the Pleistocene coasts. Presumably many of the traces of the first colonisers could be lost beneath the waves. Most of Beringia is now under water, like a Stone Age Atlantis, and the coastline of Alaska and Canada is much higher and further inland than it would have been at the end of the Pleistocene.

  The map shows the ice sheets of North America during the Last Glacial Maximum, stretching from coast to coast, and the retreating ice sheets. The north-west coast became deglaciated about 16,000 years ago, freeing up a potential coastal route into the Americas; the interior ice-free corridor opened 14,000 to 13,500 years ago; the map also shows Bruce Bradley’s suggestion of a North Atlantic route.

  There are some intrepid archaeologists who have explored the submerged Pleistocene coasts of north-west Canada, using sonar to map the sea floor. They found a drowned landscape of ancient rivers, lakes and beaches,6 a landscape that would have been available for humans to inhabit one to two thousand years earlier than the opening of the inland ice-free corridor. This ancient coast was later covered up by a relatively rapid rise in sea level, and this makes the archaeologists very optimistic that any archaeological sites would have been quickly buried under the seabed, and are therefore likely to have been well preserved. Gradual increases in sea level cause much more erosion as they occur,7 and in fact one piece of archaeology has emerged from under the waves: a barnacle-encrusted stone tool was recovered from an ancient river mouth now 53m underwater.

  For the first actual, datable evidence of people on the North American coast, I would have to travel south: to California.

  Finding Arlington Woman: Santa Rosa Island, California

  Just off the coast of Southern California, across the Santa Barbara Channel, lie the Channel Islands. These islands are rich in wildlife and have been home to humans for thousands of years. Historically, the archipelago was settled by Chumash and Tongva Indians, who used purple olivella shells as currency. Spanish explorers, missionaries and ranchers arrived on the islands in the sixteenth century, and nineteenth-century fur traders hunted the native sea otters and seals nearly to extinction. Now the islands and their diverse wildlife are protected, as part of a National Park.

  I flew to Santa Rosa in a six-seater prop plane, late in the day. We took off from Camarillo airstrip and were quickly over the Santa Barbara Channel, heading west. I could just make out the Channel Islands on the horizon. We flew over Anacapa Island, then over the larger island of Santa Cruz, just to the north of its Diablo Peak. The islands were rocky and rugged, with very little sign of human habitation.

  We started descending over the sea, then came into land on a short, dusty airstrip just set back from the shore at Bechers Bay. I was met by rancher Sam Spaulding in his Hilux and we set off on a track that rose steeply into the mountainous interior of the island. Although park wardens and scientists were frequent visitors, there were no permanent residents on Santa Rosa Island. I was staying at the National Park lodges, high up in the hills. I arrived there just as the sun was setting, and I met John Johnson of the Santa Rosa Museum of Natural History, who had come out to the island to be my guide for a trip to Arlington Springs on the other side of the island.

  The following morning we set off early and drove for two hours along rough tracks to the gully known as Arlington Springs. The landscape we passed through was magnificent, sculpted by water. Over the millennia, streams and rivers have gouged deep gullies and canyons in the sandstone, naturally exposing ancient sediments. And in those sediments are fossils of the various long gone inhabitants of Santa Rosa.

  John and I scrambled down the steep banks of the gully to the stream, which meandered its way towards the coast. On the way there were waterfalls and plunge pools that we had to edge around to follow the water down to the sea. In the walls of the gully I could easily make out the layers and layers of sediment that had built up over millennia to then be cut back by the stream. In deep layers, there were fossilised shells: great, clam-like things and ridged bivalves. These were very ancient, from a time when this sediment had been on the bottom of the sea. As we walked downstream, we came across younger sediments, and John pointed out fossil bones sticking out of a reddish bank: a line of crumbly vertebrae and some long bones. Pygmy mammoth bones, no less.

  In 1959, an archaeologist named Phil Orr had been drawn to Santa Rosa Island by its rich Pleistocene fossils. He was trying to create a new track down the side of Arlington Springs gully with a grader, to reach an excavation near the beach. His vehicle became stuck in the gully, and when he got out and looked around he spotted two long bones poking out of the side of the gully, 11m below the top of it. The bones were in the same – Pleistocene – layer as the mammoth bones he was more familiar with. But these weren’t mammoth b
ones. Orr called on the advice of other experts who confirmed what he had suspected: the bones were human. It looked as if he had found the first evidence of ancient humans on the island. The bones were two femora (thigh bones). There was no sign of the rest of the skeleton: the femora were ‘disarticulated’. They appeared to have been washed into the gully and then covered up by later layers of sediments. Orr removed the bones in a block of earth, and, back at the lab, removed fragments to send for radiocarbon dating. In 1960, he published the results: the femora were 10,000 years old.1 Orr thought the bones to be robust and most likely male, and the find became known as ‘Arlington Man’.

  In 1987, John Johnson and his colleague Don Morris had found Orr’s plaster block containing the Arlington Springs bones in the basement of the Santa Rosa Museum, and decided to subject the bones to some modern analyses, including DNA tests and the more reliable AMS radiocarbon dating. Anthropologist Philip Walker looked at the bones and decided that they were most likely to be from a woman: the rough line down the back of the femur where thigh muscles attach was very faint, not robust as it often is in male skeletons, and the slender diameter of the bones also suggested that they were female.1 John showed me reconstructions of the femora, and they were indeed very lightly built. Radiocarbon dating of the human bone itself, and on an associated extinct mouse deer mandible that was buried close by, yielded a date of around 12,900 years ago2 – meaning the skeletal remains of ‘Arlington Woman’ were indeed among the oldest known in North America.

  Although these human remains date to several thousand years after the coastal corridor is thought to have become accessible, they do prove something about the earliest Californians: they must have used boats. At the height of the last Ice Age, the three islands of San Miguel, Santa Cruz and Santa Rosa were joined together, as a single super-island which has been called Santarosae, but it was always separate from the mainland.3, 4