The Incredible Human Journey (5 page)

That night I slept in my tent at the lodge and was woken up regularly throughout the night by the incredibly loud, explosive noise of Zambezi teak pods popping. And if it wasn’t the teak, it was the sand camwood. And if it wasn’t the camwood, it was all sorts of weird noises that were quite frightening when you didn’t know what they were. But I was in a safari tent with a door, and I was quite secure. So each time I woke up, I snuggled down a little further under my duvet (it was quite chilly) and was soon asleep again.

The following day we set off early, driving 13km away from the village to the nearest waterhole. In the Kalahari there are small rain showers in November and December, and then plenty of rain with summer thunderstorms from January to April. The rest of the year is almost entirely rainless. I was visiting Namibia during the hottest, driest time of the year. Bush fires are common, and in fact there had been one quite close to the village; Arno had driven out to help fight it the night before. The smoke was still rising into the sky behind the ridge. Theo said that Bushmen used to start fires on purpose so that vegetation would send out new shoots and attract the game, and also because it cleared the bush and made it easier to track game. This practice was now banned in Namibia, because of the danger to the people and animals of the Kalahari.

The Kalahari Basin is a huge area, extending across the borders of four countries: South Africa, Angola, Botswana and Namibia. It is ‘semi-desert’: very sandy and dry but still supporting a wealth of plants and animals. What it really lacks is surface water, and, weirdly, this is what seems to have facilitated the survival of the Bushmen and their way of life. In less arid parts, Bantu have moved in to farm the land – and the Bushmen have moved out. But in more arid areas, the Bushmen are well adapted to life in this environment, which seemed so incredibly harsh and unforgiving to me.

Their diet includes the storage organs of plants that have adapted to the dry landscape: bulbs, tubers and roots. And they are expert trackers of the animals that leave their footprints in the sandy soil of the bush. There are no streams in the southern Kalahari: water beneath the ground surface upwells to feed waterholes: some temporary, just there during the wet season, and some permanent, lasting right through the dry season as well. The Bushmen are tied to the waterholes: between these muddy, life-giving pools are vast stretches of uninhabitable desert. And the waterholes are also where the animals go to drink, under cover of darkness. Starting at the waterhole, !Kun and //ao would be able to track antelope that had been drinking there the night before.

Picking up the tracks of an oryx, the hunters set off at a determined pace, an extremely fast walk that occasionally broke into a gentle jog. As they passed raisin bushes, the hunters would grab the small orange fruits to eat. //ao offered me one: it was tough but sweet and tangy. Every now and then I heard a loud clucking noise coming from low down in the bush: the cry of the southern yellow-billed hornbill. We continued, and I tried to follow the spoor as well. Sometimes, the cloven-hoofed prints were obvious on the sandy game trail, but then the oryx would leave the track and head into the bush. We would strike out, through the sparse grass and evil, low-lying thorns, and I couldn’t believe the hunters were still on the trail. But then they’d point out a snapped twig, a crushed leaf, a pile of droppings or another hoof print, and I could see that they were still right on track. This happened again and again. I was amazed at their intuitive ability to track an animal that had passed this way many hours before. At one point, the hunters stopped dead. They had found a large raisin bush –
Grewia flava
– with long, straight branches. !Kun took his axe and chopped down four long branches. This was a precious resource: it was the wood used to make bows and spears. Then we were back on the trail of the oryx.

But not long after – perhaps half an hour – the hunters stopped again. They knelt down and I thought they were inspecting tracks, but instead there was a pile of nuts, like large almonds, on the ground. They were both scooping up handfuls of them, shaking them free of dirt and sand, and putting them into !Kun’s antelope-skin knapsack (a whole skin, sewn together with the legs forming the handles), and I helped them. These were Manketti nuts, much prized by the Ju/’hoansi. (I later cracked one between two stones and it was delicious: a bit like a brazil nut.) The neat pile seemed strange – we were a long way from the Manketti groves. But elephants eat the nuts too, although they can’t digest them: the nuts we’d collected had been left behind after a pile of elephant dung had disintegrated. !Kun and //ao were pragmatic in their approach to hunting. While on the tracks of a potential quarry, they would collect wood, berries and nuts as well.

As they were moving and tracking, the hunters would speak softly to each other. I could still hear the clicks very clearly. The geneticists who investigated the ancestry of the click-speaking people conceded that these languages might have survived for tens of millennia by chance. But perhaps clicks had been retained because they provided a great way of communicating while hunting.
¹
This hypothesis is pretty much impossible to test. All I can say is, having been out with the Bushmen, when they were whispering to each other the clicks were still crystal clear. I don’t think there would be much hilarity generated from a Ju/’hoansi game of Chinese whispers. I can add my own extension of this hypothesis, completely untested (at the time of writing), that clicks, being high-frequency sounds, wouldn’t travel as far as other vocalisations. So a language with clicks might provide a clear means of communication between hunters, moving through the bush close to each other, while being unheard by a more distant quarry.

We had started early in the morning, when the sun was low and the bush was just starting to lose the chill of the night, but the sun soon turned the day from cool to warm to blazing hot. I knew I was sweating, even though I felt quite dry. As soon as sweat appeared on my skin, it evaporated, but I still looked sweatier than the hunters. They were wearing very little, which probably helped in this respect. I had opted for long linen trousers to save my legs from thorns and insect bites, while being cool. As I’d anticipated some running would be in order, I was wearing a sports top and a vest to protect my very white midriff from the harsh sun. I had decided my already tanned shoulders and arms would be safe under a decent layer of high-factor sunscreen. The hunters were wearing very little in comparison: just bead-embroidered loincloths and headbands. But they were also shorter, leaner and much more slightly built than me. Small stature and build makes for a larger surface area to volume ratio: relatively more skin surface for sweat to lose heat from. The idea that Bushmen may be physically adapted to endurance running (or walking) in hot conditions, by virtue of their smallness and consequent ability to lose heat effectively, without sweating much, seemed to be borne out by how much we were all drinking. I could feel dehydration stalking me that morning as we tracked the oryx. I kept up with !Kun and //ao, but I got very hot and drank much more water than they did. While each of the hunters had brought with them just half a litre of water, I had three times as much in my Camelback.

In international sports African athletes dominate distance running. Investigations have shown that there may be a number of reasons for this. Elite African runners have a greater fatigue resistance than non-Africans – able to run for some 20 per cent longer before fatigue sets in. This seems to be due in part to a difference in the composition of the muscles. Body mass is also an important factor: larger and heavier runners, in a hot environment, will not lose heat as quickly as smaller runners, and will reach the point of overheating to exhaustion much quicker. A study run by a group of sports scientists, including Tim Noakes from Cape Town University, showed that, even in cool conditions, larger Caucasian (European) athletes sweated more and had higher heart rates than smaller, African runners. In hot conditions, the Caucasian athletes ran slower than their smaller African colleagues. This is fascinating because it suggests that experienced athletes ‘know’ their limits when it comes to heat exhaustion and adjust their pace accordingly. The African runners ran, on average, 1.5km/h faster than the Caucasians, without overheating.
⁴

I’m certainly not a trained athlete, so this wasn’t a fair comparison, but after three hours of walking and running in the bush I had sweated a lot, and I had drunk all of my water. !Kun and //ao hadn’t even touched theirs. And the tracks had become confused. The oryx tracks were crossed by a kudu being chased by a hyena. The hunters decided it was time to circle back. I was glad they knew the way. With the sun high in the sky, I had lost all sense and means of judging direction. As we made our way back, I saw a truly enormous bird launch itself from a small tree and heavily flap off through the bush: a Kori bustard.

It seems that endurance running was generally important to our early ancestors. While the Bushmen seem optimally adapted to running in the heat, we all have anatomical features in our bodies that suggest we evolved to perform well in endurance running. There are things about the way our bodies are designed that allow us to store energy in tendons and ligaments as we run, providing us with an efficiency gain. You don’t need to be a habitual runner to have these adaptations: they are firmly there, in the blueprint of all our bodies.

Take a look at your feet. They are very strange for the feet of an ape (which, strictly speaking, we are). They’re designed specifically for standing, walking and running on. We have lost the ability to grasp things with our big toe that our close cousins, chimpanzees and gorillas, still possess. Instead, it was more important for our big toe to have been brought into line with the others, to form a stable platform. We also have arches in our feet: a long arch down each side, and an arch across the foot as well. These arches are held in place by ligaments and tendons – which stretch. When you’re running, each time your foot hits the ground these ligaments and tendons act like springs, stretching, and then giving energy back as your foot lifts off. Our Achilles tendons, attaching to the lever of the calcaneum, or heel bone, are massive: another stretchy spring. Humans also have very long legs, which makes for a good, long stride length. And we’ve had long legs for quite a while. The first hominins were australopithecines; they walked around on two legs, but their limb proportions were like those of chimps: long arms and short legs. Early species of
Homo
also had chimpanzee-like limb proportions, but by the time
Homo erectus
came along, at around 1.9 million years ago, long legs had appeared as part of the human package. We also have strong back muscles to stop us pitching forward while we’re running, and very large bottom muscles. Gluteus maximus swings the leg back at the hip joint; it’s hardly used at all during walking, but comes into its own when we run.
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Although the small size of the Bushmen makes them able to lose heat easily, and therefore suits them to running in the heat, all humans have adaptations to heat loss which may also be related to keeping cool during endurance running. We have very little body hair, so we lose heat both by convection and evaporation of sweat. And we have lots and lots of sweat glands.

All these features make us good runners. Compared with other animals – four-legged ones – we are not very fast sprinters at short distances, but we are actually excellent endurance runners. And we are unique among primates in developing this capability of endurance running. Over long distances, trained humans can even outrun horses and dogs.

Some explanations of human anatomy and locomotion have suggested that the apparent adaptations to running are actually just byproducts of a body designed for
walking
on two legs. Certainly, long legs improve efficiency in walking as well as running. But the springiness of the leg and foot, and those big bum muscles, aren’t really used in walking – but they are great for running. American anthropologists Dennis Bramble and Daniel Lieberman gathered the physical evidence and published an article in the journal
Nature
in 2004, arguing that, while walking was undoubtedly a fundamentally important way of getting about, for us and our ancestors the role of running had been overlooked. They suggested that the human body has evolved to cover long distances: walking and running.