The Incredible Human Journey (30 page)

‘Whoever likes the blood can drink it,’ she said. ‘The liver is also good hot, and you can eat the eyes, which are delicious
and good for you. We always eat the raw brains – they’re very tasty and healthy, too.’

Meals with the Evenki consisted of a lot of reindeer meat, mostly boiled, with the water forming a sort of fatty, reindeer
broth. Sometimes there were also bowls of chopped reindeer fat and, once, a bowl of pieces of frozen reindeer milk. I was
lucky in that there was also some bread, small triangles of processed soft cheese in foil wrappers, and bowls of bon bons
(which I suspect were laid on for guests). I had brought some packet meals with me, and the Evenki looked on in mild disgust
as I poured boiling water into these concoctions. One of the children was brave enough to try some – and the other children
ran away from him, screaming.

The meat-rich diet of the Evenki seems somewhat bizarre and unhealthy from a Western perspective, but there’s evidence that
it’s just what the Evenki need in their extreme environment. Our bodies produce heat all the time, as a by-product of metabolism,
and the Evenki have been found to have a very high metabolic rate, probably due to high levels of thyroid hormones. A study
of thyroid hormone levels in the Evenki suggested that there was a correlation with total energy and protein intake. A high
proportion of the Evenki’s energy intake came in the form of protein and fat, not surprising given their reindeer-rich diet.
It seems that eating a lot – in particular, a lot of
meat
– may spur the thyroid gland into producing more hormones. The result: raised metabolic rate and heat production. It’s as
though the body is so well supplied with fuel that it can afford to ‘waste’ some as heat – except that, in northern Siberia,
that ‘wastefulness’ is itself important to survival.
^7
,
8

A diet like the Evenki’s should set the heart disease alarm bells ringing, but, in spite of their meat-rich diet, the Evenki
appear to have paradoxically low levels of ‘bad cholesterol’ in their blood. There are probably a number of reasons for this,
including a genetic predisposition to low cholesterol, a high metabolic rate and a physically active lifestyle, all of which
should help to keep ‘bad cholesterol’ down. Studies of other northern indigenous people have also shown strangely low rates
of heart disease; a high consumption of fish containing omega-3 fatty acids may also play a role. However, very sadly, there
have been recent reports of rising rates of heart disease in Siberian and Alaskan natives, as they move away from traditional
lifestyles. The modern lifestyle diseases of heart disease and diabetes are spreading into the far north.
⁹

That night, Marina and her two children shared the tent with me. There was plenty of room; we slept close to the edges (but
not too close as it would drop to –40 degrees outside during the night), on a raised floor of slim larch logs. The stove
occupied an off-centre position. Marina’s husband was sleeping somewhere else but he would dutifully come in periodically
to check on the stove and replenish the pile of larch logs. We fell asleep in such warmth, with our faces almost roasting in the heat from the stove, that I stripped off most of my layers
inside my down sleeping bag, but left them in the bag in case I needed them later in the night. I did.

We awoke in a cold tent. The temperature inside the tents quickly dropped to match the ambient temperature outside as soon
as the life-giving stove burned out. But before long Marina’s husband had coaxed the stove back to life and I could contemplate
emerging from my sleeping bag and getting layered up, ready to step outside. It felt warmer again, but it was hard to tell
if this was a real change in external conditions or if I was acclimatising to my new environment. Certainly, I was now out
and about in –20 degrees, thinking how pleasantly mild it was, very different from my initial reaction to the same temperature
when I had stepped off the plane in Yakutsk. But the Evenki were walking around in far fewer layers than their recently acquired
and rather less self-sufficient companion. Many of the snowmobile drivers on the journey to the camp had kept their heads
covered with reindeer hoods but their faces had been bare the entire way.

Cold adaptation in humans is a tricky subject. It’s very difficult to be sure if what you’re looking at in terms of anatomy
is an adaptation to, rather than a consequence of, an environment. Short stature and limbs certainly make sense in a cold
climate as this reduces the surface area to volume ratio, making it easier to keep body warmth in. But short stature may also
be the result of cold stress as the body is growing, in other words, a by-product of cold rather than an adaptation to it.
Short limbs, though, may be a true anatomical-physiological adaptation to low environmental temperatures: something which
is
inherited
rather than acquired as a child grows.

In the 1960s the anthropologist Carlton Coon and others proposed that facial characteristics such as narrowed eyes, epicanthic
folds, small noses and broad, flat faces – i.e. East Asian, or what were then described as ‘Mongoloid’ features – were specific cold adaptations, protecting the eyes and creating fewer projecting ‘corners’ to get cold. But at the other end of the landmass,
large
noses are put forward as cold adaptations in Neanderthals and modern Europeans, designed to warm icy air before it’s drawn
into the lungs. And if East Asian features are cold adaptations, why haven’t northern Europeans ended up looking the same?
The theory starts to look decidedly shaky.

It seems unlikely to me that the environment could have been such a powerful sculptor of our bodies and faces when a fundamental
characteristic of modern humans is the use of culture to buffer ourselves from such pressures. Being able to sew fur together
to create protection from the elements would have been essential for the initial colonisation of northern Siberia, as it clearly
still was for day-to-day survival in this extreme environment. Looking at the poor little girl who had ridden in on a sledge
the same night as me, with an enormous chilblain blister on her right cheek, it was also clear that the Evenki were not immune
from the cold. And, beyond intuition and anecdote, various researchers have presented anatomical and physiological evidence
to show that East Asian faces cannot be the result of cold adaptation. Steegman published a series of papers along these lines
in the sixties and seventies, including a report of a physiological study where he had compared the surface temperature of
the face in Japanese and European people, at zero degrees, and found absolutely no difference in the thermal responses;
¹⁰
indeed, he wrote, ‘If anything, the thin and hawk-like visage of the European is better protected from cold than that of
the Asiatic.’ Evolutionary biologist Brian Shea
¹¹
looked at the facial anatomy of Eskimos; he suggested that the internal architecture of
the nose and sinuses might show some evidence of cold adaptation, but concluded that there was nothing to support the general
idea of Asian faces being ‘cold-engineered’.

Having eliminated cold adaptation, we are still left with the question of why (or indeed where and when) typically East Asian
features arose. I will return to these questions later in this chapter, with the fossil and genetic evidence that I explored in China.

Staying with cold adaptation for a minute, though, there does seem to be some interesting recent research suggesting that
there
may
be some adaptive changes in northern populations – not in faces, but deep inside cells. There are very few examples of definite Darwinian or genetic adaptations among modern humans. Sickle cell anaemia and Stephen Oppenheimer’s thalassaemia in South-East
Asian populations are rare examples, and the links in the chain are understood: the gene(s) responsible, the effect on phenotype
(the observable characteristics: in these examples, the effect on blood), and the way in which a mutation confers its selective
advantage (protection against malaria infection in these cases).

The boosting of thyroid hormones and metabolic rate discussed earlier is a short-term, physiological mechanism that allows
the body to effectively turn excess food into heat, not an example of a Darwinian adaptation to cold. The proposed genetic
adaptation to the cold is related to the efficiency of mitochondria. In these minute ‘power stations’, of which there are
thousands per cell, dietary calories are transformed into a package of energy that can be used by the cell (adenosine triphosphate,
or ATP). Mitochondrial DNA contains the genes coding for just thirteen proteins, all of which are employed in energy production.
Doug Wallace of the University of California, aficionado of all things mitochondrial, has studied how genetic mutations in
mtDNA could alter the efficiency of mitochondria. A less efficient system produces less ATP per calorie, and loses energy
as heat. So here comes the adaptation: Wallace argues that, in the tropics, mitochondria tend to be very efficient and generate
little heat, whereas, in the Arctic, mutations make the mitochondria less efficient, and they produce heat.
¹²

So while I was relying on chemical reactions inside bags of hand-warmer granules to keep my fingers going, it seems that the
Evenki may have been benefiting from their own internal heat generation. And the short-term physiological response stimulated
by the Evenki’s meaty diet would have further amplified that effect: thyroid hormones mainly work on mitochondria. Native
Siberians have higher metabolic rates than non-natives on a similar diet. Even if I’d eschewed my vegetarianism and eaten
reindeer meat, I still wouldn’t have been able to compete in the production of metabolic warmth.

It does seem that modern humans are the only hominins to have colonised the Arctic and subarctic regions of the far north.
This feat of survival may have depended on a whole range of adaptations, biological, behavioural and cultural, which together
made it possible for humans to flourish in Siberia, and heat-generating mitochondria may be among those adaptations. But one
other adaptation seems even more important: it was reindeer hunting, providing a meat-rich diet and fur for cold-weather clothing, that paved the way for colonisation
of the north.

Back to the Evenki, and the camp was getting busy as the brigade prepared to move house. It was remarkable how quickly a chum
could be taken apart and packed up ready to be moved off on reindeer-drawn sledges. Once the stove had been dismantled and
taken away, it was time to start on the tent itself. I helped to untie the leather strips holding the reindeer-hide covering
on to the larch skeleton of the chum. Tricky little knots involved removing my gloves to work with bare fingers for a few
minutes each time before the cold got to my fingertips and I had to plunge them back into my mitts to recover. Nevertheless,
the hides came off quickly and we then folded them up and tied them on to sledges. Then the tepee-like framework of larch poles was taken apart. All the poles were simply resting together, apart from the final
three, which were tied at the top to create a tripod, which gave the chum its strength. These were toppled and separated, and then all that was left was the floor of larch branches. It was interesting to reflect
that there would be no archaeological trace of this temporary dwelling.

The twenty-foot larch poles were tied up and attached to the back of sledges, and we were ready to set off: a caravan of reindeer
sledges moving through a snowy landscape. The female leaders of the herd had been lassoed and came with us on the caravan,
and as I looked back along the snowy valley my eyes met an extraordinary sight. The
entire
herd
was following us, surging like a great wave through the woods. You could hardly separate individuals: it was like a flood
of fur, hooves and antlers, flowing down the valley behind us. And this, of course, was the whole point of the nomadic lifestyle
of the Evenki: their reindeer needed to migrate, to move on to fresh pastures, however strange it may have seemed to think
of the lichen buried beneath the snow as ‘pasture’. But as soon as we stopped the herd was busy digging down through the snow
with hooves to get at their food. Piers said it was difficult to work out who was leading whom. The reindeer herd periodically
felt the urge to migrate; their human companions needed to anticipate this and direct their movement accordingly

At a new
site we dug out a circle of snow with wooden spades, and the air was full of the smell of freshly cut larch as small trees
were brought over and stripped of their branches to create a floor for the chum. The three foundation poles went up first,
and then more poles laid up against them, about twenty in all. Then we unfolded the hides and tied them in place. Reindeer
skins were spread on the larch branches inside. Just ten minutes later, we had something that looked like home.

But having nomadised with the Evenki, it was time to continue my own migration. The temperature was dropping by the day and
Vasily advised us to travel out that afternoon, so Piers, Anatoly and I packed up and readied ourselves for the snowmobile
caravan again. This time, in daylight, it was much warmer than the trip out (this was relative by now: it was still less than –20 degrees), and I even risked going without goggles. Riding, facing backwards, on the sledge, I waved to the Evenki children as we left the camp, and had one last view of the
reindeer herd among the trees, and then we were off into the woods and snow. The landscape was beautiful: we rode for a long
time in a valley alongside pink cliffs, and I saw rolling snow-clad hills stretching off into the distance. Eventually, the
windows of Olenek came into view, shining out in the distance like a cluster of beacons, reflecting the orange light of the
setting sun.