It is thought that
the earliest were the people called Scythians, between the rivers
Volga and Irtysh. Horses had already been used for centuries (by
the Hittites, for instance) to draw chariots, but the great new
step was to saddle and train them for fast riding. This new
technique, and the nomadic way of life, spread all over Central
Asia in the course of the first millennium b.c. Meanwhile, in the
deserts of Arabia, other herders had learned to ride camels. In
about 1100 b.c., as we read in the Book of Judges, the hosts of
Midian descended on Israel, camel-mounted; and early in the first
millennium a.d. camel nomadism began to spread into North
Africa.
The most striking
difference between nomad and hydraulic societies was in numbers.
The area of China within the Great Wall has been calculated as
1,532,795 square miles. The combined area of Outer Mongolia (now an
independent state) and Inner Mongolia (now part of China),
dominated until recently by the pastoral way of life, has been
calculated as 914,100 square miles, or about three fifths the area
of China. Yet the population of the two Mongolias in the 1930s, not
counting recent farmer migrants from China, has been estimated as
roughly 2,000,000, while that of China itself was estimated at the
same time as roughly 450,000,000. So the number of Chinese per
square mile was about 150 times the number of Mongols. The
difference had persisted throughout history.
The life of the
nomads was based entirely on their herds, which provided meat, milk
produce, and hides and fleeces for clothing, harness, and even the
tents that served them as homes. To support the large herds, they
grazed them for a time on one area, and then moved to another. Just
as the forest farmers were always moving on to fresh woods, steppe
nomads were always in search of pastures new. They needed even more
land than the forest farmers, and their populations were even less
dense. On the steppe, as in the forest, numbers had to be kept low
if the system was to work.
A moderate amount of
grazing is often good for the grasses and clovers that are most
nutritious and palatable for stock. Periodic removal of their
leaves stimulates them to grow again, more vigorously than before.
Grazing animals have preferred them for millennia, so they are now
best fitted to respond to the stimulus. Under moderate grazing,
they often spread at the expense of less nutritious plants. If the
number of stock on a given area is just right, the good grass on
any given part of it is stimulated and also periodically rested.
But if this stocking rate rises too high, the whole area will be
continuously grazed, and good grasses will have no chance to rest
and grow lush. They will begin to die out, and be replaced by the
less nutritious plants they formerly crowded out. The land will be
overgrazed.
The effects of
overgrazing have been observed in recent years in many countries of
the dry belt (such as Iraq, Israel, and the Yemen), but they have
been most thoroughly studied in the dry western states of the
U.S.A., where much overgrazing went on in the 19th and early 20th
centuries a.d. The sequence of events can be illustrated by studies
of ranges in southern Idaho. If grassland is grazed at a moderate
rate, it is plentifully covered with nutritious perennial grasses
that go on growing year after year. With heavier grazing, the
perennials are killed off, and replaced by tougher but less
nutritious annual grasses that die every year and grow again from
seeds. If the grazing pressure increases further, the annuals are
killed before they can set seed, and are replaced by unpalatable
shrubs, notably the sage-brushes called Artemisia, growing
in scattered clumps over otherwise bare, dry, easily eroded
desert.
As less-nutritious
plants take over, the animals need a larger area to get the same
amount of nourishment. In Idaho, when perennials cover 50 per cent
of a site, one cow can be supported on 3 acres; when they cover 25
per cent, she needs 5 acres; when they cover only 5 per
cent, she needs 15 acres; and when the land turns to desert, no
cattle can be raised there at all. So overgrazing is a vicious
cycle. Too many animals overgraze the land till it supports fewer
than it did to begin with, so the overgrazing gets worse; as more
land turns to desert, the rest is grazed more heavily than
ever.
As long as nomads
and their herds were few enough over a given area, they could graze
each part of it just the right amount before going on to the next.
But the balance was more precarious for them than for forest
farmers because of the effects of drought. Drought has effects
rather like those of overgrazing. A few good years, and herds began
to increase. A few bad years, and the effects of overgrazing were
added to the effects of drought: the combination was
deadly.
The distribution of
springs for watering the animals was another critical factor. On
the Moghan steppe in northwestern Iran, where transhumant herders
today bring their flocks down from the hills in winter, areas
around springs and streams are always overgrazed. As long as there
was plenty of room, the nomads could solve their problems by
migrating long distances at times of crisis. But the nomads became
so specialized for moving over long distances that they lost many
opportunities for insurance against bad years. Their migratory way
of life discouraged staying in one spot long enough to raise a food
crop for themselves or a fodder crop like hay that could be stored
for difficult periods, or even to dig a well. They became more and
more dependent on natural supplies of water and grass.
The hair-trigger
balance was easily tipped. Stock was the only wealth of the nomads.
(It is the main status symbol in many dry parts of Africa today.)
So there was a constant temptation to increase the numbers of stock
beyond safe limits. We have seen what happened to the forest
farmers when they increased their numbers or tried to produce a
large surplus. When the numbers of the nomads or their herds rose
too far, the result could be more dramatic: events on the steppe
always moved fast.
A survey in 1962 of
the Karamoja district of Uganda casts some light on what must have
happened when stock became too numerous. Because of modern
veterinary control of cattle diseases in Karamoja, the population
of cattle in this district had risen steeply during the last few
years. According to the report: "As pasture deteriorates from
overgrazing, tribes begin to jostle. . . . With population growth,
inter-sectional conflict has increased, because groups, deprived of
their traditional grazings, move elsewhere to survive." As a
result, there had been serious deterioration of law and
order.
Karamoja is a
limited district, where a civilized modern government frowns on
range wars. In the vast open steppe, with no such restriction,
disputes over pasture and water took a different course. Tribes,
jostled by neighbours, jostled others in turn, in a chain reaction
spreading across continents. If other conditions favoured it
(especially conditions on the borders of the hydraulic states), the
result could be a forcible gathering of tribes into great empires,
exactly as happened between hydraulic states disputing water
rights. But the empires of the steppe formed a great deal faster.
The conquered did not have to be reorganized and integrated into an
alien bureaucracy. They just joined the horde. So a small group
could grow by combining all its neighbours into one great army,
through a snowball process in which each conquered group swelled
the conquerors' numbers
The rulers of these
hordes allotted pastures, migration routes, and watering rights to
their subjects. But they also had to be expert generals. The horde
needed unified command, and nomad emperors were even more absolute
than the hydraulic kings. Just as those kings found themselves
equipped with mass labour, which they turned to any use they could,
so the steppe emperors found themselves at the head of formidable
armies, spoiling for action and eager to invade the lands of the
farmers, and convert as much as possible to pasture. They descended
on the hydraulic societies like locusts, with equally destructive
results. There was nothing stable about the restless hordes, and
they could build nothing permanent. They subsided again into
fragments when the force of their explosion was spent. But the
explosion itself happened again and again. Outside the great inert
hydraulic empires, the nomads were always poised like a time-bomb,
waiting to go off next time they fused into a horde. This fusion
reaction supplied the final ingredient of human history in the dry
belt.
Despite their far
smaller total population, the nomads attacked the teeming millions
of civilization with devastating effect. Their terrific
mobility enabled them to concentrate hundreds of thousands of men
at a single point, where they suddenly appeared in overwhelming
force. To terrified peasants and city folk, they seemed innumerable
swarms, like the Midianites, who "came up with their cattle and
their tents, and they came as grasshoppers for multitude; for both
they and their camels were without number: and they entered into
the land to destroy it."
While some herders
moved in on civilized societies and became meat-eating rulers
otherwise utterly remote from their ancestors, others began to
develop a new kind of society in the open steppe or desert.
Transhumance had prepared them for a wandering life, and in due
course they took the next logical step, and became true nomads,
migrating over much greater distances in search of water and grass.
Instead of just commuting between summer and winter pastures, they
now roamed over whole continents. Cut off from any close contact
with civilization, other than a mixture of trading and raiding,
these wild nomads of the steppe evolved a mode of life different in
many ways from that of the hydraulic societies.
The transition to
full nomadism was made possible by taming and harnessing fast
riding animals, the horse and the camel. Between 1000 and 900 b.c.,
horse-riding nomads began to appear on the steppes of Central Asia;
it is
