Lesser Beasts: A Snout-to-Tail History of the Humble Pig (3 page)

TWO

Out of the Wild

I
n 1989 archeologists discovered a tiny ancient village in the foothills of the Taurus Mountains and began digging with haste: the Turkish government was building a dam on the nearby Batman River, a tributary of the Tigris, and the area would soon be inundated. The site, known as Hallan Cemi, dated to about 11,000 years ago. Most of the buildings the archaeologists excavated were tiny round huts of wattle and daub, just six feet in diameter, though there was one larger ceremonial building with a cattle skull mounted on the wall. Among the debris were beautifully carved sandstone bowls, decorated grinding stones, and obsidian tools.

The villagers of Hallan Cemi had formed a complex society with a rich cultural life, but they were hunter-gatherers, not farmers. They ate wild lentils, bitter vetch, almonds, plums, and
pistachios. They hunted sheep, goats, deer, and pigs. The first three were unquestionably wild animals. The site’s pig bones, however, told a more complicated story.

Nearly half the pigs eaten at Hallan Cemi were killed at less than a year old, a profile very different from the broad age range found in hunted animals. The bones also were overwhelmingly male, suggesting that the villagers had spared females to serve as breeding stock. During the time that Hallan Cemi was occupied, moreover, deer bones became less common while pig bones increased in number. Both deer and wild pigs are forest-dwelling creatures, so if the pig bones at Hallan Cemi came from wild animals, their numbers should have declined along with those of the deer.
The fact that they did not makes it likely that the destruction of forests killed off the deer, while pigs found a new habitat, living alongside humans in the village.

The changes at Hallan Cemi form one small part of the most significant event in human history: the invention of agriculture. This era, known as the Neolithic or New Stone Age, arose independently, and at very roughly the same time—10,000 to 5,000 years ago—in Asia, the Near East, the Americas, and Africa. Given how widespread it was, the rise of farming was likely triggered by a single phenomenon: the end of the ice ages and the warming of the climate. But many mysteries remain. Why would anyone choose the rigors of agriculture over the comparatively easy life of hunting and gathering? Why did prehistoric humans domesticate some animals and plants but not others? And how did the process of domestication take place?

Hallan Cemi lets us begin to answer some of those questions, at least with regard to pigs. The archaeological record suggests that
Sus scrofa
took up life in villages because, as omnivores, they were biologically equipped to eat the garbage generated by newly sedentary humans. Most hunter-gatherers, after
all, moved on to a fresh campsite before the stench grew too foul. In the first permanent settlements, pigs acted as sanitation service and food source, transforming butchery waste, rancid almonds, and moldy wheat into meat. Pigs proved useful to people—but that doesn’t mean the relationship developed solely because of human intention.

It’s commonly held that humans domesticated pigs, but that’s not quite right. Wild boars, in adapting to the new niche created by human settlements, evolved in ways that made them capable of living in close proximity to people. Pigs, in other words, domesticated themselves.

A
natomically modern humans,
Homo sapiens
, arose about 250,000 years ago in Africa. Between 60,000 and 130,000 years ago—there is much disagreement on timing—they crossed the Red Sea, entered the Arabian Peninsula, and from there spread all over the world. That means the Eurasian wild boar and modern humans first crossed paths in the Near East, that confluence of continents in the eastern Mediterranean.

The eastern Mediterranean is generally an arid land, but coastal marshes and the riverbanks provided habitat for pigs. The amount of good habitat available varied considerably, because over the last 2 million years the Earth’s climate has shifted from warm and wet to cold and dry every 100,000 years or so. About 20,000 years ago—some 9,000 years before people settled at Hallan Cemi—the Earth was in the grip of the last great ice age. Rivers dried up, and ice locked up so much of the Earth’s water that the coast of the Mediterranean Sea was five or ten miles from its current location. Steppes covered with grass and scrubby brush dominated the landscape, and forests survived only in the uplands. Humans in the region, like those
everywhere else in the world, lived as hunter-gatherers. They collected wild grains, beans, and nuts and used stone-pointed arrows and spears to kill game.

The wild boar emerged in Southeast Asia about 4 million years ago and then colonized nearly every corner of Eurasia, from mountain to desert to jungle. When the first groups of
Homo sapiens
ventured out of Africa into the Near East some 60,000 years ago,
Sus scrofa
was already there waiting for them.

When the weather warmed about 15,000 years ago, the people of the Near East found themselves living in a world where food was abundant. They gathered nuts and fruit from forests of oak, pistachio, almond, and pear trees and harvested grains and legumes from huge stands of wheat, barley, rye,
lentils, and peas. Hunting became easier because animal populations exploded in the warmer, wetter landscape.

With nature so bountiful, there was no need to travel far in search of food. People built permanent dwellings in villages like Hallan Cemi. They used stone sickles to harvest wild grains and stored them in bins for the dry season. For grinding wild grains they invented stone mills, a heavy appliance that hunter-gatherers would have refused to lug to their next campsite. Technology thus reinforced the cultural transformation that initially began as a response to the changing environment.

This village way of life spread throughout the region. The expansion was a simple matter of demographics: hunter-gatherers needed to carry not only their belongings but also their youngest children from camp to camp, which meant that they spaced offspring—perhaps through infanticide—at intervals of three or four years. Freed from this limitation, the population of settled villages exploded.

The good times lasted a couple of thousand years. Then another cold spell arrived about 10,800
bc
. Populations had boomed in warm weather, but now the wild sources of food that had sustained them disappeared.

Faced with hunger, people realized that they didn’t have to wait for wild cereals to grow on their own: they could take the seeds they had gathered and stick them in the ground. The earliest known domesticated plant, rye, dates from 10,000
bc
, in the midst of this cold snap. The newly arid climate also shrank the size of lakes and rivers, exposing thousands of acres of rich soils ready for planting.
The people became farmers.

Those of us on the far side of this shift might ask what took them so long. Anyone who’s spent time farming—let alone farming with stone tools—knows the answer: gathering food from the wild is far preferable to growing it. Farming is hard
work. It also tends to lead to social stratification, famine, and epidemic disease.
That’s why one scholar has labeled agriculture “the worst mistake in the history of the human race.” But the people of 10,000
bc
couldn’t have predicted this. For them, farming was a matter of survival. When nature stopped providing, they provided for themselves.

The cold spell ended about 9600
bc
, and the global climate warmed again, entering a period of stability known as the holocene (which is now ending, some scientists propose, as we enter the anthropocene, an era of climate change caused by human activity). Once again, wild food flourished. People could have returned to the foraging ways of their ancestors, but they did not. Instead, they got more serious about farming. In the Near East, the period from 10,000 to 6000
bc
witnessed the domestication of wheat, barley, lentils, and chickpeas, as well as pigs, goats, sheep, and cattle. Wheat remains one of the world’s staple grains (along with corn from the New World and rice from Asia), and the region’s domestic animals have become the primary sources of meat and dairy products all over the world.

The success of farming in the Near East owed much to the weather. The climate was hot and dry in the summer, cool and rainy in the winter. Cereals and legumes grew in the winter and lay dormant in the soil during the hot, dry summer. That required large seeds, with a tough shell protecting a kernel of carbohydrates that served as the seed’s energy source. Those carbohydrates became food for the humans who harvested the seeds.

Large grains were useful enough when collected from the wild, but once people started planting them, another change occurred. Wheat and other grains had evolved a seed head that shattered when ripe, scattering seeds to the ground. If the head didn’t shatter—which could happen as the result of a simple
genetic mutation—the seeds remained high above the ground, unable to germinate, directed down an evolutionary dead end. But then humans came along. On a few occasions, they would have come across a stand of wild cereal after it had ripened, and the plants with this mutation would have made up a disproportionate percentage of the harvest. People would have kept these seeds to replant, thereby perpetuating the mutations. This reversed the course of evolution: an undesirable quality in nature became indispensable to human culture. Soon humans selected for other desirable qualities in the plants, such as increased seed sizes and thinner seed coats. Thanks to these first experiments in plant breeding, people enjoyed more bountiful crops that were easier to harvest, thresh, mill, and eat.

M
utated wheat and barley was waiting for humans, ready to be plucked and planted, but animals were different. People could kill and eat them, but they couldn’t take wild beasts back to the village and commence a captive breeding program. Domesticating animals entailed a more complex process.

Throughout history people have tamed all sorts of wild animals—kangaroos, monkeys, cassowaries, cheetahs, moose, giraffes, and brown bears—apparently for the simple pleasure of keeping pets. But when those individual animals die, their tameness dies with them. Domestication, by contrast, is an evolutionary process in which a species adapts to living alongside humans. Whereas taming involves individual animals, domestication involves populations. Pet keeping might be thought of as an initial evaluation to see if the animal might work out as a permanent employee: many animals were interviewed, but few were hired.

Those animals that made the cut—large domestic beasts like cows, pig, sheep, goats, horses, camels, and llamas—have
certain things in common. They eat widely available foods such as grasses and leaves (unlike, for instance, koalas, which require specific types of eucalyptus leaves). They reproduce fairly quickly (unlike elephants, which gestate for almost two years). They respond to threats by bunching up rather than by scattering (as white-tailed deer do). They aren’t too aggressive (like African buffalo) or agile (like fence-leaping gazelles).
Perhaps most importantly, they live in groups structured by a dominance hierarchy, a trait that allows humans to step in at the top position and assert control of the herd.

This pattern helps explain why certain animals became domestic while others didn’t. But it doesn’t allow us to peer back into history to see precisely how these animals first made the transition from a wild to a domestic state. In order to understand that, we must look at individual cases of domestication.

The domestic goat, which likely emerged from the shifting hunting tactics of humans, offers a relatively clear-cut case. All of the goat breeds that exist today are descended from the wild Bezoar goat, which lives in high mountains stretching from Turkey into Pakistan. Archaeologists in the region have uncovered ancient heaps of goat bones in caves occupied by humans during a period stretching from 45,000 years ago to about 9,000 years ago. For nearly all of that period, most of the bones came from adult animals, both males and females. Then, starting about 9,000 years ago, the bones of subadult males begin to predominate.
After that time, very few male goats lived to adulthood. By contrast, almost all of the females did.

In the earlier periods, it seems, the hunters focused on immediate returns, killing adults because those animals had the most meat on their bones. The later pattern—killing males at younger ages while allowing females to grow older—reflected what we might call a sustainable harvesting strategy, intended
to ensure that animals would be available for hunting in the long term. The shift most likely reflected dwindling resources. At this time, roughly 12,000 years ago, the people living in the mountains from present-day Turkey to Pakistan underwent the same climate-induced stresses as those at lower altitudes. The weather warmed, and human population boomed, increasing the hunting pressure on local animal populations; this, combined with a cooling climate, caused the herds of wild goats to dwindle. The hunters changed their hunting strategies to meet the new conditions. They killed young males—only a few were needed for breeding—and protected females, who gave birth to kids and thereby sustained the herd’s population.