We found that these differences between the Fertile Crescent, New Guinea, and the eastern United States followed straightforwardly from the differing suites of wild plant and animal species available for domestication, not from limitations of the peoples themselves. When more-productive crops arrived from elsewhere (the sweet potato in New Guinea, the Mexican trinity in the eastern United States), local peoples promptly took advantage of them, intensified food production, and increased greatly in population. By extension, I suggest that areas of the globe where food production never developed indigenously at all—California, Australia, the Argentine pampas, western Europe, and so on—may have offered even less in the way of wild plants and animals suitable for domestication than did New Guinea and the eastern United States, where at least a limited food production did arise. Indeed, Mark Blumler’s worldwide survey of locally available large-seeded wild grasses mentioned in this chapter, and the worldwide survey of locally available big mammals to be presented in the next chapter, agree in showing that all those areas of nonexistent or limited indigenous food production were deficient in wild ancestors of domesticable livestock and cereals.
Recall that the rise of food production involved a competition between food production and hunting-gathering. One might therefore wonder whether all these cases of slow or nonexistent rise of food production might instead have been due to an exceptional local richness of resources to be hunted and gathered, rather than to an exceptional availability of species suitable for domestication. In fact, most areas where indigenous food production arose late or not at all offered exceptionally poor rather than rich resources to hunter-gatherers, because most large mammals of Australia and the Americas (but not of Eurasia and Africa) had become extinct toward the end of the Ice Ages. Food production would have faced even less competition from hunting-gathering in these areas than it did in the Fertile Crescent. Hence these local failures or limitations of food production cannot be attributed to competition from bountiful hunting opportunities.
LEST THESE CONCLUSIONS be misinterpreted, we should end this chapter with caveats against exaggerating two points: peoples’ readiness to accept better crops and livestock, and the constraints imposed by locally available wild plants and animals. Neither that readiness nor those constraints are absolute.
We’ve already discussed many examples of local peoples’ adopting more-productive crops domesticated elsewhere. Our broad conclusion is that people can recognize useful plants, would therefore have probably recognized better local ones suitable for domestication if any had existed, and aren’t barred from doing so by cultural conservatism or taboos. But a big qualifier must be added to this sentence: “in the long run and over large areas.” Anyone knowledgeable about human societies can cite innumerable examples of societies that refused crops, livestock, and other innovations that would have been productive.
Naturally, I don’t subscribe to the obvious fallacy that every society promptly adopts every innovation that would be useful for it. The fact is that, over entire continents and other large areas containing hundreds of competing societies, some societies will be more open to innovation, and some will be more resistant. The ones that do adopt new crops, livestock, or technology may thereby be enabled to nourish themselves better and to outbreed, displace, conquer, or kill off societies resisting innovation. That’s an important phenomenon whose manifestations extend far beyond the adoption of new crops, and to which we shall return in Chapter 13.
Our other caveat concerns the limits that locally available wild species set on the rise of food production. I’m not saying that food production could never, in any amount of time, have arisen in all those areas where it actually had not arisen indigenously by modern times. Europeans today who note that Aboriginal Australians entered the modern world as Stone Age hunter-gatherers often assume that the Aborigines would have gone on that way forever.
To appreciate the fallacy, consider a visitor from Outer Space who dropped in on Earth in the year 3000 B.C. The spaceling would have observed no food production in the eastern United States, because food production did not begin there until around 2500 B.C. Had the visitor of 3000 B.C. drawn the conclusion that limitations posed by the wild plants and animals of the eastern United States foreclosed food production there forever, events of the subsequent millennium would have proved the visitor wrong. Even a visitor to the Fertile Crescent in 9500 B.C. rather than in 8500 B.C. could have been misled into supposing the Fertile Crescent permanently unsuitable for food production.
That is, my thesis is not that California, Australia, western Europe, and all the other areas without indigenous food production were devoid of domesticable species and would have continued to be occupied just by hunter-gatherers indefinitely if foreign domesticates or peoples had not arrived. Instead, I note that regions differed greatly in their available pool of domesticable species, that they varied correspondingly in the date when local food production arose, and that food production had not yet arisen independently in some fertile regions as of modern times.
Australia, supposedly the most “backward” continent, illustrates this point well. In southeastern Australia, the well-watered part of the continent most suitable for food production, Aboriginal societies in recent millennia appear to have been evolving on a trajectory that would eventually have led to indigenous food production. They had already built winter villages. They had begun to manage their environment intensively for fish production by building fish traps, nets, and even long canals. Had Europeans not colonized Australia in 1788 and aborted that independent trajectory, Aboriginal Australians might within a few thousand years have become food producers, tending ponds of domesticated fish and growing domesticated Australian yams and small-seeded grasses.
In that light, we can now answer the question implicit in the title of this chapter. I asked whether the reason for the failure of North American Indians to domesticate North American apples lay with the Indians or with the apples.
I’m not thereby implying that apples could never have been domesticated in North America. Recall that apples were historically among the most difficult fruit trees to cultivate and among the last major ones to be domesticated in Eurasia, because their propagation requires the difficult technique of grafting. There is no evidence for large-scale cultivation of apples even in the Fertile Crescent and in Europe until classical Greek times, 8,000 years after the rise of Eurasian food production began. If Native Americans had proceeded at the same rate in inventing or acquiring grafting techniques, they too would eventually have domesticated apples—around the year A.D. 5500, some 8,000 years after the rise of domestication in North America around 2500 B.C.
Thus, the reason for the failure of Native Americans to domesticate North American apples by the time Europeans arrived lay neither with the people nor with the apples. As far as biological prerequisites for apple domestication were concerned, North American Indian farmers were like Eurasian farmers, and North American wild apples were like Eurasian wild apples. Indeed, some of the supermarket apple varieties now being munched by readers of this chapter have been developed recently by crossing Eurasian apples with wild North American apples. Instead, the reason Native Americans did not domesticate apples lay with the entire suite of wild plant and animal species available to Native Americans. That suite’s modest potential for domestication was responsible for the late start of food production in North America.
CHAPTER 9
ZEBRAS, UNHAPPY MARRIAGES, AND THE ANNA KARENINA PRINCIPLE
DOMESTICABLE ANIMALS ARE ALL ALIKE; EVERY UNDOMESTICABLE animal is undomesticable in its own way.
If you think you’ve already read something like that before, you’re right. Just make a few changes, and you have the famous first sentence of Tolstoy’s great novel Anna Karenina: “Happy families are all alike; every unhappy family is unhappy in its own way.” By that sentence, Tolstoy meant that, in order to be happy, a marriage must succeed in many different respects: sexual attraction, agreement about
money, child discipline, religion, in-laws, and other vital issues. Failure in any one of those essential respects can doom a marriage even if it has all the other ingredients needed for happiness.
This principle can be extended to understanding much else about life besides marriage. We tend to seek easy, single-factor explanations of success. For most important things, though, success actually requires avoiding many separate possible causes of failure. The Anna Karenina principle explains a feature of animal domestication that had heavy consequences for human history—namely, that so many seemingly suitable big wild mammal species, such as zebras and peccaries, have never been domesticated and that the successful domesticates were almost exclusively Eurasian. Having in the preceding two chapters discussed why so many wild plant species seemingly suitable for domestication were never domesticated, we shall now tackle the corresponding question for domestic mammals. Our former question about apples or Indians becomes a question of zebras or Africans.
IN CHAPTER 4 we reminded ourselves of the many ways in which big domestic mammals were crucial to those human societies possessing them. Most notably, they provided meat, milk products, fertilizer, land transport, leather, military assault vehicles, plow traction, and wool, as well as germs that killed previously unexposed peoples.
In addition, of course, small domestic mammals and domestic birds and insects have also been useful to humans. Many birds were domesticated for meat, eggs, and feathers: the chicken in China, various duck and goose species in parts of Eurasia, turkeys in Mesoamerica, guinea fowl in Africa, and the Muscovy duck in South America. Wolves were domesticated in Eurasia and North America to become our dogs used as hunting companions, sentinels, pets, and, in some societies, food. Rodents and other small mammals domesticated for food included the rabbit in Europe, the guinea pig in the Andes, a giant rat in West Africa, and possibly a rodent called the hutia on Caribbean islands. Ferrets were domesticated in Europe to hunt rabbits, and cats were domesticated in North Africa and Southwest Asia to hunt rodent pests. Small mammals domesticated as recently as the 19th and 20th centuries include foxes, mink, and chinchillas grown for fur and hamsters kept as pets. Even some insects have been domesticated, notably Eurasia’s honeybee and China’s silkworm moth, kept for honey and silk, respectively.
Many of these small animals thus yielded food, clothing, or warmth. But none of them pulled plows or wagons, none bore riders, none except dogs pulled sleds or became war machines, and none of them have been as important for food as have big domestic mammals. Hence the rest of this chapter will confine itself to the big mammals.
THE IMPORTANCE OF domesticated mammals rests on surprisingly few species of big terrestrial herbivores. (Only terrestrial mammals have been domesticated, for the obvious reason that aquatic mammals were difficult to maintain and breed until the development of modern Sea World facilities.) If one defines “big” as “weighing over 100 pounds,” then only 14 such species were domesticated before the twentieth century (see Table 9.1 for a list). Of those Ancient Fourteen, 9 (the “Minor Nine” of Table 9.1) became important livestock for people in only limited areas of the globe: the Arabian camel, Bactrian camel, llama / alpaca (distinct breeds of the same ancestral species), donkey, reindeer, water buffalo, yak, banteng, and gaur. Only 5 species became widespread and important around the world. Those Major Five of mammal domestication are the cow, sheep, goat, pig, and horse.
This list may at first seem to have glaring omissions. What about the African elephants with which Hannibal’s armies crossed the Alps? What about the Asian elephants still used as work animals in Southeast Asia today? No, I didn’t forget them, and that raises an important distinction. Elephants have been tamed, but never domesticated. Hannibal’s elephants were, and Asian work elephants are, just wild elephants that were captured and tamed; they were not bred in captivity. In contrast, a domesticated animal is defined as an animal selectively bred in captivity and thereby modified from its wild ancestors, for use by humans who control the animal’s breeding and food supply.
That is, domestication involves wild animals’ being transformed into something more useful to humans. Truly domesticated animals differ in various ways from their wild ancestors. These differences result from two processes: human selection of those individual animals more useful to humans than other individuals of the same species, and automatic evolutionary responses of animals to the altered forces of natural selection operating in human environments as compared with wild environments. We already saw in Chapter 7 that all of these statements also apply to plant domestication.
The ways in which domesticated animals have diverged from their wild ancestors include the following. Many species changed in size: cows, pigs, and sheep became smaller under domestication, while guinea pigs became larger. Sheep and alpacas were selected for retention of wool and reduction or loss of hair, while cows have been selected for high milk yields. Several species of domestic animals have smaller brains and less developed sense organs than their wild ancestors, because they no longer need the bigger brains and more developed sense organs on which their ancestors depended to escape from wild predators.
TABLE 9.1 The Ancient Fourteen Species of Big Herbivorous Domestic Mammals
* * *
The Major Five
1. Sheep. Wild ancestor: the Asiatic mouflon sheep of West and Central Asia. Now worldwide.
2. Goat. Wild ancestor: the bezoar goat of West Asia. Now worldwide.
3. Cow, alias ox or cattle. Wild ancestor: the now extinct aurochs, formerly distributed over Eurasia and North Africa. Now worldwide.
4. Pig. Wild ancestor: the wild boar, distributed over Eurasia and North Africa. Now worldwide. Actually an omnivore (regularly eats both animal and plant food), whereas the other 13 of the Ancient Fourteen are more strictly herbivores.
5. Horse. Wild ancestor: now extinct wild horses of southern Russia; a different subspecies of the same species survived in the wild to modern times as Przewalski’s horse of Mongolia. Now worldwide.
* * *
* * *
The Minor Nine
6. Arabian (one-humped) camel. Wild ancestor: now extinct, formerly lived in Arabia and adjacent areas. Still largely restricted to Arabia and northern Africa, though feral in Australia.
7. Bactrian (two-humped) camel: Wild ancestor: now extinct, lived in Central Asia. Still largely confined to Central Asia.
8. Llama and alpaca. These appear to be well-differentiated breeds of the same species, rather than different species. Wild ancestor: the guanaco of the Andes. Still largely confined to the Andes, although some are bred as pack animals in North America.
9. Donkey. Wild ancestor: the African wild ass of North Africa and formerly perhaps the adjacent area of Southwest Asia. Originally confined as a domestic animal to North Africa and western Eurasia, more recently also used elsewhere.
10. Reindeer. Wild ancestor: the reindeer of northern Eurasia. Still largely confined as a domestic animal to that area, though now some are also used in Alaska.
11. Water buffalo. Wild ancestor lives in Southeast Asia. Still used as a domestic animal mainly in that area, though many are also used in Brazil and others have escaped to the wild in Australia and other places.
12. Yak. Wild ancestor: the wild yak of the Himalayas and Tibetan plateau. Still confined as a domestic animal to that area.
13. Bali cattle. Wild ancestor: the banteng (a relative of the aurochs) of Southeast Asia. Still confined as a domestic animal to that area.
14. Mithan. Wild ancestor: the gaur (another relative of the aurochs) of Indian with Burma. Still confined as a domestic animal to that area.
* * *
To appreciate the changes that developed under domestication, just compare wolves, the wild ancestors of domestic dogs, with the many breeds of dogs. Some dogs are much bigger than wolves (Great Danes), while others are much smaller (Pekingese). Some are slimmer and built for racing (greyhounds), while others are short-legged and useless for racing (dachshun
ds). They vary enormously in hair form and color, and some are even hairless. Polynesians and Aztecs developed dog breeds specifically raised for food. Comparing a dachshund with a wolf, you wouldn’t even suspect that the former had been derived from the latter if you didn’t already know it.
THE WILD ANCESTORS of the Ancient Fourteen were spread unevenly over the globe. South America had only one such ancestor, which gave rise to the llama and alpaca. North America, Australia, and sub-Saharan Africa had none at all. The lack of domestic mammals indigenous to sub-Saharan Africa is especially astonishing, since a main reason why tourists visit Africa today is to see its abundant and diverse wild mammals. In contrast, the wild ancestors of 13 of the Ancient Fourteen (including all of the Major Five) were confined to Eurasia. (As elsewhere in this book, my use of the term “Eurasia” includes in several cases North Africa, which biogeographically and in many aspects of human culture is more closely related to Eurasia than to sub-Saharan Africa.)
Of course, not all 13 of these wild ancestral species occurred together throughout Eurasia. No area had all 13, and some of the wild ancestors were quite local, such as the yak, confined in the wild to Tibet and adjacent highland areas. However, many parts of Eurasia did have quite a few of these 13 species living together in the same area: for example, seven of the wild ancestors occurred in Southwest Asia.
This very unequal distribution of wild ancestral species among the continents became an important reason why Eurasians, rather than peoples of other continents, were the ones to end up with guns, germs, and steel. How can we explain the concentration of the Ancient Fourteen in Eurasia?