Since Darwin wrote his classic work on The Variation of Animals and Plants under Domestication (1868) a large bibliography has been published on the relationship between humans and animals that is known as domestication. Examples of major publications are Zeuner, F.E. A History of Domesticated Animals (1963); Clutton-Brock, J. (ed.) The Walking Larder: Patterns of Domestication, Pastoralism, and Predation (1989) and Budiansky, S. The Covenant of the Wild: Why Animals Chose Domestication (1992). These and many other works seek to unravel when, how, and why the way of life of the human species became so closely intertwined with other animals. Most of these authors have seen domestication as a process whereby succeeding generations of tamed animals gradually became absorbed into human societies, were increasingly exploited, and eventually lost all contact with their wild ancestral species. Taking a more contentious stance, Budiansky has argued that domestication began as a willing partnership or symbiosis, in which certain species of animals 'chose' to become associated with human societies as a survival strategy at the end of the ice age.

	Thinking Point
	Did some species 'choose' to become domesticated? Is domestication driven by humans alone, or do animals play a part in the process?

It is difficult to define what is a wild and what is a domestic animal. A wild animal is usually thought of as one that is fearful of humans and runs away if it can. But this fear of humans is in itself a behavioural pattern that has been learned from experience of human predation over countless generations. A 'wild' animal that has no contact with humans has no fear of them and is quickly exterminated, like the dodo, or like the fox on the South American island of Chiloe which was killed by Darwin in 1834 and described by him in A Naturalist's Voyage. Journal of Researches into the Natural History and Geology of the Countries visited During the Voyage of the H.M.S. 'Beagle' Round the World. Under the Command of Capt. FitzRoy, R.N. (1845):

A fox (Canis fulvipes) of a kind said to be peculiar to the island, and very rare in it, and which is a new species, was sitting on the rocks. He was so intently absorbed in watching the work of the officers, that I was able, by quietly walking up behind, to knock him on the head with my geological hammer. This fox, more curious or more scientific, but less wise than the generality of his brethren, is now mounted in the museum of the Zoological Society.

In one sense it can be said that a domestic animal is just one which has lost its fear of humans and will breed in captivity, but true domestication involves much more than this. I believe that animals bred under domestication evolve into new species, as a result of reproductive isolation from their wild progenitors combined with natural and artificial selection in association with human societies. The process of domestication is subject to two profound, over-riding and interlocking influences--the biological and the cultural.

The biological process of domestication
The biological process begins when a small number of animals are separated from the wild species and become habituated to humans. If these animals breed they form a founder group, which is changed over successive generations both in response to natural selection under the new regime of the human community and its environment, and by artificial selection for economic, cultural, or aesthetic reasons.

The biological process of domestication can be seen as an evolution that mimics the sequence of events in the differentiation of island races of wild animals from their mainland ancestors. And the main factor in this differentiation is the chance genetic composition of the tiny group of founding animals. Subsequent change has necessarily to be based on the genes and frequencies carried by this colonizing group. The initial founder effect involves a founder event which will be a population bottleneck that results in intermittent and sometimes massive genetic drift. This drift is Iikely to be much more drastic than the more normally assumed persistent drift, where alleles change in frequency relatively slowly. An allele (short for allelomorph) is one of two or more forms of a gene arising by mutation and occupying the same relative position (locus) on homologous chromosomes.

er effect was first introduced into evolutionary theory by Ernst Mayr in 1942 who saw the founder effect as disturbing the genetic cohesion generally assumed to hold species together. With reference to new speciations on islands Mayr wrote that 'the genetic reorganization of peripherally isolated populations does permit evolutionary changes that are many times more rapid than the changes within populations that are part of a continuous system.'

Of necessity, new speciation on islands, as for example with Darwin's finches on the Galápagos islands or his fox on Chiloe, is a single occurrence, whereas the differentiation of domestic species may have had multiple occurrences over the range of the wild progenitor. Thus, there could have been innumerable separate tamings of wolves over this carnivore's vast range which could have led to many small founder populations of domestic dogs, later to be subjected to both natural and artificial selection.

The cultural process of domestication
The second fundamental side to the process of domestication is the equally important cultural process, which affects both the human domesticator and the animal domesticate. Domestication begins with ownership. In order to be domesticated animals have to be incorporated into the social structure of a human community and become objects of ownership, inheritance, purchase, and exchange. As discussed by T. Ingold in 'From Trust to Domination: An Alternative History of Human-Animal Relations' in Animals and Human Societies: Changing Perspectives by A. Manning and J. Serpell (eds.) (1994), the relationship between human and animal is transformed from one of mutual trust in which the environment and its resources are shared to total human control and domination.

This was the basis of the so-called Neolithic revolution when the fundamental change in human societies occurred and groups of hunter-gatherers became farmers and stockbreeders. Many archaeologists have hypothesized that there was a natural progression first from generalized or broad-spectrum hunting in the Palaeolithic, at the end of the last ice age, to specialized hunting and herd following, say, of reindeer or llama. This stage was then followed by control and management of the herds, then to controlled breeding, and finally to artificial selection for favoured characteristics. However, the sequence could not have been so smooth for the social implications of ownership by a social group of hunter-gatherers are a bigger hurdle to domestication than they may seem. Many societies never owned domestic animals, although they did keep dogs. It was probably for cultural, as much as for many other complicated reasons, that the native Americans never domesticated the bighorn sheep, nor the Australian Aborigines the kangaroo.

	Domestication of the dog
	The increase in the world's population of dogs matches that of humankind for there are dogs in every part of the world that is inhabited by people and today there are more than 400 breeds of domestic dog. Each of these breeds owes its existence to artificial selection by humans, because every dog, whether it is a Great Dane or a Chihuahua, is the descendant of wolves that were tamed by human hunters in the prehistoric period. The process of taming probably began at least 15,000 years ago but how much has changed in the actual relationship between human and dog in that period is difficult to assess. It may be that in fact there is very little difference and the relationship is much the same now as it was thousands of years ago. This is because the remarkable kinship and powers of communication that exist between human beings and dogs today have developed as an integral part of the hunting ancestry of ourselves and the wolf. It is a biological link based on social structures and behaviour patterns that are closely similar because they evolved in both species in response to the needs of a hunting team, but which endure today and have become adapdted to life in sophisticated, industrial societies.

The process of taming a wild animal, whether it is a wolf or a wild goat, can be seen as changing its culture. The animal is removed from the environment in which it learns from birth either to hunt or to flee on sight from any potential predator, and it is brought into a protected place where it has to Iearn a whole new set of social relationships as well as new feeding and reproductive strategies.

Although attitudes to the biological divisions between humans and animals are changing, many people will still deny that there can be culture in animal societies. But this is in great part because culture is one of those attributes, like consciousness, that is so hard to understand and to define. In the context of domestication, culture can be defined as a way of life imposed over successive generations on a society of humans or animals by its elders. Where the society includes both humans and animals then the humans act as the elders.

A domestic animal is a cultural artefact of human society but it also has its own culture, which can develop, say in a cow, either as part of the society of nomadic pastoralists or as a unit in a factory farm. Domestic animals live in many of the same diverse cultures as humans and their learned behaviour has to be responsive to a great range of different ways of life. In fact, so closely do many domestic animals fit with human cultures that they seem to have lost all links with their wild progenitors. The more social or gregarious in their natural behavioural patterns are these progenitors, the more versatile will be the domesticates, with the dog being the extreme example of an animal whose culture has become humanized.

Many ethologists will shy away from describing the learned behaviour of animals as culture, and they will use phrases such as the apparently safer 'traditions of behaviour', or describe the animals as 'adaptive decision makers'. I am against this because, after all, what is so special about the cultures of the human species? Whether a baby boy will become, say, an Amazonian hunter or an American philosopher depends entirely on how he is brought up, that is, his culture is the product of learned behaviour passed down through the generations by the elders of his social group.