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The Domestic Pig

The many distinctive races of domestic pig are all derived from the wild boar, and are sometimes designated as their own subspecies, Sus scrofa domesticus. The domestic pig is mostly raised as food for humans, and today a population of about 0.85-billion pigs are being raised in agriculture around the world.

Pigs are an ancient domesticate, and they have been cultivated by people for many thousands of years. Today, pigs are raised using various systems of husbandry, which vary enormously in their intensity. The oldest and simplest systems depend on locally free-ranging pigs, which return to their designated domiciles in the village each evening. Whenever they are needed for food or to sell as a cash-crop, individual pigs are killed or taken to the market, while the breeding nucleus is still conserved. Raising pigs in this relatively simple way is common in many subsistence agricultural systems in poorer parts of the world. For example, in the highlands of New Guinea pigs have long been an important agricultural crop, as well as being very prominent in the culture of the indigenous peoples, who measure their wealth in terms of the numbers of pigs owned by a person or village.

Of course, modern industrial agriculture involves much more intensive management of pigs than is practiced in these sorts of subsistence systems. Pigs raised on factory farms may be bred with close attention to carefully designed breeding lineages, often using artificial insemination to control the stud line. Industrial piggeries keep their animals indoors, under quite crowded conditions, while feeding the pigs a carefully monitored diet that is designed to optimize the growth rates. Fecal materials and urine represent a substantial disposal problem on factory farms, which may be resolved by disposal onto fields or into a nearby water body, or if this is prohibited, by building a sewage treatment facility. Pigs grown under these types of rather unsanitary, crowded conditions are susceptible to diseases and infections. Therefore, close attention must be paid to the health of the animals, and regular inoculations and treatments with antibiotics may be required.

The intensively managed husbandry systems by which pigs and other livestock are raised in industrial agriculture are often criticized by environmentalists and ethicists. The environmentalists tend to focus on the ecological damages associated with various agricultural activities, for example, the disposal of sewage and other wastes. The ethicists complain about the morality of forcing intelligent animals such as pigs to live under highly unnatural conditions. The life of an industrial pig includes living under conditions lacking in many sensory stimuli, exercise, and numerous other elements of a happy life, eventually to be crowded into trucks and trains to be transported to a central abattoir, where the animal is slaughtered and processed under generally brutal conditions. The environmental and ethical dimensions of modern animal husbandry are becoming increasingly important considerations in the ongoing debate about the relationships of humans with other species, and to ecosystems more generally. These are important issues in terms of the sustainability of our resource-use systems.

Domestic pigs are sometimes used in southern France to hunt for truffles, which are extremely flavorful and valuable mushrooms that are prized by gourmet cooks. The truffles develop beneath the ground, but they can be easily detected by specially trained pigs, thanks to their relatively high intelligence and extremely sensitive sense of smell.

Sometimes, individuals of the smaller races of pigs are kept as housepets. Pigs are highly social animals, and if raised from a young age they will become highly affectionate and loyal to humans. Pigs are quite intelligent animals, similar in this respect to the domestic dog (Canis familiaris), and this characteristic also enhances their qualities as a pet. In addition, pigs can be rather easily toilet trained. One of the most favored races of pig as pets is the Vietnamese pot-bellied pig.



Grzimek, B., ed. Grzimek's Encyclopedia of Mammals. London: McGraw Hill, 1990.

Nowak, R.M., ed. Walker's Mammals of the World. 5th ed. Baltimore: Johns Hopkins University Press, 1991.

Porter, V. Pigs: A Handbook to the Breeds of the World. Pica Press, 1993.

Wilson, D.E., and D. Reeder. Mammal Species of the World. 2nd ed. Washington, DC, Smithsonian Institution Press, 1993.

Bill Freedman


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—This refers to domesticated animals that have escaped to natural habitats beyond their natural range, and can maintain wild populations, as is the case of many introductions of wild boars.


—The science of propagating and raising domestic animals, especially in agriculture.


—An animal that eats a very wide range of foods, including plant materials, as well as animals. The animal foods may be either predated, or scavenged as carrion.

Additional topics

Science EncyclopediaScience & Philosophy: Philosophy of Mind - Early Ideas to Planck lengthPigs - Species Of Pigs, The Domestic Pig