About 1.5 billion pigs yield roughly 120 million tonnes yearly
The domestic pig (Sus domesticus) is an omnivorous even-toed hoofed mammal farmed mainly for pork, with hide used as leather. China leads production, then the EU and United States. Some treat it as a wild-boar subspecies; culture has featured pigs since Neolithic art.
Also known as swine or hog, the species eats both plants and animals and walks on an even number of hoofed toes. Taxonomists disagree about its status. Linnaeus named the wild boar Sus scrofa in 1758, and many treat the pig as its subspecies, Sus scrofa domesticus; in 1777 Johann Erxleben classed it as a separate species, Sus domesticus, a view the American Society of Mammalogists shares. Pigs were domesticated twice in the Neolithic, once in the Near East around the Tigris Basin and once in China. When Near Eastern pigs reached Europe they interbred heavily with wild boar yet kept their domestic traits.
The head is large, and the long snout is reinforced by a prenasal bone and a cartilage disk at its tip, making it both a digging tool and a sharp sense organ. Adults have 44 teeth, the back ones built for crushing, and males' canines can grow into continuously growing tusks that sharpen against each other. Each foot has four hoofed toes; the two central ones carry the weight, the outer pair helping on soft ground. Most breeds are sparsely bristled, though the Mangalitsa has a woolly coat. Adults usually weigh 140 to 300 kg, and one exceptional pig, Big Bill, reached 1,157 kg.
Pigs barely sweat to cool down and pant poorly, so outside their comfort range of 16 to 22 degrees Celsius they wallow in mud or water, which may also guard against sunburn and parasites and help with scent-marking. Their small lungs leave them more prone to fatal bronchitis and pneumonia than other farm animals. Remarkably, pigs share with mongooses, honey badgers and hedgehogs a mutation in the nicotinic acetylcholine receptor that blocks snake venom neurotoxins.
About 1.5 billion pigs are raised each year, yielding roughly 120 million tonnes of meat, much of it cured into bacon, and their hides become leather. China is the largest producer, ahead of the European Union and the United States. Some pigs are kept as pets, and the animal has appeared in art and literature since the Neolithic, with cities such as Bologna celebrated for their pork products.
Source: Pig
