Short answers, pulled from the story.
A pig, known as Sus domesticus and also called swine or hog, is an omnivorous, domesticated, even-toed, hoofed mammal. Some authorities consider it a subspecies of Sus scrofa, the wild boar, while others, including the American Society of Mammalogists, consider it a distinct species.
Pigs were domesticated independently twice during the Neolithic, in the Near East around the Tigris Basin and in China. The Chinese domestication began some 8,000 years ago, and pigs reached Europe from the Near East at least 8,500 years ago, where they interbred with European wild boar.
Global pork production reached 120 million tonnes in 2023, and China produced more than any other country at 55 million tonnes. The European Union followed with 22.8 million tonnes and the United States with 12.5 million tonnes.
Pigs are relatively intelligent, roughly on par with dogs. They recognise each other as individuals, solve mazes, display self-recognition in a mirror, work with a simple language of symbols, and can be trained to use a joystick with their snout to select a target on a screen.
Adult pigs generally weigh between 140 and 300 kg, though some breeds exceed that range. Exceptionally, a pig called Big Bill weighed 1157 kg and had a shoulder height of 1.5 m, while the smallest breed, the Göttingen minipig, weighs about 26 kg as a full-grown adult.
Pigs wallow because they have few sweat glands, with eccrine glands limited to the snout, so they cannot use thermal sweating to cool down. At higher temperatures they lose heat by wallowing in mud or water through evaporative cooling, which may also protect against sunburn and parasites.
Yes, in 2021 a pig became the first animal to successfully donate an organ to a human body. The procedure used a donor pig genetically engineered to lack Galactose-alpha-1,3-galactose, a carbohydrate the human body considers a threat.