Pigs, Hogs & Boars: Facts About Swine
Credit: © Martine De Graaf | Dreamstime.com

Pigs are mammals with stocky bodies, flat snouts, small eyes and large ears. They are highly intelligent, social animals, and are found all over the world. 

Pigs are in the Suidae family, which includes eight genera and 16 species. Among those species are wild boars, warthogs and pygmy hogs and domestic pigs. Pig, hog and boar essentially describe the same animal, but there are some distinctions. A boar is an uncastrated male domestic pig, but it also means a wild pig of any gender. A hog often means a domestic pig that weighs more than 120 lbs. (54 kilograms). Pigs are also called swine. 

Pigs were among the first animals to be domesticated, about 6,000 years ago in China. Domestic pigs are descended mainly from the wild boar (Sus scrofa) and the Sulawesi warty pig (Sus celebensis), according to the Encyclopedia of Life. They are classified as a subspecies of wild boars, Sus scrofa domesticus or Sus scrofa scrofa, according to the Integrated Taxonomic Information System (ITIS).

Pigs usually weigh between 300 and 700 lbs. (140 and 300 kilograms). Domestic pigs are often bred to be heavier, according to the San Diego Zoo. A hog named Reggie set a weight record of 1,335 lbs. (605.5 kg) in the Iowa State Fair’s “Biggest Boar” contest in 2012, according to the Des Moines Register. 

This wild boar is a real porker. Although they’re the wild ancestor of domesticated pigs, these guys, <i>Sus scrofa</i>, are much grumpier and can become aggressive if cornered.
This wild boar is a real porker. Although they’re the wild ancestor of domesticated pigs, these guys, Sus scrofa, are much grumpier and can become aggressive if cornered.
Credit: © David Emmett

Wild pigs vary greatly in size and weight. The largest boar is the giant forest hog (Hylochoerus meinertzhageni). It grows up to 6.9 feet (2.1 meters) long, according to the San Diego Zoo. The heaviest boar is the Eurasian wild pig (Sus scrofa), which grows to 710 lbs (320 kg). 

The smallest boar is the pygmy hog (Sus salvanius). It grows to a length between 1.8 and 2.4 feett (55 to 71 centimeters) and 9.8 inches (25 cm) tall from hoof to shoulder. The pygmy hog only weighs 14.5 to 21 lbs (6.6 to 9.7 kg), according to the San Diego Zoo.

Boars, pigs and hogs live all over the world, except for Australia, Antarctica, northern Africa and far northern Eurasia, according to the Encyclopedia of Life. For example, red river hogs (Potamochoerus porcus), also called bush pigs, are found in Africa; babirusas  (Babyrousa babyrussa), or pig deer, are found in Indonesia; and Visayan warty pigs (Sus cebifrons) come from the Philippines. 

Wild pigs typically live in grasslands, wetlands, rain forests, savannas, scrublands and temperate forests. 

Pigs are very intelligent animals. According to the Humane Society, pigs are smarter than 3-year-old children. Domesticated pigs can be trained to do tricks and even use a litter box like a cat. 

They are also very social. In the wild, pigs live in close-knit groups called sounders, according to the San Diego Zoo. Sounders consist of one male, many females and their young. Males without a sounder will form their own herds or be solitary. Bearded pigs can have sounders with up to 300 members.

Pigs communicate with a variety of grunts and squeaks. A short grunt, a longer growl and a loud roar will warn other pigs of approaching danger, according to the San Diego Zoo. The pigs' primary defense is speed, but when cornered, their tusks can be formidable weapons. Their lower tusks can get to be about 3 inches long (7 centimeters) and are razor sharp.

Pigs, boars and hogs are omnivores and will eat just about anything. Wild boars eat roots, fruit, rodents and small reptiles, according to National Geographic. Domestic pigs and hogs are fed feed that is made from corn, wheat, soy or barley. On small farms, pigs are often fed "slop,” which consists of vegetable peels, fruit rinds and other leftover food items. Sometimes, free-range pigs find their own food, according to Oklahoma State University.

A mother pig with piglet.
A mother pig with piglet.
Credit: Agricultural Research Service

Female pigs, called cows or sows, give birth to offspring twice a year to a litter of around 12 young. Baby pigs are called piglets. At birth, piglets weigh around 2.5 lbs. (1.1 kg), according to National Geographic. Within a week, most piglets will double their weight. When they are two to four weeks old, the piglets are weaned. 

Wild pigs can give birth to six for 14 piglets at a time. These piglets will stay in a nest for their first 10 days and are weaned after three months. Wild pigs live five to 20 years.

Here is the taxonomy of pigs according to the Integrated Taxonomic Information System.

Kingdom: Animalia
Subkingdom: Bilateria
Infrakingdom: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Superclass: Tetrapoda
Class: Mammalia
Subclass: Theria
Infraclass: Eutheria
Order: Artiodactyla
Family: Suidae
Subfamily: Suinae
Tribes: Babyrousini, Phacochoerini, Potamochoerini, Suini
Genera: Babyrousa, Phacochoerus, Hylochoerus, Potamochoerus, Sus
Species (in Sus genus):

  • Sus ahoenobarbus (Palawan pig)
  • Sus barbatus (bearded pig), with two subspecies
  • Sus bucculentus (Indochinese warty pig)
  • Sus cebifrons (Visayan warty pig), with two subspecies
  • Sus celebensis (Sulawesi warty pig), with three subspecies
  • Sus oliveri (Oliver’s warty pig)
  • Sus philippensis (Philippine warty pig), with two subspecies
  • Sus salvanius (pygmy hog)
  • Sus scrofa (wild boar, pig, feral pig), with 16 subspecies, including Sus scrofa domesticus (domestic pig)
  • Sus verrucosus (Javan warty pig), with two subspecies

Wild boars are not endangered, according to the International Union for Conservation of Nature’s Red List of Threatened Species. They are listed as "least concern" due to the wild pig's "wide range, abundance, tolerance to habitat disturbance and presence in many protected areas."

Sulawesi warty pigs are listed as “near threatened”; bearded pigs, Palawan bearded pigs and Philippine warty pigs are “vulnerable”; Javan warty pigs are “endangered”; and Visayan warty pigs are “critically endangered.” Hunting and habitat loss are cited as the causes of declining populations in these species.  

  • Domestic pigs have curly tails; wild pigs have straight tails, according to the San Diego Zoo.
  • Eurasian wild pigs attack and eat snakes, according to the San Diego Zoo. The venom doesn't absorb as well because wild pigs have a layer of thick fat. The small amounts of venom that do make it through the fat are easily broken down.
  • Pigs are very useful to the medical industry. Pig hearts are used as replacements for human hearts. Also, insulin and around 40 other medicines are made from pigs, according to Oklahoma State University.

According to OneKind, an animal protection charity based in the United Kingdom.

  • Pigs are very clean and will keep their toilet area far away from where they lie down and eat.
  • Pigs are very peaceful animals, rarely showing aggression, except when a mother with her young offspring is provoked or threatened.
  • Pigs have a tremendous sense of smell. The large round disk of cartilage at the tip of the snout is connected to muscle that gives it extra flexibility and strength for rooting in the ground.
  • Winston Churchill once said, “Dogs look up to man. Cats look down to man. Pigs look us straight in the eye and see an equal.”
  • The pig is the one of the 12 animals in the Chinese zodiac. The pig is seen to represent, fortune, honesty, happiness and virility.

According to Oklahoma State University:

  • Bacon is one of the oldest processed meats in history. The Chinese began salting pork bellies as early as 1500 BC.
  • The Spanish explorer Hernando DeSoto brought the first swine to the New World in 1539.
  • A pig's squeal can range from 110 to 115 decibels. By comparison, noise from a motorcycle reaches about 100 decibels.
  • A pig can run a seven-minute mile.
  • The saying "living high on the hog" started among enlisted men in the U.S. Army, who received shoulder and leg cuts of pork while officers received the top loin cuts. So "living high on the hog" came to mean living well.
  • "A pig in the poke" comes from a common trick in 17th-century England of trying to give away a cat to an unsuspecting "shopper" for a suckling pig (a young pig). When the buyer opened the poke (sack), he "let the cat out of the bag," and the trick was revealed.
  • The phrase "pork barrel" politics" is derived from the pre-Civil War practice of distributing salt pork to the slaves from huge barrels. By the 1870s, congressmen were referring to regularly dipping into the "pork barrel" to obtaining funds for popular projects in their home districts.

Additional resources