When people look at pigs, they typically see dirty, sloppy animals. After all, don’t pigs like to wallow in mud? Don’t they eat whatever slop humans put in front of them? Actually, pigs only wallow to keep themselves cool, and many of them are discriminating eaters! Moreover, they make excellent parents, showing care for their piglets long after they’ve reached adulthood. So how many piglets can they have at one time, and how long are pigs pregnant? Find out this and much more below!
Types of Pigs
Both wild and domestic pigs fall under the genus Sus in the Suidae family. They are even-toed, ungulate (hoofed) mammals with four toes on each foot. The scientific name for domesticated pigs is Sus scrofa domesticus. For wild boars, it is Sus scrofa. There are 8 species of pigs with various subspecies and hundreds of breeds.
Pigs are known as highly intelligent, social animals. Their snouts are extremely sensitive, allowing them to forage effectively for food. Domesticated and wild pigs have an obvious difference: the former’s tails are curled, but the latter’s tails are straight.
Pig Appearance and Size
Pigs vary quite a bit in appearance and size, depending on their species and breed. All pigs, regardless of their type, tend to be bulky in the body with short legs and large snouts. They come in several colors ranging from white, pink, gray, brown, and black. Some have spots or patterns. Most pigs have hairy bristles on their backs or snouts.
Most domesticated pigs fall between 300-700 pounds as adults. They stand at about 51-97 centimeters, with a body length of 0.9-1.8 meters. The Guinness Book of World Records lists the largest pig in history as Big Bill, who weighed a massive 2,552 pounds (1.16 t)! He stood 1.52 meters at the shoulder and stretched an impressive 2.74 meters (ca. 9 ft).
Wild pigs can also grow to be significant. The largest is the African giant forest hog, which can grow to be 2 meters long and 1.1 meters tall.
Pig Diet and Predators
As omnivores, pigs can eat almost anything, but not everything is good for them. Farmers feed domesticated pigs foods that give them energy and protein. For energy, pigs eat barley, wheat, and corn. For protein, they consume soybeans and canola meals.
Wild pigs are opportunistic eaters, meaning they will eat whatever is most convenient. Nuts, acorns, grass, roots, bark, truffles, and fungi form part of their diet. They may also eat crops like wheat, corn, rice, oats, potato, watermelon, and cantaloupe. Various insects, reptiles, birds, and small mammals are also acceptable, including eggs.
Pig Social Behaviour
Pigs are highly social animals who form herds called sounders, both for companionship and protection. They also establish hierarchies. Members of the sounder express dominance through aggression and the choice of resting places. Wild pigs live in groups of several females and their offspring. Boars (male pigs) remain on their own except when mating.
Pigs communicate in a variety of ways. Vocally, they grunt and squeak. They also use gestures like head tossing and ear cocking. Pheromones help them communicate by means of smell. Additionally, scientists have observed farm pigs expressing affection by means of “social nosing.” This may take the place of the grooming and licking behaviors found among other species.
Domesticated pigs are found everywhere in the world except Antarctica. Pastures, farmland, and forests are their most common habitats. They thrive in temperate conditions that permit them to spend part of their time outdoors.
Wild pigs are highly adaptable and have managed to carve a niche for themselves in many habitats. These include grasslands, swamplands, temperate forests, rainforests, scrublands, and savannas. They have adapted to so many environments that in some parts of the world, like the United States and Canada, they are considered an invasive species. The only places wild pigs are not found are northern Africa, northern Eurasia, and Antarctica.
Pig Reproduction and Lifespan
Female pigs reach puberty after 6-8 months, after which they are able to breed. Males usually reach puberty by 12 months of age. Domesticated pigs may mate and farrow at any time of year, though it is less likely in summer and early autumn. However, wild pigs generally breed in late winter and farrow in spring when conditions favor their young. Sows (female pigs) farrow (give birth to piglets) in nests.
Most domestic pigs will live between 15-20 years, provided they are not slaughtered. Wild pigs live significantly shorter lives, with the average being between 4-10 years.
How Long Are Pigs Pregnant?
Domesticated pigs are pregnant for an average of 114-116 days. This comes to about 3 months, 3 weeks, and 3 days. Wild pigs may be pregnant for slightly longer, up to 122 days. It is possible for sows to completely absorb a litter for up to the first 35 days of their gestation period.
How Can You Tell If a Pig is Pregnant?
Sows show their first signs of pregnancy around their udders (milk rail). They swell toward the back while the teats drop toward the ground. When the sow is days away from delivery, a gentle squeeze of the teats will produce ready drops of milk. It may take up to 30 days after impregnation to begin noticing a change in a sow’s udder. The vulva will also begin to swell during this time.
The sow will generally get bigger and rounder as the pregnancy progresses. She may slow down and rest more often. Pregnant sows will not go into heat, but boars may still try to mount them. Toward the end, the sow’s appetite will increase dramatically, and she will begin gathering material for a nest.
How Often Can a Pig Get Pregnant?
Sows can give birth to litters up to twice a year. More than this, the litter might not be healthy. However, an unimpregnated female pig can get pregnant every 21 days. This is the length of her fertility cycle after she hits puberty.
Pig Litter Size
Domesticated sows usually bear an average of 7-8 live piglets per litter, though this number occasionally increases to 13-14. Scientists and farmers have increased the average number of piglets per litter by selective breeding. However, this leads to higher rates of stillbirth and other birth complications. It is not uncommon for sows to give birth to more piglets than they have teats.
Wild sows tend to have smaller litters, averaging 4-6 piglets. Again, this number might rise on occasion to as many as 12 piglets per litter.
Pigs may be a staple of our diets and livestock, but they are also complex, intelligent creatures with active social lives. Additionally, they make great parents, protecting their piglets and even “singing” to let them know milk is available.
The photo featured at the top of this post is © iStock.com/kadmy
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