• Biodiversity Domestic Pig
  • Domestic Pig

    Sus scrofus domesticus


    Humans have spent centuries living with pigs. Possibly before humans decided to settle down into an agricultural lifestyle, the pig made its home with us. Today, the domesticated version of the wild European boar has hundreds of varieties. Because of this variety, some scientists even considered the domesticated pig to be its own species (Sus domesticus). Yet, we’ll simply take the traditional approach in this treatment, defining the domestic pig as a subspecies of the wild boar: Sus scrofus domesticus.

    In this overview of the domestic pig we’ll highlight some of the more unique and interesting facts about this charismatic barnyard animal. We’ll review some of the most common breeds found on farms across the world. Finally, we’ll show some of the studies that have been done on pig intelligence.

    Pig Terminology

    There are many names for the pig, including swine, hogs, oinkers, and suids. What names are appropriate to call a pig and what aren’t? Here is a quick overview of some of the pig terminology.

    • Piglets : Any suckling pig
    • Gilt: A virgin female pig
    • Shoat: A juvenile male pig
    • Boar: Any male pig that’s not a piglet
    • Barrow: Male pig castrated at an early age
    • Sow: Mature female pig
    • Stag: Male pig castrated at a later age
    • Drift: A herd of domestic pigs
    • Sounder: Not used here, but it’s a group of wild pigs
    • Farrow: A group of piglets

    Domestic Pig Range

    While most wild animals will have a map of the areas they are found, domestic animals rarely have a range map. Instead, we found a map that details where pig production is the highest in the world. In the US there are approximately 60 million pigs in farms at any given time. The other large producers are Europe and China. The following map shows this graphically.

    Pig Intelligence

    Fairy tails and poets give pigs the reputation for being one of the smarter animals on the farm. You may have even heard some people testify that pigs are smarter than dogs. We compiled a list of some of the most recent research about pig intelligence here.

    • Candace Croney (Oregon State) discovered that pigs have the ability to respond to an action with an object. In other words you could say push the ball into the ground. Or pick up the ball. Dogs can’t do that.
    • Suzanne Held (Bristol University) found that pigs are one-trial learners. If they push a lever once and food comes out, they’ve learned it on that single try.
    • Stanley Curts (Univ. Illinois) found that pigs can actually play video games. By using their snouts they were able to move the direction of objects on a computer screen. The ability for an animal to perform one action that distantly effects another action is a pretty advanced cognitive skill.
    • Stanley is also trying to teach pigs a rudimentary language so as to communicate to pigs. He hopes that pigs will be able to tell us when they’re stressed and when they’re happy, etc.
    • Mike Mendel (Bristol Univ) is exploring the ability of pigs to read other pig’s minds. In other words one pig can interpret what a another pig is thinking based on their actions. In his tests he put three pigs in a row. The pig in the middle could see the other two. They then showed food to one pig but not the others. When they opened the gates the middle pig would always follow the pig that had seen the food.
    • Ian Sneddon (Queen’s Univ. Belfast) found that pigs learn better in a stimulated environment. Just like human infants learn better when they’re stimulated as infants and not kept in empty rooms, pigs are the same way. Big surprise?
    • Donald Boom discovered that pigs are self aware when looking at a mirror and can find food by using the mirror’s reflection. Only monkeys, elephants, humans, and a gray parrot have shown the capability to use mirrors.

    Pig Breeds

    According to the Field Guide to Pigs, there are well over 500 breeds of pigs in the world. The following section identifies the most common ones you might find on a farm.

    Yorkshire

    Also called the large white, this white pig, with ears held upright, is the most widely exported pig in the world! Mature adults can reach well over 1,000 pounds. It is known for it’s pork since it has the least amount of back fat of any of the major breeds.

    Chester White

    The chester white is an all white pig with medium floppy ears. It should have no spots on it’s body. Originally, the chester white was developed in the US in Chester country, Pennsylvania. It’s basically a mix of some now extinct breeds.

    Landrace

    This pig is completely white (or slightly pinkish) and exceptionally long. It actually has more ribs than other pigs (17 in total) and is known for its bacon-producing ability. It has lean meat, fast growth, and is very sturdy. The Danes were the first to create this breed, and it has spread throughout the world.

    Gloucestershire Old Spot

    This breed is often known as GOS. This pig has white hair and black spots. Sometimes there is just one spot on either flank, and sometimes there are multiple spots on the pig. The ears are floppy. This breed is almost entirely a bacon breed. Today it is somewhat rare with only about 100 breeders.

    Poland China

    The Poland China is from neither Poland or China. Instead it comes from Warren County in Ohio. A Polish man made the breed popular, though. This pig has white socks, a white snout, and a white tail. The ears usually hang well over the eyes. It has a quiet disposition and a rugged constitution. Males can easily get to 900 pounds. The largest Poland China, however, weighed a whopping 2,552 pounds.

    Large Black

    The large black is used for lean pork. It has large ears that generally cover the face. Its fine hair is black and covers black skin underneath. Because of the increased pigment in the skin, this breed is favored for outdoor rearing. It also has a gentle disposition and produces large litters. Males can reach 700 pounds.

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    Written by Rob Nelson

    Rob is an ecologist from the University of Hawaii. He is also an award winning filmmaker. As principle director of the Untamed Science productions his goal is to create videos and content that are both entertaining and educational. When he's not making science content, he races slalom kayaks and skydives.

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