8 Surprising Facts About Pigs

Pigs are smart, emotional animals that have lived with us for millennia.

piglet walking through grass and dandelion flowers
Pigs are more than just cute snouts and curly tails.

Danielle D. Hughson/Getty Images

Pigs are among the most versatile animals humans have domesticated. While they're often stereotyped as gluttonous, dirty, and not particularly bright, anyone familiar with actual pigs knows they're incredibly intelligent and complex creatures. Here are some fun, surprising facts about pigs.

1. Humans Domesticated Pigs at 2 Different Times, in 2 Different Places

We recognized pigs' usefulness early on. Two different cultures thousands of miles apart domesticated wild pigs, or boars. Near what is now modern-day Turkey, settlers domesticated wild boars that came to their villages for scraps of food about 10,000 years ago. Research also indicates that around 8,000 years ago, wild pigs were domesticated in China's Mekong Valley.

2. Pigs Developed a Dirty Reputation

Despite their domestication and usefulness, pigs fell out of favor to a certain degree around 3,000 years ago. The Old Testament of the Bible, specifically the Book of Leviticus, deemed pigs "unclean" and forbade the consumption of pig productions. The Quran followed suit in the 7th century. While theories abound as to why pigs were held in low esteem, the likeliest reason is that pigs are happy to consume just about anything, including decaying food and even feces.

3. The Pig Holds a Place in the Chinese Zodiac

An illustration in red and gold to illustrate the 2019 year of the pig
People born in the Chinese zodiac's year of the pig are believed to be intelligent and creative types. momo design/Shutterstock

The pig is the 12th symbol in the 12-year cycle of the Chinese zodiac. It earned last place in the mythological race to determine each animal's place in the zodiac. The pig, having gotten hungry and then sleepy during the race, was the last to arrive at a meeting called by the Jade Emperor, according to folklore.

4. Pigs Can Save Human Lives

If you ever need a new heart valve, a pig may come to the rescue. Pigs' heart valves are used to make valves for humans. According to Harvard Health Publishing, these valves last around 15 years and typically don't require the use of anti-clotting drugs as mechanical valves do.

What's more, pigs are generally considered the best option for xenotransplantation, or organ transplants between humans and animals. They're just similar enough to us that their organs may work well in our bodies while still being different enough that a cross-species infection isn't as likely as it would be with other primates. More research is needed, however, as trials have resulted in the rejection of some transplants.

5. Pig Are Intelligent, Emotional Creatures

Pigs gather near a gap in the slats of their pens
Pigs have demonstrated that they care about one another's well-being. chadin0/Shutterstock

A review of pig studies published in the International Journal of Comparative Psychology suggests pigs have a complex psychology that we're only now beginning to understand. "Pigs display consistent behavioral and emotional characteristics that have been described variously as personality. e.g., coping styles, response types, temperament, and behavioral tendencies," the authors wrote.

The review also found that pigs respond to each other's emotions. "Emotional contagion in pigs involve[s] responses to other pigs' anticipation of positive or negative events, revealing the importance of social factors in emotion." Cognitive tests have shown them to be smarter than dogs.

6. They Even Use Tools

Ecologist Meredith Root-Bernstein was studying some special pigs in France when she noticed a behavior that had never been noted before. Visayan warty pigs were using sticks and bark scraps to build nests. (You can see video of the behavior in the clip above.) These specific pigs are endangered, which is why she was studying them in a zoo environment, but the unprompted behavior counts, according to Root-Bertstein. The nest building doesn't happen all the time, only every six months or so when the pigs are expecting the arrival of piglets.

7. Pigs Don't Really Sweat

A pig stands in a mud puddle, dripping mud
Since they can't sweat very well, pigs need other ways to cool off. jadimages/Shutterstock

We use the phrase, "sweating like a pig," but the truth is pigs don't sweat a lot. Sweat is a way warm-blooded animals keep cool, but they need functional sweat glands to do that. Pigs have the glands, but they don't work well. This is why pigs will roll around in mud to keep cool.

8. Pigs Have Crummy Vision but a Great Sense of Smell

Pigs can see things along the sides of their head—useful for spotting food, other pigs, and potential predators—but they're not great at seeing what's right in front of them. They make up for this poor frontal vision with an excellent sniffer. They can use their snouts to detect food, and thanks to a little extra muscle that gives it flexibility, the snout also can root out food.

9. Pigs Communicate With Each Other

Piglets learn to recognize their mother's voice and answer her call. She in turn will "sing" to her babies while nursing them. Pigs are said to have more than 20 distinct grunts and squeals that all mean different things, from expressing hunger to seeking a mate.

10. Pigs Have an Excellent Internal Compass

Pigs are surprisingly good at navigation and have been known to find their way home over long distances. They can trot quickly when they need to, hitting speeds of up to 11 miles per hour. Research suggests that boars and warthogs may be able to detect north and south using a built-in magnetic compass, similar to homing pigeons and salmon, and researchers suspect that domesticated pigs likely have the same sense.

Why This Matters to Treehugger

At Treehugger, we are advocates of animal welfare, including our pets and other domestic animals. The better we understand our fellow creatures, the better we can support and protect their wellbeing.