Pigs are among the most versatile animals humans have domesticated. Often we think of them as hungry, dirty and not particularly bright, yet anyone who has kept a pig as a pet knows there's a lot more to these creatures. While it's true pigs will eat just about anything, the rest of our perceptions aren't entirely accurate. Here are some surprising, fun 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 by B.C. 1000. The Old Testament, specifically the Book of Leviticus, deemed pigs "unclean" and forbade the consumption of pig productions. The Koran 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. (Photo: 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. Despite its latecomer status in folklore, people born in the year of the pig are considered to be good planners who work hard to achieve goals.

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. However, more research is needed 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. (Photo: chadin0/Shutterstock)

A review of pig studies published in the International Journal of Comparative Psychology suggests that pigs have a complex psychology that we're only now starting 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."

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. That's video of the behavior in the video 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.

As she told National Geographic, it's important because the behaviors of wild pigs like these aren't often studied, and it may have simply gone unnoticed. Plus, it's a trait pigs share with humans. "It brings us closer to animals, and helps us realize it's all connected."

You can learn more about her study, which was published in Mammalian Biology.

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. (Photo: jadimages/Shutterstock)

We use the phrase, "sweating like a pig," but the truth is pigs don't sweat a lot. Sweat is a way that 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 lack of 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.

8 surprising facts about pigs
Pigs are smart, emotional animals that have lived alongside humans for thousands of years. In the Year of the Pig, here are some surprising pig facts.