How Smart are Pigs?
Are Pigs Smarter Than Dogs and Chimps?
Reading Time: 6 minutes
Are pigs smart? You may have noticed how inquisitive they are, how fast they learn, and how they connect with people. You may wonder just how smart are pigs at dealing with challenges, and if pigs are as clever as dogs. You are not alone! Researchers have posed these questions and can back our observations that pigs are intelligent, curious, friendly, and quick learners. They have found that pigs have some pretty amazing cognitive skills matching those found in dogs and chimpanzees.
How Smart Are Pigs at Foraging in a Natural Environment?
As omnivorous foragers, pigs need sharp and flexible searching skills to find enough food in challenging terrains — an aptitude highly appreciated by those raising pigs on pasture. Hogs have inherited this skill from their ancestor, the wild boar. Pigs have excellent spatial memory, and can remember where they previously found food, how much there was, and how many days ago. They have flexible strategies: avoiding foraged areas, as they would in the wild, or returning to the same location when they realize that feed gets replaced. They can learn to return after a fixed number of days, as at pasture a food resource might regrow. They understand when an object is hidden that it still exists (essential for a digging forager), including when hid in a cup. But if you move the cup, they do not follow it.
Pigs’ sense of smell is as good as dogs’. This amazing sense is used to find good food and communicate with their companions. They hear higher pitched sounds than we can, and are sensitive to the direction the sound is coming from, but they are not as good at picking up quiet sounds. They possess a wide field of vision, although it is not as clear as ours. They see blue and green, but not red. These are all points to consider when we manage pigs. It will help us understand their perspective when handling them and designing housing for pigs.
Their sensitive snouts are pigs’ most important tools for exploring and manipulating their environment. Pigs are exceedingly inquisitive, and require plenty of objects to investigate to engage their inquiring minds. Otherwise, they suffer from boredom and frustration, which can lead to harmful habits. Bear this in mind when designing their enclosures, so you can provide adequate enrichment and toys. Pigs have good memories, so toys need to be changed frequently to prevent boredom. However, they renew their interest in known toys moved to a new location on different flooring, and see this as a new scenario to explore. After a week or so, old toys can be reintroduced and they will appreciate them again.
Can Pigs be Trained?
Pigs learn new procedures very quickly, matching chimpanzees in speed, some even showing greater interest and focus. They quickly learn how to use new feed and water systems, and can even master turning heaters or fans on and off as required. In trials, piglets learned that they needed to press a lever with their hooves for a certain duration. Some found that their hooves kept slipping off, so they used their snouts instead, showing innovative thinking.
Pigs learned to move a cursor on a screen using a modified joystick to get a reward. They even completed the task better than dogs. Some pigs can use mirrors to find the location of food that was only visible in the mirror. While getting used to the mirror, they would move about while watching themselves from different angles. Two pigs learned the meaning of words and gestures for objects (frisbee, ball, dumbbell) and actions (sit, fetch, jump) and understood their different combinations. When all three objects were present, the pigs could perform the commanded action with the requested object (e.g. fetch frisbee).
As you can see, pigs could be easily trained for a reward, as they learn to anticipate an outcome to their actions. They also learn what may follow an event or perception. Think how your pigs might associate sights and sounds with good or bad experiences. Pigs were trained to associate a particular sound with imminent treats, and another with an unpleasant event (isolation or crossing a drop). On hearing each sound, they displayed body language or made squeals that demonstrated their emotions about what was forthcoming. Companions who had not been present to learn what the sounds meant, caught their emotional vibes and performed similar behavior.
How Smart Are Pigs Socially?
Pigs are very social creatures. In the wild, they lived in groups of adult females and their young, while males were solitary or roamed in bachelor herds. Group living requires some give and take, so pigs establish a hierarchy to decide who gets priority access to resources. There will be fighting until the hierarchy is settled. This is why it is difficult to introduce pigs that are strangers. Unfortunately, hierarchy between pigs is not too stable, and fighting can break out. So they need plenty of space to be able to avoid conflict. Divided pens help lower ranking individuals get some peace. In any case, pigs prefer defined areas for different functions — a soft, dry area for sleep, a cool area for toileting, dusty and muddy areas for wallowing, and zones for feeding, foraging, and play.
Social living requires good knowledge of your companions’ identity and rank. Pigs have many ways of identifying other pigs — by sight, sound, and smell — and some can use just one or two senses to pick out a friend. They can differentiate between 30 or more familiar pigs, even when these are closely related, but they cannot identify them in 2D photographs. Sows know the calls of their own piglets. Pigs have individual voices and leave personal signatures in their urine. Voices and urine pheromones also convey other signals, such as emotion and sex. Hogs can tell when a pig is not from their group, and a strange human from a kind, familiar one. They prefer a gentle handler, and do not differentiate between people who treat them roughly. They more willingly approach a strange person once one of their herd-mates has taken the plunge. When identifying humans, they are highly influenced by colors and clothing, but also use body size and facial features of familiar people. However, appearance in a different location may confuse them.
Many pig owners have a caring relationship with their pigs, and share rewarding interaction. Pigs seem to be aware of when they have our attention and are sensitive to our body posture. Pigs can follow pointing gestures when we are down at their level and near to the item we are indicating. They can also follow the direction of our body and face orientation. They use the body orientation of their companions to gauge their perspective — whether or not they can see hidden food. In a foraging study, a subordinate pig was taught where food was hidden, while the dominant was kept unaware. When released together the dominant followed the subordinate and stole her food. Next trial, the subordinate tried different tactics to avoid losing the feed. She only went for it when the dominant was not paying attention and when she had a chance of getting to it first.
Do Pigs Need Play and Enrichment?
Pigs love to play, root, and investigate. This is very important for the health of their lively minds. Housing should incorporate varied opportunities to explore and manipulate objects, as well as frolic with friends. In addition to learning by trial and error, pigs learn from their companions. Piglets learn from their mothers: what to eat, who is safe, and how to forage. In studies, piglets learned from their mother or aunt how to open the door of a box. Pigs preferred to eat the same food as their mothers and familiar companions, but they did not learn from strangers. Sometimes animals are wary of new feed: they do not know whether to trust it. If they see a trusted companion eat it, they are more likely to try it. This behavior can be used to encourage piglets to try new feed. In many cases you, their handler, are a trusted companion, and they may eat anything you give them — so make sure you know how to avoid what not to feed pigs!
Although pigs share many talents with dogs and chimps, it is impossible to say which species is the smartest. Each one has adapted to its own special niche in the environment, with the cognitive skills necessary to succeed in life. All pigs are different in their abilities and personalities. Even this now has scientific backing. We can ensure that their needs are met by taking their perspective on life into consideration.
Marino, L. and Colvin, C.M., 2015. Thinking pigs: a comparative review of cognition, emotion, and personality in Sus domesticus. International Journal of Comparative Psychology. Thinking Pigs: Cognition, Emotion, and Personality http://www.farmsanctuary.org/wp-content/uploads/2016/08/TSP_PIGS_WhitePaper.pdf
Nawroth, C., Langbein, J., Coulon, M., Gabor, V., Oesterwind, S., Benz-Schwarzburg, J., von Borell, E., 2019. Farm animal cognition—linking behavior, welfare and ethics. Frontiers in Veterinary Science 6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6383588/
Nawroth, C., 2017 “Don’t be late for your weekly mud bath!” – Pigs can estimate time intervals in the range of days. https://christiannawroth.wordpress.com
Jensen, P. ed., 2017. The Ethology of Domestic Animals: An Introductory Text. CABI.
Originally published in Countryside in September/October 2019 and regularly vetted for accuracy.