How Smart Are Pigs? What Research Says About Pig Intelligence

What experiments show about pig intelligence

Much of the research on pig minds began because pigs are farmed in huge numbers, and scientists wanted to understand what they need for good welfare. In 2015, Lori Marino and Christina Colvin published a review of this research, “Thinking Pigs.” They concluded that pigs share many cognitive abilities with animals usually considered highly intelligent, including dogs, chimpanzees, elephants and dolphins.

Pigs show good long-term memory, learn quickly from rewards, discriminate between objects and symbols, and live in complex social groups where they must track who is who. The sections below look at some of the best-known experiments.

Can pigs use a mirror?

In a 2009 study led by Donald Broom at the University of Cambridge, young pigs were first allowed to explore a pen with a mirror for several hours. Then a food bowl was placed where the pigs could see it only in the mirror. Seven of the eight pigs with mirror experience turned away from the reflection and walked around a barrier to the real bowl, taking on average about 23 seconds. Pigs without mirror experience, by contrast, mostly went to the mirror and looked behind it for the food.

This shows that pigs can learn what a mirror image represents and use it to gather information, a skill few animals have demonstrated. It does not prove that pigs recognize themselves. The classic mirror self-recognition test checks whether an animal notices a mark on its own body that it can see only in a mirror, and pigs have not convincingly passed it.

Can pigs play video games?

In 2021, Candace Croney of Purdue University and Sarah Boysen of Ohio State University reported that four pigs had learned to use a joystick to move a cursor on a computer screen. The pigs moved the joystick with their snouts and had to steer the cursor to a target to earn a food treat. Two were Yorkshire farm pigs, named Hamlet and Omelette, and two were miniature pigs.

All four pigs performed well above chance, although not as accurately as monkeys and apes tested on similar tasks. The researchers pointed out that the joystick had been designed for primates with hands, and that pigs are farsighted and can have trouble focusing on a nearby screen, so the results probably underestimate their ability. It is a striking result: the pigs had to understand that their own action changed something on a screen they were not touching.

Memory and social cunning

Pigs are excellent at remembering locations. In experiments, they learn which of several places has food and return to them selectively, and they can remember where food was hidden after delays. This matches their natural life as foragers that must keep track of good feeding sites.

One of the most famous findings comes from work by Suzanne Held, Michael Mendl and colleagues at the University of Bristol. A subordinate pig was trained to know where food was hidden, then paired with a dominant pig that did not. The dominant pig learned to follow the informed pig and steal its food. In response, the informed pig changed its behavior, for example by holding back or not heading straight to the food when the rival was close. Some researchers see this as tactical behavior similar to that of primates, while others think simpler learning explains it, so the interpretation is still debated.

Pigs also learn from each other. Piglets pick up which foods to eat partly by following their mother, and young pigs can follow a human pointing gesture to find a hidden reward, though less reliably than dogs. Studies in the Netherlands found that pigs react to the emotional state of their pen-mates, becoming more playful or more anxious along with them.

Are pigs smarter than dogs?

Pigs and dogs are often ranked side by side, and on many tasks they perform at a similar level. Pigs may do better on some spatial memory and problem-solving tests, while dogs are much better at reading human signals, such as pointing and eye contact. That difference reflects history: dogs have been bred for thousands of years to cooperate with people, while pigs were bred mainly for meat and fast growth.

The popular claim that pigs are “smarter than a three-year-old child” is not based on a single clear study. Pigs match young children on a few narrow tasks, such as using a mirror to find an object, but children quickly outpace them in language, imitation and understanding other minds.

Why comparing animal intelligence is tricky

Every species is tested with tasks that suit some animals better than others. A test that depends on vision or hands favors primates, while pigs rely heavily on smell and their snout. Motivation matters too: a pig that is not hungry or that is frightened by a new place may fail a test it could otherwise solve.

Scientists therefore prefer to compare specific abilities, such as memory, learning or social skills, rather than give one overall ranking. By that measure, pigs stand out among farm animals and sit comfortably among the clever mammals. For other species often called brainy, see our list of the smartest animals and how smart crows and ravens are.

Myths and facts about pig intelligence

Myth: pigs are dumb, greedy animals. Research shows the opposite: pigs learn quickly, solve problems and have rich social lives.

Fact: pigs have distinct personalities. Studies of young pigs find consistent individual differences in boldness, sociability and curiosity, much like personality traits in other mammals.

Fact: pigs can be trained. Pigs learn tricks, come when called and have long been trained to find truffles by smell in France and Italy.