Pigs have learnt to play video games by using a joystick – in a study that underlines their intelligence.
US researchers trained four pigs to control a cursor on a monitor, using their snouts to move the joystick in return for rewards.
They used two micro pigs called Ebony and Ivory, and two Yorkshire pigs, called Hamlet and Omelet, to test the animals’ abilities.
It’s long been known that pigs are more intelligent than dogs, and some have claimed they are the fourth most intelligent creature on Earth.
A series of experiments have shown pigs may learn relatively complex tasks.
Early 20th-century studies found they could solve multiple-choice problems, and later studies showed they could learn to obtain light, produce extra heat for their enclosure and acquire feed.
A 1966 investigation proved the animals can distinguish brightness, colour and space.
Writing in the journal Frontiers in Psychology, Candace Croney of Purdue University, and Sarah Boysen said they showed the animals a video game in which they had to use a joystick to manoeuvre a cursor until it collided with one of four wall-like structures on screen, making a sound, at which point the pig received a food treat.
“Although food rewards associated with the task were likely a motivating factor, the social contact the pigs experienced with their trainer also appeared to be very important,” the researchers wrote.
Even when the equipment failed and there were no treats, the pigs still made correct responses, being rewarded only with “verbal and tactile reinforcement from the experimenter”, they said.
“This may have been due to the strong bond the pigs developed with the experimenter during training.”
Prof Croney said: “Potentially there may be more that pigs are capable of learning and understanding and responding to than we have previously envisaged.”
Philip Lymbery, global chief executive of Compassion in World Farming, said the study highlighted a need for the animals to be treated better. “This latest research shows pigs are even more intelligent than we ever thought, yet we still keep the majority of pigs in the most appallingly deprived conditions on factory farms,” he said.
“These smart creatures are kept in barren, crowded and caged conditions where they are treated like inanimate cogs, like animal machines.
“At the end of their lives, most are then gassed using carbon dioxide, perhaps the cruellest of killing methods. This latest science shows we need a rethink. It is high time we ended the factory farming of pigs and showed them the respect they deserve.”
Rebecca E Nordquist, assistant professor of veterinary medicine at Utrecht University, who was not involved in the study, said the discovery of pig intelligence was relevant because group housing was now the norm in the EU, so pigs need to keep track of social interactions, and farms were increasingly using automated feeders that pigs have to operate themselves.
“Raising farmed species without maternal care, insufficient challenges, and mixing of social groups may all negatively impact cognition. As the body of research grows, we will be able to translate this back to improvement of farms to improve farm animals’ lives,” she wrote on The Conversation.