Dogs are often cited as man’s best friend, but new research suggests they could have competition — from pigs.
A new study reveals that pigs show just as much affection for their owners as dogs, although dogs are more likely to show you interesting things.
Researchers at Eötvös Loránd University in Hungary discovered that socialized pigs lack the ability to show “referential communication.”
“We suggest that pigs may lack important characteristics that are crucial for the emergence of this type of communication,” said first author Paula Perez-Fraga.
Researchers at Eötvös Loránd University discovered that social pigs won’t try to show us things they find interesting. Pictured: researcher Paula Perez and a pig
The team made this discovery when investigating a pig’s ability to display a “referential connection.” Pictured: Left: Test setup. Right: the experimenter hides food. S = subject, O = owner, B = hiding boxes, E = experimenter, P = plastic container
The team made this discovery when investigating a pig’s ability to display a “referential connection.”
This is an interaction between two parties where one directs the other’s attention to a specific entity.
Humans easily do this using language or gestures, such as pointing at an object, and many animal species have also been found using it with each other, such as dogs.
Chickens can communicate via at least 24 distinct vocalizations, as well as various visual displays, and can be used for referential communication.
When showing roosters computer animations of their predators, they used different alarm calls depending on the type of predator shown.
So when they were shown flying predators, they made one type of alarm call, and when they were shown terrestrial predators, such as raccoons, they made another distinctive alarm call.
For the study, published today in the journal Scientific Reports, the researchers aimed to find out whether this is a necessary trait for the ability, using social dogs and pigs.
What is a “referential connection”?
Referential communication is an interaction between two parties where one directs the other’s attention to a specific entity.
Humans easily do this using language or gestures, such as pointing at an object, and many species of animals have also been found to use them with each other.
Domestic animals, such as dogs, and some social animals such as horses, cats, and kangaroos, have been found to be capable of referential communication with humans.
But, whether animals can communicate referentially with humans is another story.
‘Domestic animals appear to be particularly adapted for referential contact with humans,’ said Ms. Perez-Fraga.
However, some wild, social animals can do this as well, so domestication may not have been key for this communicative ability to emerge after all.
The researchers note that animals that can communicate referentially with humans—whether domestic or not—tend to be species that primarily use visual cues with one another.
For the study, published today in the journal Scientific Reports, the aim was to see if this was a necessary trait for the ability, using social dogs and pigs.
The domestication of dogs is believed to have occurred at least 15,000 years ago, when gray wolves and dogs diverged from the extinct wolf species.
Many researchers believe that their ability to form a bond with humans evolved around the same time they became tamed, likely over thousands of years.
But while pigs have become an increasingly popular pet, they have not undergone the same evolution and are therefore still considered wild.
Dogs are also known to rely heavily on visual communication while pigs are primarily vocal, using grunts and squeals.
All of the participating pigs were raised with human families, so they were familiar with people and their behaviors could be compared to that of dogs
For the experiment, a pig or a dog was led into a room with a food treat under a box. This was inaccessible to the animal but accessible to the owner
She was either left there on her own or with her owner, or she was left with her owner instead but there was no food reward present
All of the participating pigs were raised with human families, so they were familiar with people and their behaviors could be compared to that of dogs.
For the experiment, a pig or a dog was led into a room with a food treat under a box. This was inaccessible to the animal but accessible to the owner.
They were either left there alone or with their owner, or alternatively they were left with their owner but there was no food reward.
“We expected an increase in referential communicative behaviors when both the owner and the food reward were present, implying that the animal was directing the human’s attention to the location of the food,” said lead researcher Dr. Attila Andeks.
For it to be considered a reference behaviour, the animal must first interact with the reward box and orient its body towards it.
Then, they would orient themselves toward their owner if they were present in the room, or the door—which they knew their owner was behind—if they were not.
For it to be considered a reference behaviour, the animal must first interact with the reward box and orient its body towards it. Then, they would orient themselves toward their owner if they were present in the room, or the door—which they knew their owner was behind—if they were not. Pictured: A: time spent heading towards the boxes for dogs and pigs, B: time spent interacting with boxes for dogs and pigs
Although they grew up with humans, pigs made no attempt to direct their owner to therapy. Pictured: A: time spent turning towards the door/owner of dogs and pigs, B: frequency of alternating direction for dogs and pigs
The dogs and pigs were more towards their owner than the door, and alternated between the food box and the owner more than the food box and the door.
This indicates that both species have a similar predisposition to caring for humans.
However, only the dogs alternated between the box and the owner when the box contained more food than when it did not, suggesting that they were trying to direct them to it.
Although they grew up with humans, pigs did not attempt to direct their owners to food, either with visual cues or sounds.
‘We found that when pigs and dogs were alone with their owners, they paid similar attention to them,’ said Dr Andex.
However, after the experimenter hid the treat, the dogs only tried to show their owners where it was.
“The pigs, by contrast, just tried to find a way to take it themselves.”
So the researchers concluded that an animal’s ability to referentially communicate with us may not be the result of human socialization.
Pigs may by nature lack something that is required of them, which may be a preference for eye contact with individuals of the same species.
The authors write: “This, in turn, may be due to anatomical limitations including poor vision and neck stiffness.”
They also claim that the pigs’ strong urge to open the box and reach the food themselves may have outweighed any urge to direct a human toward it.
Scientists translate pigs’ grunts into emotions for the first time
Scientists say they have translated pigs’ grunts into emotions for the first time, in a potential breakthrough for monitoring the animals’ well-being.
The researchers trained an artificial intelligence (AI) algorithm with 7,414 recordings of pig sounds, which were collected throughout the life stages of 411 pigs — including slaughter.
The algorithm could be used to create an app for pig farmers that detects if the animals are happy with just the noise they make.
Experts say that with enough data to train the algorithm, the method could also be used to better understand the emotions of other mammals.
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