It may come as no surprise to dog owners that our pooches try to show us things they find interesting, like a treat or a toy.
But while notable similarities have been found between the two species, a pig probably won’t lead you to its favorite slime any time soon.
Because researchers at Eötvös Loránd University in Hungary have found that pigs socialized by humans do not share this behavior with dogs.
“We suspect that pigs may lack important traits critical for the emergence of this type of communication,” said first author Paula Pérez Fraga.
Researchers at Eötvös Loránd University have found that human-socialized pigs don’t try to show us things they find interesting. Pictured: researcher Paula Perez and a pig
The team made this discovery while studying the pig’s ability to demonstrate “referential communication.” Image: Left: Structure of the test. Right: Experimenter hides the food. S = subject, O = owner, B = stash boxes, E = experimenter, P = plastic container
The team made this discovery while studying the pig’s ability to demonstrate “referential communication.”
This is an interaction between two parties where one draws the other’s attention to a specific entity.
Humans do this easily with speech or gestures, such as pointing at something, and many animal species have also been found to use it with one another, such as dogs.
Chickens can communicate using at least 24 different vocalizations as well as various visual displays and use them for referential communication.
When roosters are shown computer animations of their predators, they use different alarm calls depending on the type of predator shown.
So when they were shown flying predators they gave off one type of alarm call, and when they were shown terrestrial predators like raccoons they gave off another distinctive alarm call.
For the study published today in Scientific Reports, the researchers wanted to determine if this is a necessary trait for the ability to use dogs and socialized pigs
WHAT IS “REFERENTIAL COMMUNICATION”?
Referential communication is an interaction between two parties in which one directs the other’s attention to a specific entity.
Humans do this easily with speech or gestures, such as pointing at something, and many animal species have also been found to use it with one another.
Pets such as dogs and some human-socialized animals such as horses, cats, and kangaroos have been found to be capable of referential communication with humans.
But whether animals can referentially communicate with humans is another story.
Ms. Pérez Fraga said: “Pets seem to be particularly well suited to referential communication with humans.
“However, some wild animals socialized by humans can do this as well, so domestication may not be key to the emergence of this communicative ability.”
The researchers found that animals that can referentially communicate with humans — domestically or not — tend to belong to species that primarily use visual cues with each other.
For the study, published today in Scientific Reports, they wanted to find out if this is a necessary trait for the ability to use dogs and socialized pigs.
Dog domestication is believed to have occurred at least 15,000 years ago when gray wolves and dogs diverged from an extinct wolf species.
Many researchers believe their ability to bond with humans evolved around the same time they became more tame, likely over thousands of years.
But although pigs are becoming an increasingly popular pet, they haven’t gone through the same evolution and are therefore still considered wild.
It is also known that dogs rely heavily on visual communication, while pigs are primarily vocal, using grunts and squeaks.
All participating pigs had been raised in human families, so they were familiar with humans and their behavior could be compared to that of dogs
For the experiment, a pig or a dog was led into a room with a food reward under a crate. This was inaccessible for the animal, but accessible for the owner
They were either left in there alone or with their owner, or alternatively they were left with their owner but no food reward was provided
All participating pigs had been raised in human families, so they were familiar with humans and their behavior could be compared to that of dogs.
For the experiment, a pig or a dog was led into a room with a food reward under a crate. This was inaccessible for the animal, but accessible for the owner.
They were either left in there alone or with their owner, or alternatively they were left with their owner but no food reward was provided.
dr Attila Andics, the principal investigator, said: “We expected an increase in referential communication behavior when both the owner and the food reward were present, implying that the animal drew the human’s attention to the feeding site.”
In order to be counted as referential behavior, the animal would first have to interact with the reward box and align its body with it.
Next, they would orient themselves by their owner if they were present in the room, or by the door – which they knew their owner was behind – if they weren’t.
In order to be counted as referential behavior, the animal would first have to interact with the reward box and align its body with it. Next, they would orient themselves by their owner if they were present in the room, or by the door – which they knew their owner was behind – if they weren’t. Image: A: time spent orienting on the dog and pig pens, B: time spent interacting with the dog and pig pens
Despite being raised with humans, the pigs didn’t try to draw their owner to the treat. Pictured: A: Time spent orienting toward the door/owner for dogs and pigs, B: Frequency of orientation change for dogs and pigs
Dogs and pigs orientate themselves more towards their owner than towards the door and switch between feeder and holder more than between feeder and door.
This shows that both species have a similar willingness to care for humans.
However, only dogs switched between box and owner more often when the box contained food than when it did not, suggesting that they were trying to steer them there.
Although raised with humans, the pigs made no attempt to lure their owner toward the treat, either through visual or vocal cues.
dr Andics said: “We found that pigs and dogs, when alone with their owners, paid him/her similar attention.
“However, after the experimenter hid the reward, only dogs tried to show their owners where it was.
“Pigs, on the other hand, were just trying to find the way to take it themselves.”
The researchers therefore conclude that an animal’s ability to referentially communicate with us may not be the result of human socialization.
Pigs may inherently lack something required for what could be a penchant for visual communication with members of the same species.
The authors wrote, “This, in turn, can be caused by anatomical limitations such as poor vision and neck stiffness.”
They also claim that the pigs’ strong desire to open the box and access the treat themselves may have overridden any desire to direct a human to it.
Scientists translate pig grunts into emotions for the first time
Scientists say they’ve translated pig grunts into emotion for the first time, marking a potential breakthrough for animal welfare monitoring.
Researchers trained an artificial intelligence (AI) algorithm on 7,414 recordings of pig sounds collected during life stages, including slaughter, from 411 pigs.
The algorithm could potentially be used to build an app for pig farmers that would tell if the animals are happy just by the noise they make.
With enough data to train the algorithm, the method could also be used to better understand the emotions of other mammals, experts say.
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