What Do the Grunts Made by Pigs Really Mean?


Pigs have been known to be quite the companionable pet over the years. In fact, these social animals have been taken into homes and treated similarly as any other household pet, such as dogs or cats, in recent years. And just like any animal, pigs also have their own distinct sound, which is through grunting!

But what exactly do these little piggy grunts mean?

A study by researchers from the University of Lincoln, UK, and Queens University Belfast explored this topic, and found out that these grunts emitted by pigs actually vary and depend on the animal’s personality. They explored the topic of animal behaviour and welfare, and proceeded to conduct an experiment to investigate the relationship between a pig’s rate of grunting and its personality.

The study, which was published in the Royal Society journal Open Science, had 72 male and female juvenile pigs. Half of these subjects were kept in “enriched” pens added with straw bedding, while the other half were situated in more compact “barren” pens with partially slatted concrete floors.

A social isolation test and a novel object test were then conducted to measure the personalities. The researchers had each of the pigs spend 3 minutes in social isolation first, and then 5 minutes in a pen with a large white bucket or orange traffic cone which had not previously encountered. The pigs’ behaviours, vocalizations emitted, and frequency of grunts per minute were recorded. After two weeks, the tests were repeated in order to find out if the pigs’ responses were repeatable. This is known to be the distinguishing characteristic of personality, even in animals.

It was then revealed that the pigs having a more proactive type of personality emitted grunts at a higher rate than the more reactive ones. And, that only the male pigs housed in the lower-quality conditions made fewer grunts compared to the other group housed in an enriched environment.

Indeed, these results add to the evidence that acoustic signalling really does indicate a pig’s personality. According to Dr. Lisa Collins, the principal investigator from the School of Life Sciences at the University of Lincoln, “The domestic pig is a highly social and vocal species which uses acoustic signals in a variety of ways; maintaining contact with other group members while foraging, parent-offspring communication, or to signal if they are distressed.” She adds that, “The sounds they make convey a wide range of information such as the emotional, motivational and physiological state of the animal. For example, squeals are produced when pigs feel fear, and may be either alerting others to their situation or offering assurance. Grunts occur in all contexts, but are typical of foraging to let other members of the group know where they are.”

The lead author from Queen’s University Belfast, Mary Friel, also said that, “Understanding how the vocalizations of pigs’ relate to their personality will also help animal behaviourists and welfare experts have a clearer picture of the impact those personalities have on communication, and thus its role in the evolution of social behaviour and group dynamics in social species.”

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By | 2017-10-16T20:42:22+00:00 July 6th, 2016|Animals and Insects|