While they may not exactly be speaking Pig Latin, new research indicates that members of the Suidae family of even-toed ungulates can reveal important information about their personalities and their overall welfare through the grunts they use to communicate.
Published in the latest edition of the journal Royal Society Open Science, the new study was led by researchers at the University of Lincoln and Queens University Belfast, and also found a link between the rate of a pig’s vocalizations and the quality of its living conditions.
As lead author Mary Friel, a PhD student at Queen’s University Belfast, explained Wednesday in a statement, “The aim of this research was to investigate what factors affect vocalizations in pigs so that we can better understand what information they convey.”
“Understanding how the vocalizations of pigs’ relate to their personality will also help animal behaviorists and welfare experts have a clearer picture of the impact those personalities have on communication, and thus its role in the evolution of social behavior and group dynamics in social species,” she added.
Vocalizations can even reveal animal’s overall wellbeing
Friel, Dr. Lisa Collins, a specialist in animal health, behavior and welfare epidemiology in the Lincoln School of Life Sciences, and their colleagues devised a series of experiments involving 72 male and female juvenile pigs which were split between two different types of pens.
Half of the pigs were housed in “enriched” pens with plenty of living space and straw bedding, while the rest were kept in compact, concrete-floored pens (which still met all UK animal welfare requirements, the researchers emphasize). They then conducted both a social isolation test and a novel object test to get a sense of each pig’s personality.
The pigs each spent three minutes in social isolation, then five minutes in a pen with an object it had not encountered before: either a large white bucket or an orange traffic cone. The researchers monitored the behavior and the grunts of the pigs during each test, which they conducted again a couple of weeks later to ensure that the responses of the pigs were repeatable.
Friel, Collins and their colleagues also recorded the frequency of grunts made by counting how many were produced per minute of the test, and studied the impact that the different qualities of environments had on the vocalizations produced. They discovered that pigs which demonstrated more proactive personalities types produced grunts at a higher rate than reactive ones. They also found that male pigs kept in poorer conditions made fewer grunts than those living in better pens, suggesting male pigs are more susceptible to environmental factors.
The research confirms that a pig “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,” Dr. Collins said. “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.”
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