Does it sometimes seem that your porcine patients are communicating with you? In fact, they may be doing just that, a new study suggests.

Researchers at the University of Lincoln in the United Kingdom and Queens University Belfast in Ireland found that grunts made by pigs vary depending on the pig’s personality and can convey important information about their welfare.

The study was published June 29 in the Royal Society journal Open Science.

Seventy-two male and female juvenile pigs were split into two groups. Half were housed in spacious, “enriched” pens with straw bedding, and the other half in compact, “barren” pens with partially slatted concrete floors.

To get a measure of the pigs’ personalities, each pig spent three minutes in social isolation, and five minutes in a pen with a large white bucket or an orange traffic cone they had not previously encountered.

The researchers observed behaviors and vocalizations. They also recorded the frequency of grunts and investigated the effect different quality environments had on the sounds made. 

The same tests were repeated two weeks later to determine if responses were repeatable and the defining characteristic of a personality.

The study indicated that pigs with more proactive personality types produced grunts at a higher rate than the more reactive animals. The study also found that male pigs (but not females) kept in the lower-quality conditions made fewer grunts compared with those housed in the enriched environment, suggesting greater susceptibility among male pigs to environmental factors.

“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,” said Lisa M. Collins, PhD, and one of the study authors.

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