When cows moo, people should listen.

New research has found that individual cows have unique voices that they use to express an array of emotions in different situations.

Cattle are widely known to be social, herd-dwelling animals. But vocal interactions between cows had only previously been formally studied through the lens of mother and calf relationships, scientists wrote in a study published in Scientific Reports last month. For the new study, researchers wanted to look at how cows communicate with the rest of their herd in different situations.

Diane Kuhl via Getty Images A mother Holstein and her calf.

The research involved a free-range herd of young Holstein-Friesian cows at a farm in New South Wales, Australia. Researchers recorded the cows’ vocalizations in positive contexts ― like times when the cows were in a period of being sexually receptive or were anticipating eating ― and negative contexts, including being denied feed or being isolated from their fellow cows. (The study noted that any negative situations were temporary.) In all, researchers ended up with 333 recordings from 13 cows.

“We found that their voices are individually distinct,” lead researcher Alexandra Green, a PhD student at the University of Sydney, told Atlas Obscura. “But further to that, they’re able to maintain these individual characteristics across the contexts.”

Green didn’t see the findings as necessarily surprising.

“Cows are gregarious, social animals,” she said in a statement put out by the university. “In one sense it isn’t surprising they assert their individual identity throughout their life and not just during mother-calf imprinting. But this is the first time we have been able to analyse voice to have conclusive evidence of this trait.”

She hopes her research ― and helping people understand and pay attention to what individual cows are expressing ― could ultimately improve the lives of cows, particularly in the dairy industry.

“We hope that through gaining knowledge of these vocalisations, farmers will be able to tune into the emotional state of their cattle, improving animal welfare,” Green said.