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.