A bleat is good for more than parodying Taylor Swift songs – in goats, it conveys positive and negative emotions that can "probably" be understood by their peers.
This is according to a study published in Frontiers in Zoology led by scientists at Queen Mary University of London, UK, in collaboration with researchers at the University of Roehampton, UK, ETH Zurich, Switzerland, and the University of Turin, Italy.
To find out the extent to which goats can empathize, the researchers investigated the behavioral and physiological reactions of goats in response to calls of other goats relaying positive and negative emotions.
In total, three calls were played (via a loudspeaker) to the listening goats. The first could be positive or negative but the second had to express the opposite emotion to the call that preceded it. The third was selected at random, meaning it could be positive or negative and the same as or opposite to the one that went before.
Various factors – including the emotional state of the caller and receiver, and the type of vocalization (only contact calls were used so the receiver's responses were based only on the encoded emotions) – were controlled for.
The team observed that the listening goat was far more likely to turn to face the source of the sound when the caller's emotion changed. Interestingly, there was also greater variation in the time between the listening goat's heartbeat when a positive call was played and less variation when a negative call was played, demonstrating a physiological change. (It is worth noting: Low heart-rate variability is associated with depression, anxiety, and PTSD in humans.)
"Expressing emotion using vocalizations and being able to detect and share the emotional state of another animal from the same species may facilitate coordination among the individuals in a group and strengthen group cohesion," Elodie Briefer, a co-corresponding author of the paper (then) based at the ETH Zurich, said in a statement.
Goats are highly social creatures but they are not the only (non-human) animals to demonstrate high levels of empathy. Previous studies have shown that odor and visual cues from distressed cattle and pigs can induce feelings of fear and changes in physiology in others of the same species. Meanwhile, domestic dogs and horses appear to exhibit physical and social changes in response to displays of human emotion – as do goats.
"Despite its evolutionary importance, social communication of emotions in non-human animals is still not well understood," said lead author Luigi Baciadonna from Queen Mary University of London.
"Our results suggest that non-human animals are not only attentive, but might also be sensitive to the emotional states of other individuals."
Goat Heidi responding to two positive calls, a negative call, and a randomly selected call. Alan McElligott