We’re always looking for better ways to provide good welfare for animals in our care. But how do we always know environmental enrichments improve the welfare of animals? Sometimes, all you have to do is listen.

Guinea pigs, for instance, have a complex vocal repertoire and at least 11 distinct calls (Berryman, 1976). Contented guinea pigs make a variety of sounds, such as whistling (sometimes referred to as wheeking), which they make when anticipatory or excited, like during feeding. Depending on depth, purrs mean different things, too. A low pitch purr means contentment whereas a high pitch purr signals annoyance. Unhappy guinea pigs also chatter their teeth as a warning. They can make chirping noises as well, a sound pattern similar to a bird song.

As a herd species, guinea pigs live naturally in large family groups. When staff at our Ohio facility went looking to improve the welfare of these animals, they decided to pair house them, instead of keeping them individually housed as they had been. While group housing required some adjustments to data collection techniques, they thought the social advantages of living together would improve the animals’ welfare. It didn’t take long for them to realize it had. Shortly after being paired, the pigs were chirping, tweeting and churring, which are “happy guinea pig” noises that had not previously been heard in the colony. Measuring animal welfare isn’t always easy or straightforward, but sometimes, all you have to do is listen.