A new study suggests that when a member of the wolf pack leaves the group, the howling by those left behind isn't a reflection of stress but of the quality of their relationships.
Researchers based their study on nine wolves from two packs living at Austria's Wolf Science Center.
The findings shed important light on the degree to which animal vocal production can be considered as voluntary, the researchers said.
"Our results suggest the social relationship can explain more of the variation we see in howling behavior than the emotional state of the wolf," Friederike Range of the Messerli Research Institute at the University of Veterinary Medicine Vienna said.
"This suggests that wolves, to a certain extent, may be able to use their vocalizations in a flexible way," he said.
Scientists have known very little about why animals make the sounds that they do. Are they uncontrollable emotional responses? Or do animals have the ability to change those vocalizations based on their own understanding of the social context?
At the Wolf Science Center, human handlers typically take individual wolves out for walks on a leash, one at a time. On those occasions, they knew, the remaining pack mates always howl.
The study is published in the journal Current Biology.