The findings shed important light on the degree to which animal vocal production can be considered as voluntary, researchers said. (Agencies)
"Our results suggest the social relationship can explain more of the variation we see in howling behaviour than the emotional state of the wolf," said Friederike Range of the Messerli Research Institute at the University of Veterinary Medicine Vienna.
"This suggests that wolves, to a certain extent, may be able to use their vocalizations in a flexible way," said Range.
Scientists have known very little about why animals make the sounds that they do. 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.
Range and her colleagues measured the wolves' stress hormone levels. They also collected information on the wolves' dominance status in the pack and their preferred partners. As they took individual wolves out for long walks, they recorded the reactions of each of their pack mates.
Those observations show that wolves howl more when a wolf they have a better relationship with leaves the group and when that individual is of high social rank. The amount of howling did not correspond to higher levels of the stress hormone cortisol.
"Our data suggest that howling is not a simple stress response to being separated from close associates but instead may be used more flexibly to maintain contact and perhaps to aid in reuniting with allies," Range said.
The findings shed important light on the degree to which animal vocal production can be considered as voluntary, researchers said.