August 23, 2013
Social Relationships Drive Wolf Howls
Brett Smith for redOrbit.com - Your Universe Online
The howl of a wolf can be one of the most haunting and mysterious sounds of the forest. While scientists aren’t exactly sure why the animals howl, a new study suggests that the reason has something to do with social relationships within a pack.
In a recently published report in the journal Current Biology, a team of European researchers described how when a wolf leaves a pack, its pack-mates will howl based on the quality of their relationship with the departing wolf.
"Our results suggest the social relationship can explain more of the variation we see in howling behavior than the emotional state of the wolf," said co-author 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."
At the Wolf Science Center in Austria, human handlers often take individual wolves out for walks one at a time, always causing the rest of the pack to howl. To understand the phenomenon, the study researchers tracked the wolves' stress hormone levels and collected information on the wolves' social status within the pack and their preferred partners. The team also recorded the actions of individual wolves as one member of the pack was removed.
Observations showed that a wolf will howl more if they have a better relationship with the departing pack-mate and if the departing wolf is of high social rank. The team found no connection between howling and the stress hormone cortisol in saliva samples.
"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.
"Wolves seem to howl more when higher ranking individuals leave because these individuals play quite important roles in the social lives of wolves,” he said. "When they leave it makes sense that the remaining wolves would want to try and re-initiate or regain contact. The same applies for friendship."
Townsend said the team was surprised not to find a connection between physiological stress and howling activity.
"What we expected was higher cortisol levels if the wolves were more stressed when 'friends' leave, but what we found is that cortisol doesn't seem to explain the variation in the howling behavior we see," he said. "Instead it's explained more by social factors - the absence of a high ranking individual or the absence of a closer affiliate."
Understanding wolf behavior has implications for society because the animals live in close proximity to agricultural and residential areas. For farmers who raise livestock, wolves can be a nuisance and need to be kept away at all costs.
This week, news reports in Idaho cited wolves as the cause of the largest mass sheep death in the state’s history. Reports said almost 180 frightened sheep were driven off a cliff and killed just south of Victor, Idaho. Two area gray wolves are the suspected culprits.