By Jaryd Jones ’21
The wolf’s howl is one of the most recognizable sounds in the animal kingdom. However, while we have a basic understanding of why they howl, there is not much research on the specifics of how they use this form of long-distance communication in different situations. Luckily for us curious animal behaviorists, a group of researchers led by Rick McIntyre, the lead biological technician at Yellowstone National Park, was able to study wolf populations in Yellowstone and observe how often howls occur throughout the year. After 10 years of research and over 28,000 hours of observations made in the field, the team was able to conclude that the frequency of wolves howling changed with the seasons as well as other environmental factors. These findings allowed them to better understand what triggers howling and the costs of using such a form of communication.
Before getting into their own research, the team admits that research on this area is lacking. They chalk this up to the fact that unmanipulated observations are hard to come by because social land mammals (wolves, hyenas, lions, etc.) are “somewhat elusive and require large study areas”. Most of what we understand about wolf howling comes from ““evidence that ranges from speculative through anecdotal to quasi-experimental”. Even worse, past research in the area is inconsistent. While some researchers have claimed that howling is at its peak in the breeding season (late winter/February), others argue that the peak is closer to the summer and fall, some even saying as late as October. McIntyre states that the lack of consistency most likely comes from small sample sizes. Most of the data in these studies is based off of wolf populations consisting of 2-3 low density packs over the span of 1-2 years. If there’s anything this study teaches us, it’s that one can never have too much data to work with.
Another piece of info they note is the difference between inter-pack and intra-pack howling. As the name would state, inter-pack howling is the communication that occurs between different wolf packs, or individual wolves of different packs. This howling signals territorial advertisement, defense, and is used to attract mates. On the other hand, intra-pack howling is communication within a pack. This can be used to coordinate movement, rallying the pack to a location for reunion, and general bonding within the group. This difference is important because the two howls are used in different situations, and distinguishing the two gives us a better sense of the level of nuance the wolves are using to communicate.
As for the results of their research, what they found was that in general howling was at its peak frequency from December to February, the pre-breeding and breeding season. This makes sense as wolves howl more during this time in order to bolster their individuality through their howls. Similar behavior activities are seen in other social mammals with one breeding season such as the coyote and the dingo. This finding is also reinforced by the fact that pack cohesion is at its lowest during the breeding season. Howling took a sharp decline going into March and thru May. This is the post breeding season going into when pups are normally born. Because an entire pack will be responsible for a litter of pups, there is less reason for communication within the pack because everyone is already together. Howling increases again in the summer as pups begin to travel with the pack, and frequency increases until it peaks in December, thus restarting the cycle again.
So, with all of this new info in mind, what is the purpose of this newly found knowledge? For McIntyre, it’s all part of the conservation effort to protect wolves from the effects we as humans have on the environment. He writes, “Nonetheless, our results lay a groundwork for comparative studies of howling, particularly in wolf populations where human exploitation may have reduced density and altered social structure, and hence altered the ecological role that howling may play.” In other words, if we can better understand how wolves behave and communicate, we can better understand how human interference has affected them and take countermeasures to prevent more interference.
R. McIntyre, J. B. Theberge, M. T. Theberge, D. W. Smith, Behavioral and ecological implications of seasonal variation in the frequency of daytime howling by Yellowstone wolves, Journal of Mammalogy, Volume 98, Issue 3, 29 May 2017, Pages 827–834,
