Wolf Tracking Improved: Sound Analysis Reveals Wolves Have Unique Howls

We’ve reported a number of stories of how GPS technology aids wildlife researchers. Specifically, how researchers use GPS tracking collars to monitor wildlife in their natural habitats. We’ve published a few stories specifically about wolf tracking, but none like this. As technology improves, researchers develop new ways to monitor wolf populations.

If you’re reading this blog, then you’re likely familiar with wildlife GPS tracking. Wolves, or other wildlife being studied, are carefully captured, examined and fitted with a GPS collar. From a distance, researchers can study the movements and habits of the wolves this way. Another less popular, but cost effective method is to wait for snowfall and physically count tracks left by wolves. The major downside to this type of wolf tracking is that it is weather dependent.

“Another method researchers use is to go into the wild and howl at the wolves, then record their replies,”  explained Holly Root-Gutteridge from Nottingham Trent University, developer of the sound analysis code. “While this method is definitely the most fun, the results formerly had big error margins, as it was impossible to tell whether you were hearing the same wolf on different nights.”

The sound analysis code is able to individuate wolves based on the pitch and volume of their howl. Wolves howl for a variety of survival and recreational reasons. “Wolves use howling as a territorial defense, to help locate other pack members, and also as a social activity: they seem to really enjoy it,” she added.  

Although most wolf populations are recovering from endangerment, Gray, Red, Maned and Ethiopian wolves are still officially endangered species. “For Ethiopia wolves, which are subject to pressures like rabies and habitat loss, it is critical to keep track of population sizes,” said Lucy Tallents, Ethiopian wolf expert. “The best way of doing this is to count individuals.” 

“Acoustic sensing is becoming much more popular in conservation, and it’s easy to see why,” Tallents explained. “Being able to identify individuals aurally would be really useful to us and cause much less disturbance to the wolves themselves.” One of the reasons acoustic sensing is preferred is that it can be done from a distance and no interference with the animal, like capturing, is required. The major downside is that it’s not very effective in counting individual wolves.  

“We can only ever detect a minimum number of wolves in a pack: if they’re not howling, we won’t know they’re there,” Root-Gutteridge said. “But the real revelation here is that we can now identify individual wolves.” Time will tell how this technology develops and contributes to wildlife conservation efforts. “Although the research hasn’t been released yet, I have successfully used the method on other wolf subspecies and other canids,” she added. “Whether it’s wild dogs or coyotes; if it howls, we can analyze it.”

Wolf Tracking Improved: Sound Analysis Reveals Wolves Have Unique Howls