Tuning in to the Wolf
There are few things that evoke a sense of wilderness more precisely than the primal howl of a wolf. Now, researchers have designed a computer program that can read individual howls well enough to match them up accurately every time with the animal that emitted the long, eerie wail—an achievement that may aid the very conservation efforts that protect wolves and keep them howling in the wild.
The researchers, from Nottingham Trent University in the UK, recently published the findings in the journal, Bioacoustics, which they gathered by recording the vocalizations of Eastern wolves, a branch of canids that now only survives in parts of Canada. Theirs is the first study to achieve such accurate results from recordings taken from the wild, where the rush of wind, water, and other natural noises can make a wolf’s howl difficult to decipher within the acoustic landscape.
“Wolves howl a lot in the wild,” said lead researcher Holly Root-Gutteridge to the BBC. It’s widely known that they do this to protect their territory, and to communicate with their kin. “Now we can be sure...exactly which wolf it is that’s howling,” Root-Gutteridge said. With the new program, the researchers catalogued 67 archived calls made by 10 wolves, and were able to identify the solo howls with 100 percent accuracy. In recordings where wolves howled together in groups, the program identified the source of each howl with a success rate of 97 percent.
The key that has made this new method successful is its ability to measure not only the pitch of a wolf’s howl, which had been done before, but also the volume. “Think of [pitch] as the note the wolf is singing,” Root-Gutteridge said to the BBC. “What we’ve added now is the amplitude—or volume—which is basically how loud it’s singing at different times…It’s a bit like language: if you put the stress in different places you form a different sound.”
But aside from allowing researchers to merely put a face to a sound so to speak, this identification tool also gives conservationists another way of tracking wolves as they move across the landscape. That’s more costly and trickier to do with GPS, so measuring sounds provides an efficient way to tack identities onto the wolves, and to trace those individuals as they move about.
The new technology emerges from a core understanding that wolves don’t all sound the same: “We already knew that wolves, like humans, had distinct voices, and now we are able to identify them with 100 percent accuracy without ever even seeing them,” Root-Gutteridge said, as reported by Wired.
She says that conservationists could soon use the technology to track other creatures that howl, like coyotes. For the North American gray wolf, for instance, currently at the center of a debate over whether or not it should stay on the Endangered Species List, a tracking device like this could help conservationists strengthen the population of just over 6,000 that survive in the North American wilds.
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