Seasoned safari-goers are no doubt familiar with a lion’s roar. Those deep bellows can be heard from miles away – the sound is emblematic of the African bush. A leopard’s roar, on the other hand, is one that most of us probably don’t hear quite as often.
Leopards have what is described as a “sawing” roar; an undulating grumble that does sound remarkably like a handsaw being thrust through a piece of wood. It’s also unique to each cat. So much so that in a recent study published by the Zoological Society of London, scientists say it is possible to identify individual leopards by their personal roars.
The study – a bioacoustics survey of large African carnivores – was among the first of its kind. Bioacoustics is the scientific study of animal sounds in nature, and lead author and University of Exeter PhD student Jonathan Growcott sifted through approximately 75,000 hours of audio and camera trap footage recorded over 62 days in Tanzania’s Nyerere National Park. His research team captured a total of 217 roars from seven leopards, though Growcott was able to spare himself painstaking minute-by-minute data analysis through audio-visual comparison.
“Because we deployed bioacoustics and cameras in the exact same locations, we were able to see that when a lion or leopard walked past the camera, we had concurrent audio,” he says.
It didn’t take long to realise that leopards were often vocalising as they walked within sight of the cameras. By parsing temporal patterns in the audio files containing these roars, researchers were able to determine unique sound characteristics and identify individual leopards with 93% accuracy. That vocalisations can vary from one animal to the next may not seem like a groundbreaking revelation, but the study is evidence that bioacoustics can serve as another valuable instrument in the conservation toolbox – especially for elusive species.
“Audio has been used in marine studies and with birds and primates as well, but with large carnivores? It’s just really hard,” explains Growcott. “Leopards are solitary. They’re nocturnal. They’re vulnerable to extinction. They exist over massive amounts of territory that spans well beyond the protected areas – a leopard’s home range can go up to 800 square kilometres. Getting data on these animals is really hard to start with, and the fact that bioacoustics is still quite an emerging field in lots of senses, being able to put out microphones and reliably get this data just wasn’t done.”
Conservation work often relies on what can be seen, but as anyone who has heard roars, yips or growls in the night can attest, just because we can’t see something doesn’t mean it isn’t there. Bioacoustics could help researchers determine leopard population densities, as well as better understand how and why the oft-lone cats communicate.
“The possibilities of bioacoustics are endless, I think,” says Growcott. “Discovering that leopards have unique roars is important scientifically, but it’s kind of a basic finding. It just shows how little we know about leopards and large carnivores generally.”
Global markers – like International Leopard Day on 3 May – help bring awareness to the plight of endangered species, but there’s no better way to connect than to see these incredible creatures for yourself. Learn more about where to see leopards right here on the Expert Africa website.
