Take a second to think about how visual our daily lives have become. How much do we rely on our sight to perceive what is around us? All too often, natural sounds pass us by because we are always too plugged in to allow them in. Inevitably, we miss out on a great deal that we simply cannot see. After consciously taking the time to do so, I slowly learned how to connect with my surroundings using a sense that we all seem to have lost touch with (especially us men, or so we are told). The one that I am referring to is the ability to really stop and listen.
I was asked the question; “what is your favourite sound in the bush?”, and I had to rather bashfully admit that I didn’t quite know. This inspired me to go out in search for it. Using a highly sensitive microphone I spent hours out in the field listening to the early dawn cacophony of crested francolins, woodland kingfishers, the cry of the African fish eagle and a variety of other bird calls. I also listened to impalas snorting, lions roaring, baboons barking and squirrels chirping. Amid all of this, a family group of elephants slowly ambled across an open clearing and the deep rumbling sounds emitted by the matriarch immediately caught my attention. As she rumbled, a young calf came running out of the tree line to assume its usual position at its mothers feet and the herd moved off into the distance. Click on the insert below to hear what I mean by this beautiful rumbling noise.
Elephants have an extraordinary ability to communicate via trumpets and rumbling sounds, but most of their communication is done through infrasound that humans simply cannot hear. The rumbling sound that in this instance was used to call the calf was the audible component of this subsonic communication. To hear sounds, elephants make use of small bones inside their eardrums to “hear” in the traditional sense, but also detect vibrations through a sensory pathway not connected to the ear, and sometimes both. The physiology of seismic communication in elephants is far beyond the scope of this post, but it has been suggested that elephants could detect subsonic sounds through their feet and trunk, which possess specialised cells that are extremely sensitive to touch. Researchers Katy Payne and Caitlin O’Connell have spent decades studying seismic communication in elephants, and suggest that elephants can detect sounds as low as 12 hertz (humans hear as low as 20 hertz) and can hear these low rumbles for as far as 10 km (6 miles) away.
To put this into perspective, the average human can hear another person talk normally from no further than approximately 25 m away. While this research was happening, a man named Randall Moore planned to relocate elephants that were kept in captivity in Canada to the wilds of Botswana’s Okavango Delta. While sailing across the Atlantic ocean, Randall and the crew noticed that the elephants were rumbling from below deck. After checking that the elephants had an adequate supply of food and water they returned to the ships cockpit, unsure of what had caused the commotion. Incredibly, they noticed that the ship’s sonar was picking up whales nearby. Whales use similar subsonic communication to elephants at a very similar frequency and it may be possible that the elephants and whales were tapping into the same frequency.
I was fascinated by all of this and decided to head out into the bush again to find a herd of elephants and listen to them. I tracked a herd down to a waterhole in the south of Londolozi. The herd was drinking and began to wet their skin to cool themselves down during the heat of the day. Suddenly, a few elephants stopped what they were doing, perked their ears up and then suddenly moved off, without a sound. I stayed at the waterhole for a while longer, only to be joined by a large elephant bull in musth about a half an hour later. It could be possible that the herd had heard this bull approaching through subsonic communication and decided to move off due to the presence of their small calves at foot. The subtlety of the interaction truly amazed me and revealed that their is often a lot more going on out there than we can see or hear. What is has shown me though is that the rumble of a herd of elephants is most certainly my favourite sound in the bush.