Every morning Londolozi awakens to the sounds of the bushveld greeting the new day. The dawn chorus – as it has become known – includes hundreds of different bird species performing their daily ritual of announcing themselves to the world in the morning. As the day wears on, the sounds change: the hot midday brings with it the hum of cicadas and the occasional rustle of leaves in the marula trees as a gentle breeze brings relief from the heat.
The heat eventually gives way to the cool still evening, where one may hear lions roaring in the distance or the hyena’s mournful cry piercing through the still night. While nature’s sounds come from many sources, it is the animals in particular are responsible for creating the myriad of fascinating sounds we are privileged to hear. There is one animal, however, whose sounds go largely unnoticed by us humans. The African elephant has its own secret language that we are only just beginning to understand.
A few days ago I found myself surrounded by a herd of elephants and they were sauntering down a hill towards the Sand River for a drink. We had parked in the middle of a clearing and were able watch them approach without disturbing them at all. As the time ticked by, more and more elephants emerged from the Guarrie thicket. What we initially thought to be about 15 or so elephants turned out to be over 50 individuals! There were youngsters wrestling with each other and inquisitive little ones coming up to inspect the Land Rover all whilst the adult females fed nonchalantly on the dew covered grass. It was an amazing sight.
As we sat there in the clearing we became captivated by the sounds of the herd. There were loud cracks as the elephants broke branches off trees and fed on them. Low rumbles were traded between females as they seemed to converse with one another. Occasionally an elephant calf would let off a loud trumpeting bellow, voicing its disapproval after its mother denied it a chance to suckle.
The scene was peaceful.
Suddenly though, the mood all changed. Without warning, the elephants all bunched up close together and started to hurry towards the river. It was almost as though they had pre-choreographed this move because there was no apparent signal for them to change their behaviour. As the herd disappeared down the hill, a male elephant in musth (a state of heightened testosterone) appeared in the distance, clearly intent on following the herd. The male’s presence certainly could have cause the females to move off, but how did those females know that that big male elephant was around? How did the females and youngsters know to head towards the river ? How did that male know where to find the females ?
The answer to all these questions lies in elephant’s truly amazing ability to converse with each other using sound waves with a frequency so low, humans are incapable of hearing them. This form of communication is known as infrasonic communication and elephants are able to speak to other elephants over long distances. Scientific research suggests that, depending on the atmospheric conditions on the day, the distance over which elephants can communicate ranges from 30 to 300 square kilometres.
This ability to communicate seemingly silently (at least to our ears) over long distances explains why the behaviour of the elephants we were with changed so suddenly that morning. Elephants use their infrasonic communication for many reasons but it is mainly employed when the elephants are unable to see each other. Elephants may use infrasonic communication to keep track of their youngsters whilst feeding in thick areas, to alert the herd to danger or just to inform the herd of a change of plans. What is more, it is believed that the fatty pads in their feet help them to pick up on the vibrations created by the infrasonic waves, thereby enabling the elephants to essentially hear through their feet. There is still much to be discovered about this fascinating phenomenon but what we can say with certainty is that elephants can talk to each other at frequencies that humans are unable to hear.
On this particular morning however, the reason for the musth bull’s sudden apparition may have been caused by a member of the herd itself. You see, female elephants are only able to conceive onabout three days a year. This relatively short window of opportunity means that they don’t have time to waste when it comes to finding a potential mate. It is believed that a female entering into oestrous will advertise this fact to male elephants using infrasonic communication. The long distance communication ensures that males in musth far and wide will know where the female is and can then get to her before the three day period ends. By advertising her fertile state to males over a large range, the female improves her chance of finding a big dominant male with good genes, rather than just mating with the nearest male around. This process of casting a wide net, so to speak, is nature’s way of ensuring that the female will pass on the best possible genes to her offspring and that the genetic diversity of the species remains strong.
So, if you happen to find yourself surrounded by elephants as we were that day, try to observe their movements and see if you notice a change. That subtle change in direction or sudden stop may have been caused by a signal given off by one of the elephants that we are unable to hear. As you sit among these majestic beasts, open yourself up to listening to the sound of silence.