Elephant Anatomy - Hearing System

For many years, it was thought that the hearing abilities of elephants was limited and that they were only capable of hearing sounds that were close by or very loud. Other theories claim that elephants do hear well, but only as a result of their large pinnae and that these function as large amplifiers, directing the sound into the ear and minimising the interference of other background noises. However, the pinnae are designed primarily for cooling the elephant (temperature control) and for conveying moods and messages to other elephants as a form of communication.

TResearch has shown that elephants are actually capable of communicating to others that are a considerable distance away. The method of communication that they use is called infrasound or infrasonic communication. The infrasonic sound is a level of sound waves that humans cannot hear with their own, unaided ears. Devices have been designed, which allow us to hear these noises. Still, our understanding of the intricacies of this communication is limited.

Elephants can communicate by this means over vast areas. According to research conducted by David Larom and Michael Garstang, elephants are able to communicate with others who are within a radius of 100 square kilometres. During the African day, the air temperature within 300m of the ground causes inverted low-frequency sounds to dissolve into the atmosphere. However, when the temperature drops, these sounds are reflected back onto the ground so that the sound carries better. So, sunset is the best time for elephants to communicate over large areas.

Of course, night time would be the perfect time to communicate in terms of coverage as the temperature on the surface of the ground would be at its coolest and sound would be conducted optimally. But, due to the prevalence of predators during the evening, elephants are wise to keep quiet, communicating rather when lions are asleep during the day. Elephants negotiate on the quality of their communication for the safety of the herd.

Infrasound communication allows for distress signals to be carried for many kilometres. This alerts fellow elephants to dangers or urgent pleas for assistance, or informs them of a female sending out estrus calls. This accounts for the sudden reaction in elephants when the human observers are unaware of any sort of sound. When an elephant has heard an infrasound call, it will immediately stop what it is doing in order to pay attention. Females make use of this ability in sending out estrus calls as the time in which they can mate is limited. Communicating their availability allows bulls from a far wider area to have the opportunity to mate with her, increasing her chances of bearing a strong, healthy calf (as she decides which bull she will accept).

This method of communication also strengthens bonds among the families and herds in a specific area, eliminating or reducing the need to travel vast areas to communicate and so reducing unnecessary energy expenditure. Such wise utilisation of natural abilities again demonstrates the intelligence that sets the magnificent elephant apart from its contemporaries.