The magic of elephant ears

By Julia Schmitt

Like humans elephants are highly social animals and sound plays an important role in their lives. Low-pitched sound waves are long and bend around objects in the landscape. These waves can travel across very long distances and there is evidence elephants use these sounds to detect storms and each other.

Elephants produce many sounds including low-pitched ‘rumbles’ and scientists have used mathematical models to show these rumbles can travel up to 10km!

Elephants’ ears are well suited for detecting these sounds. Their large outer ear funnels sound into their hearing organs and helps them work out where sound is coming from. They also have an eardrum that has an area of 8cm. To put this in perspective a human’s eardrum is only 0.5cm²!

Elephant society is matriarchal with males leaving the herd at puberty. Female elephants bond strongly despite herds being separated by vast distances. Scientists have used huge microphones to project recorded elephant rumbles. They found females responded best to other females they knew suggesting elephants recognize their friends by voice. Just like humans it seems lady elephants are just as good at gossiping.

Rumbles are also used for reproductive purposes. Females rumble when fertile and there is a male already with the herd. This incites male competition to ensure the females get the best possible man elephant. Only male elephants up to the challenge respond to these calls suggesting non-dominant males know when a female is out of their league.

Elephants also use their super hearing to know when rain is on the way because thunderstorms emit loud low frequency sounds.  Mathematical modeling based on elephant ear anatomy and GPS tracking of African elephants show they can detect thunderstorms over 100kms away. That’s further than the distance between Melbourne and Geelong or Brisbane to the Gold Coast!

Scientists are now looking at using this research to aid elephant tracking and conservation. Knowing the environmental signals that trigger elephant migration is critical in keeping these amazing animals alive.