Bone conduction revealed: researchers explain the extraordinary hearing of elephants
July 19, 21:00
A team of American scientists has discovered that elephants can detect ground vibrations thanks to the size of their middle ear bones and a specialized muscle. The study showed that elephants communicate through airborne sounds over distances of up to 5 kilometers, but they also have a second communication channel—seismic waves transmitted through the earth. These vibrations travel from the feet, up through the legs, and via the skull bones into the inner ear, allowing elephants to pick up signals from 10 kilometers or more. This process is known as bone conduction.
The researchers worked with temporal bones from deceased elephants and human donors. The experiments revealed that:
- elephant ear bones vibrate most effectively at around 400 Hz,
- human ear bones vibrate at roughly 1.2 kHz,
- the elephant's stapes bone moved three to four times more actively than the human equivalent,
- the middle ear bones of elephants are nine times heavier,
- and their eardrums are seven times larger than those of humans.
Elephants also have a unique ability to voluntarily close their ear canal using a muscle, which can significantly enhance their bone-conduction hearing. As researcher Sunil Puria noted:
'We estimate that the ability to close the ear canals could boost their bone-conduction hearing by up to 30 times when perceiving these infrasonic frequencies.'
Indeed, elephants produce infrasonic signals in the 10 to 20 Hz range, which they can transmit over vast distances.
The findings were published in the journal Frontiers in Audiology and Otology, opening new avenues for understanding elephant communication and their sensory capabilities. This research underscores the uniqueness and complexity of elephant biology, showing that these animals can communicate and interact with their environment over much greater distances than previously known.
Studying elephant hearing is important not only for expanding knowledge of their biology but also for understanding their behavior in the wild. Insights into how elephants communicate across long distances could aid in developing conservation strategies for these animals and their habitats, as well as improve their protection in areas where they encounter human activity. The results may also inspire further scientific advances in zoology and ecology.
As researchers delve deeper into the intricate communication methods of elephants, it's important to consider how environmental factors, such as prolonged droughts, can influence their behavior. For instance, the ongoing changes in elephant behavior due to drought in Botswana highlight the adaptability of these animals in response to their surroundings, further enriching our understanding of their remarkable sensory capabilities.