Quirks & Quarks

Listening for elephant earthquakes might help us save pachyderms from poachers

Low-frequency vibrations from elephant footfalls and vocalizations are being monitored using seismic equipment
Researchers from the UK used seismic detectors normally used to listen for earthquakes to monitor elephant movements at a distance. (Illustration by Robbie Labanowski)

Elephant sound: How low can you go?

One of the surprising facts about elephants is that they can communicate both above and below ground. Now, scientists have figured out how to listen in on their subterranean signals.

Elephants produce quite a lot of sound through the ground, though we humans can't hear it. Their heavy footsteps produce powerful vibrations, and their loud, low-frequency vocalizations are also transmitted through the ground. Biologists suspect the pachyderms can detect these vibrations and vocalizations over great distances through their feet.

This sound of the vibrations created by elephant footsteps was captured by Dr. Beth Mortimer using seismic equipment. It has been shifted in frequency to be made audible.

Listening in on elephant earthquakes

Using this approach, we could get real-time information where we might be able to intervene in a situation where we think there might be panic running.- Beth Mortimer

Dr. Beth Mortimer is an 1851 research fellow at the University of Oxford and has been studying elephant vibrations in her research. She wanted to see if she could detect those vibrations—footsteps and vocalizations—to remotely monitor elephant behaviour, and maybe even to catch poachers.

The vibrations an elephant generates through its movements can be used to determine its behaviour. (Illustration by Robbie Labanowski)

"Using this approach, we could get real-time information where we might be able to intervene in a situation where we think there might be panic running."

She used tools designed to detect earthquakes, and was able to record the seismic signal of elephant behaviours like walking, feeding, and talking, and correlate it to different vibration patterns.

"The idea is, if we could get a larger data set where we're able to say these behaviours generated this type of recording, then we might be able to identify which characteristics of a recording are more likely to tell us this is an elephant, or this is an elephant running," said Mortimer.

Connecting sound and behaviour

"Using that information, potentially then we can do this blind, so we can do this at further distances and then identify the behaviours just based on the seismic recording."

Her team created computer models with the recordings to estimate how far these vibrations might travel under different physical conditions. The farthest distance was around six kilometers under favourable conditions (sandy terrain and low noise) to allow detection of the vibrations and discrimination between the different behaviours. 

Going forward, Mortimer hopes to use the method to create an alarm system to protect elephants from poachers. By detecting the characteristic seismic signal of "panic running," triggered by the presence of poachers, they could warn game wardens or other authorities that the elephants were under attack.