Researchers in Brazil have discovered the first instance of amphibians utilizing “defensive ultrasound” to communicate. In the Amazonian jungle, they observed small leaf litter frogs making a loud, high-pitched noise while arching their backs and opening their mouths wide. Despite appearing to scream, humans could not hear anything when the researchers used high-frequency audio recorders to capture the sounds.
The frogs were emitting a frequency that was inaudible to humans but could serve as a response to predators or a call to arms to attract another animal to attack the predator. The distress call was recorded on two occasions, with a frequency range of 7 kilohertz (kHz) to 44 kHz. Humans cannot hear above 20 kHz, which falls into the ultrasound category. This discovery sheds light on the use of ultrasonic frequencies by animals in communication, a phenomenon that goes unnoticed by human ears. Whether it’s bats, whales, rhinos, dogs, pigeons or even cuttlefish many species utilize infrasonic and ultrasonic frequencies to interact with one another creating an invisible symphony that humans are unaware of in their daily lives.
