clhs sciblog

A special species of frogs was discovered. They communicate using purely ultrasonic calls. The frequencies are too high to be heard by humans. The frog lives only on the Southeast Asian island of Borneo. The frogs can hear sounds up to 38 kilohertz. Humans can only hear up to about 20 kilohertz. This species of frogs, called Huia cavitympanum, has eardrums recessed in the side of the skull, while most of 5,000 frog species worldwide have eardrums that are flat on the side of the head. Huia cavitympanum produces some audible calls and others that are ultrasonic. When you look at the frog, you can tell it is vocalizing because the vocal pouches pulsate. But you can’t hear any sound. Peter Narins and Victoria Arch have a theory. They think that the frogs started to use higher frequencies in their communication to avoid interference of sound produced by rushing water in the lower-frequency range. However, high-frequency sounds don’t transmit as far. If they produce lower-frequency calls, they can transmit calls over a greater distance, so they can communicate with frogs that are farther away from them. But if they produce ultrasonic sounds, they might be able to communicate better over the background noise.

Read the article here.