Natures wonders: two sounds from bat larynx (Introduction)

by David Turell , Wednesday, November 30, 2022, 21:11 (512 days ago) @ David Turell

High pitched and low growls:

https://www.sciencedaily.com/releases/2022/11/221129143818.htm

"Bats use distinct structures in the larynx to produce high-frequency echolocation calls and lower-frequency social calls, according to a new study. The structures used to make the low-pitched calls are analogous to those used by death metal vocalists in their growls.

"Echolocating bats have an extremely large vocal range of 7 octaves, compared to just 3 to 4 octaves for most mammals, including humans. Their echolocating calls and social calls range between 1 and 120 kilohertz, making them unique among mammals. To understand how different vocal structures allow bats to create such a wide range of calls, researchers extracted the larynx from five adult Daubenton's bats (Myotis daubentonii), mounted and filmed them at 250,000 frames per second while applying a flow of air to mimic natural vocalization. They then used machine learning to reconstruct the motion of vocal membranes that were obscured by other structures.

They found that air pressure generated self-sustaining vibrations in the vocal membrane at frequencies between 10 and 70 kilohertz, sufficient to produce high-frequency echolocation calls. In contrast, thick folds of membrane just above the vocal cords, called "ventricular folds," vibrated at frequencies between 1 and 3 kilohertz, and are likely involved in producing the animals' lower-frequency social calls. Some humans also use their ventricular folds to produce low-frequency vocalizations, such as death metal growls and Tuvan throat singing."

Comment: this is not something natural selection can purposely create, just because of useful need. It is designed