Frog species heard by mouth

A small frog in Africa can use oral cavity to receive sound, while frogs are often thought to be incapable of hearing because there is no middle ear and eardrum.

Amphibian species such as frogs are often considered to be incapable of hearing, they do not have the middle ear or eardrum to receive sound waves. But the strange thing is that they can still make a crack and hear the cries coming from the same kind.

In a new study, scientists used X-rays to look inside the heads of Gardiner frogs in the Seychelles Republic, and discovered they used the oral cavity to amplify the sound that was transmitted into the inner ear through connective tissue.

Gardiner frog species on Seychelles island.(Photo: CNRS)

Most quadruped animals have small middle ears, small bones. They receive vibrations from the eardrum and transmit sound from the air into the cochlea containing fluid."However, there are frogs who are clamoring like other frogs with no middle ear. This may seem contradictory , " said Renaud Boistel, head of the research at the French National Center for Scientific Research in Paris , to speak.

According to Livescience, to prove Gardiner frogs use sound to communicate, scientists put speakers in natural forests in Seychelles and turned on some frogs. As a result, male frogs immediately responded to the recorded sounds. That proves that they hear sound in the recording.

By studying images of X-rays and numerical simulations, the researchers found Gardiner frogs received sound through their heads. Their mouths amplify the frequency and sound that is transmitted through the bones and tissues in the skull into the inner ear.

"The combination of oral cavity and bone conduction allows Gardiner frogs to hear effectively without using the middle ear. This suggests that the mechanism of hearing adaptation is the result of evolution." Boistel said.