While we humans need every organ of our body, animals seem to adapt and even thrive when they are missing body parts that we consider crucial to survive - There is the Borneo frog that breathes without lungs, the ice fish that has no hemoglobin and now, an earless frog that can hear perfectly.
And its not just any frog, but the world's tiniest one - The Gardiner's Tree Frog, that is endemic to the island of Seychelles and measures just a centimeter long. Like most animals it does not have an outer ear.
However the others adapt by transmitting sound through an eardrum that lays on the crown of their head. Just as in humans, the eardrum vibrates when it gets hit by sound waves and then sends them on to inner ear from where they are transmitted into electric signals that are then interpreted by the brain.
But such is not the case with this miniature frog. Though it has been known to croak and hear just like its counterparts, it has neither an eardrum nor, a middle ear. So how is it able to discern sounds? This mystery has confounded scientists for many years. Now in a report published in the September edition of the Proceedings of the National Academy of Sciences, a team of scientists led by Renaud Boistel seem to finally have the answer - These tiny frogs do not need ears because they can hear through their mouth!
The researchers from the French National Centre for Scientific Research and several universities began their investigation by placing speakers in the forest where the Tree Frogs reside and playing sounds that the frogs normally make, to see if they would react. To their surprise, they began hopping toward the speakers as if, responding to the sounds of a fellow frog.
In order to get to the bottom of the mystery, the scientists x-rayed one of the tiny frogs. However that was not much help since even its pulmonary system was poorly developed suggesting that the lungs were not helping with the hearing. The researchers then re-focused on its tiny head and after conducting several experiments reached the conclusion that the frog's hearing was occurring through its mouth. According to the scientists, the sound waves travel through the frog's mouth, where they are amplified by strategically placed bones, which transmit them to the inner ear and then onto the brain for interpretation, enabling the frog to hear as clearly as any other frog or animal, for that matter. Pretty amazing!
Resources: newswatch.nationalgeographic.com,livescience.com,popsco.com, pnas.org