How do bat nose leaves relate to echolocation signals?

The nose leaf is a specialized facial structure composed of skin and connective tissue that surrounds the nostrils of many bat species. Its presence is strongly correlated with the nasal emission of echolocation signals.1

While the exact function of the nose leaf is not known for certain, it is believed to influence the bat's sound output. Researchers hypothesize that the structure may help channel or narrow the beam of the emitted sonar pulses, potentially aiding in more precise orientation and target detection. Because these bats emit their orientation signals through the nose rather than the mouth, the nose leaf likely acts as a physical modifier for the sound waves as they leave the nostrils. However, scientific evidence regarding the specific mechanics of how the nose leaf shapes these signals remains sparse.213