Evidence for echolocation in Asian shrew moles.

Echolocation is an adaptive sensory behavior that enables animals to navigate and perceive their surroundings in environments where vision is ineffective. This ability has been hypothesized to be widespread among nocturnal mammals with reduced eyesight, particularly in insectivorous moles. Here, we found that Asian shrew moles (subfamily Uropsilinae) produce ultrasonic pulses in the frequency range of 50∼100 kHz, which structurally resemble frequency-modulated echolocation calls found in other well-known echolocating mammals. Behavioral experiments further confirmed that Asian shrew moles use these ultrasonic pulses for echolocation. Analysis of the acoustic features of their ultrasonic calls, the morphology of their echolocation-related stylohyal bone, and tongue ligation experiments indicate that these Asian shrew moles produce echolocation calls using their tongues. Our findings demonstrate that Asian shrew moles represent a new echolocating mammalian lineage, indicating that echolocation independently occurred at least six times in mammals and underscoring the likelihood that the species diversity of echolocating mammals has been significantly underestimated.