Vocalization of echolocation-like pulses for interindividual interaction in horseshoe bats (Rhinolophus ferrumequinum).

Although much is known about the echolocation of horseshoe bats (Rhinolophus spp.), little is known about the characteristics and function of their communication calls. This study focused on a stereotyped behavior of a bat approaching a companion animal in the colony, and examined their interaction and vocalization during this behavior. The bats emit echolocation-like vocalizations when approaching each other and these vocalizations contain a "buildup" pulse sequence, in which the frequency of the pulse increases gradually to normal echolocation pulse frequencies. The results suggest that the echolocation-like pulses serve an important role in communication within the colony.