What is the function of the 'special vocalization' used by bats within their social groups?

Answer

To function as a unique acoustical signature and greeting

Each bat appears to have a 'special vocalization' that scientists believe acts as a unique acoustical signature and functions as a greeting when they settle into roosts.

What is the function of the 'special vocalization' used by bats within their social groups?
mammalflightabilitybatecholocation