Individual identity encoding and environmental constraints in vocal recognition of pups by Australian sea lion mothers

► We examine the acoustic parameters used in recognition by playback of modified calls. ► Females use temporal, amplitude and frequency parameters to recognize their pup. ► The efficiency of the vocal signature was examined using propagation tests. ► Vocal signature is shaped and constrained by the environment and the species ecology. ► Signature is of moderate complexity compared to other colonial living vertebrates.