Pod-specific call repertoires and compound calls of killer whales, Orcinus orca Linnaeus, 1758, in the waters of northern Norway

Abstract

Underwater vocalizations of 9 photoidentified pods of killer whales (Orcinus orca) were recorded in northern Norway from 1986 to 1992. In total, 34 call types and 20 subtypes were identified from the recordings. The pods had repertoire sizes ranging from 3 to 16 call types (average 9.0 call types). Pod-specific calls were found in 6 of the 9 pods. All pods had a unique repertoire combination. This study thus supports the hypothesis that vocal traditions are characteristic of killer whales. Some calls were combined, forming a total of 21 different syntactically organized compound calls. The function of this was not known, but it was suggested that adding size and flexibility to a small and rigid vocal repertoire may be advantageous.