Changing durations of southern resident killer whale (Orcinus orca) discrete calls between two periods spanning 28 years

摘要

Killer whales vocalize in order to navigate, forage, communicate, and engage in social behavior. The sounds made by killer whales are classified into three types of vocalizations: clicks, whistles, and discrete calls. Discrete calls are pulsed calls that have been categorized into stereotyped call types (Ford 1987). Discrete calls are easily differentiated by the human ear and also provide a unique spectrographic structure.