Discrimination of fast click series produced by tagged Risso's dolphins (Grampus griseus) for echolocation or communication

• DOI: 10.1242/jeb.144295
• Publication Date: 2016-07-12T05:15:06Z
• Authors: P. Arranz; S. L. DeRuiter; A. K. Stimpert; S. Neves; A. S. Friedlaender; J. A. Goldbogen; F. Visser; J. Calambokidis; B. L. Southall; P. L. Tyack
• Keywords: Human echolocation; Jerk

Early studies that categorized odontocete pulsed sounds had few means of discriminating signals used for biosonar-based foraging from those communication. This capability to identify the function is important understanding and interpreting behavior; it also essential monitoring mitigating potential disturbance human activities. Archival tags were placed on free-ranging Grampus griseus quantify discriminate between echolocation-based Two types rapid click-series sounds, buzzes burst pulses, identified as produced by tagged dolphins classified using a Gaussian mixture model based their duration, association with jerk (i.e. change acceleration) temporal click trains. Buzzes followed regular echolocation clicks coincided strong signal accelerometers tag. They consisted series averaging 359±210 (mean±s.d.) an increasing repetition rate relatively low amplitude. Burst pulses short 45±54 decreasing longer inter-click interval less likely be associated signal. These results suggest longer, lower amplitude, jerk-associated are in this species capture prey, mostly during bottom phase dives, seen other odontocetes. In contrast, shorter, isolated generally emitted while at or near surface outside direct, known context.