High‐frequency whistles of Irrawaddy dolphins (Orcaella brevirostris) recorded in Brunei Bay

• Published in: Marine mammal science Vol. 36; no. 3; pp. 846 - 857
• Main Authors: Jiang, Ying, Liu, Zongwei, Yang, Chunmei, Lü, Lian‐gang, Yu, Xiaolin, Huang, Longfei, Zhang, Xuelei, Yang, Zhiguo, Yang, Guangbing, Sun, Lu, Jaaman, Saifullah Arifin, Muda, Azmi Marzuki
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.07.2020; Wiley Subscription Services, Inc
• Subjects: Aquatic mammals; Broadband; Brunei Bay; Cetacea; Dolphins; Dolphins & porpoises; Frequency ranges; Freshwater mammals; high‐frequency whistle; Irrawaddy dolphin; Marine mammals; Orcaella brevirostris; ultrasonic frequency range; Vocalization behavior; Brunei
• ISSN: 0824-0469; 1748-7692
• DOI: 10.1111/mms.12681

Studies of the whistles of Irrawaddy dolphins (Orcaella brevirostris) have traditionally been restricted to analyses of the human audio range (below 20 kHz). In this study, broadband acoustic recordings of Irrawaddy dolphins in Brunei Bay were obtained using a sampling frequency of 512 kHz. Among the 984 whistles collected, eight (0.81%) high‐frequency whistles were detected with fundamentals above 18.4 kHz, which is the reported maximum frequency. Four (50%) of these whistles had the entire fundamentals in the ultrasonic frequency range (above 20 kHz), where 52.3 kHz was the maximum frequency. This is the first description of the ultrasonic components of Irrawaddy dolphin whistles. Our findings demonstrate that the whistles of Irrawaddy dolphins span a wider frequency range than previously published.