Department of Marine Resources and Energy, Tokyo University of Marine Science and Technology, 4-5-7, Konan, Minato-ku, Tokyo, 108-8477, Japan.
Cetacean Research Center, Graduate School of Bioresources, Mie University, 1577, Kurimamachiya-cho, Tsu-shi, Mie, 514-8507, Japan.
J Acoust Soc Am. 2019 Jul;146(1):409. doi: 10.1121/1.5116692.
Pacific white-sided dolphins are a group-living species and appear to exchange "contact calls" to maintain group cohesion. The aim of this study was to find and characterize their contact calls. Calls were recorded from two females at Osaka Aquarium KAIYUKAN (OAK) and three females at Izu-Mito Sea Paradise (IMSP). Because they often produced pulsed calls consecutively, a "pulsed call sequence" was defined as three or more successive pulsed calls occurring within 325 ms, which was calculated using a bout analysis. The pulsed call sequences increased during separation periods and decreased during reunions and were used for vocal exchange, suggesting that the sequences are contact calls in Pacific white-sided dolphins. Most of the pulsed call sequences were classified into unique types; several stereotyped, repeated patterns were found. One sequence type was found at OAK and the two dolphins shared the type; they exchanged sequences with type matching. On the other hand, three sequence types were found in IMSP and the three dolphins shared all of the types; however, each dolphin preferentially used different types and frequently exchanged with their own favorite types but not with type matching. These results suggest that the sequence type may function as an individual and/or group identity.
太平洋白海豚是一种群体生活的物种，它们似乎通过交换“接触叫声”来维持群体凝聚力。本研究旨在寻找并描述它们的接触叫声。叫声是从大阪海游馆（OAK）的两只雌性海豚和伊豆水族馆（IMSP）的三只雌性海豚中录制的。因为它们经常连续发出脉冲叫声，所以将“脉冲叫声序列”定义为在 325 毫秒内连续发出三个或更多的脉冲叫声，这是通过回合分析计算得出的。在分离期间，脉冲叫声序列增加，在团聚期间减少，这些序列被用于声音交流，表明它们是太平洋白海豚的接触叫声。大多数脉冲叫声序列被分类为独特的类型；发现了一些刻板的、重复的模式。一种序列类型在 OAK 被发现，两只海豚共享该类型；它们通过匹配类型来交换序列。另一方面，在 IMSP 发现了三种序列类型，三只海豚共享所有类型；然而，每只海豚都更喜欢使用不同的类型，并经常与自己喜欢的类型进行交换，而不是与匹配类型进行交换。这些结果表明，序列类型可能作为个体和/或群体的身份。
