Abstract: Bottlenose dolphins (Tursiops truncatus) communicate using various acoustic signals, including whistles and pulsed sounds. Many studies have been conducted on dolphin whistle development over a long span, but little research has been done on sounds produced by neonatal dolphins just after birth. For this reason, we studied the acoustic characteristics of underwater sounds produced by two neonatal dolphins. Both whistles and burst-pulses were identified as neonatal sounds at 1.5 h after birth. Whistles became longer by the hour. Whistle durations were highly correlated with respiration intervals. The neonate randomly produced various types of whistles, but no dominant whistles were documented. There were significant differences between neonates in the proportion of whistles to burst-pulses used, and also in the acoustic characteristics of their whistles. Acoustic characteristics that are unique to each individual neonate might help a mother dolphin to recognize her neonate.

Key Words: BOTTLENOSE DOLPHIN; TURSIOPS TRUNCATUS; BURST-PULSES; NEONATES; PARENT-OFFSPRING RECOGNITION; DEVELOPMENT; WHISTLES

Document Type: Research article

DOI: 10.1578/AM.31.2.2005.248

Page Numbers: 248 – 257