The dolphins then play with the fish like a cat with a mouse before discarding them. These fisherman say they observe copulation almost daily during this period, and fights between males are also often observed. Coitus is preceded by much play including chases or jumps with the partners often leaping out of the water, belly to belly. During coitus, other members of the group swim around the mating pair. The main sonar signal consists of only a few cycles of a dominant frequency of around 60 kHz.
Pulse trains are rather regular in nature.
No audible whistles or pure tones have been recorded. Baird et al. They have been found as far as 1440 km upstream and can live permanently in freshwater. Jefferson et al. In one report, fisherman in Burma were observed to attract irrawaddy dolphins by tapping the sides of their boats with oars.