Risso's Dolphin

Risso's dolphins were the small cetacean recorded most often on the 2003 offshore survey of Sri Lanka: six groups of 8 to 50 animals, about 153 in all, at depths of 800 to 2,000 m (de Vos et al. 2012). That fits the species' preference for deep water beyond the continental shelf and steep bottom slopes. All six were off the southeast coast, although earlier catch and sighting records show the species common and widespread around the island.

Most of the groups were travelling or bow-riding, but one was a large group of mating animals, which the authors called unusual. In one case Risso's dolphins were closely associated with a large group of Fraser's dolphins, a pairing reported elsewhere (de Vos et al. 2012).