the ganges subspecies shows object-avoidance behavior in both the consistently heavily murky waters of its habitat and in clear water in captivity, suggesting that it is capable of using echolocation effectively to navigate and forage for prey. however, there is limited information on how extensively vocalization is utilized between individuals. this subspecies of river dolphin is capable of performing whistles but rarely does so, suggesting that the whistle is a spontaneous sound and not a form of communication. the ganges river dolphin most typically makes echolocation sounds such as clicks, bursts, and twitters. produced pulse trains are similar in wave form and frequency to the echolocation patterns of the amazon river dolphin. both species regularly produce frequencies lower than 15 khz and the maximum frequency is thought to fall somewhere between 15 and 60 khz.