Dolphins send out sharp ?clicks?, and then try to catch the echoing sound of those clicks. Do you know why? Well, this is how they locate objects in the water and this is how they virtually ?see? in the dark and can even make a difference between small and large fish! These sound beams they send out can be used as weapons to stun their prey. The Gangetic river dolphins are blind but are still able to locate both prey and danger through echo-location. Some dolphins have as many as 200 teeth. The Gangetic river dolphin, Platanista gangetica, which inhabits the Ganges and Brahmaputra river systems has as many as 120 teeth! It feeds mainly on fish and shrimp and hunts either in the evening or at night. In size, it is about 1.5 to 2.4 m in length, which includes a ?beak? that?s about 45 cm! A rounded forehead going up sharply from the beak, and gracefully ending in a horizontal tail fluke defines the ?order? of animals.