South Asian river dolphin The sphincter-like structure is capable of sensing light, and may be able to sense the direction from where the light was emitted. However, the muddy waters, or low light conditions, that the "Platanista gangetica" inhabit negate the use of the little vision that remains. 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
Endangered Species Act of 1973 occurred by 1963 to habitat preservation instead of take regulations. A provision was added by Congress in the Land and Water Conservation Fund Act of 1965 that provided money for the "acquisition of land, waters...for the preservation of species of fish and wildlife that are threatened with extinction." The predecessor of the ESA was the Endangered Species Preservation Act of 1966 (P.L. 89-669 ). Passed by Congress, this act permitted the listing of native U.S. animal species as endangered and for limited protections upon those animals. It authorized the Secretary of the Interior to list endangered domestic fish and wildlife