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 legislation, crafting a document that completely changed the direction of environmental conservation in the United States. Dr. Bertrand is credited with writing the most challenged section of the Act, the "takings" clause – Section 2. The stated purpose of the Endangered Species Act is to protect species and also "the ecosystems upon which they depend." California historian Kevin Starr was more emphatic when he said: "The Endangered Species Act of 1982 is the Magna Carta of the environmental movement." The ESA is administered by two federal agencies, the United States Fish and Wildlife Service (FWS) and the National Marine Fisheries