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 and allowed the United States Fish and Wildlife Service to spend up to $15 million per year to buy habitats for listed species. It also directed federal land agencies to preserve habitat on their lands. The Act also consolidated and even expanded authority for the Secretary of the Interior to manage and administer the National Wildlife Refuge System. Other public agencies were encouraged, but not required, to protect species. The act did not address the commerce in endangered species and parts. In March, 1967 the first list of endangered species was issued under the act. It included 14 mammals, 36