“From the most narrow possible point of view, it is in the best interests of mankind to minimize the losses of genetic variations. The reason is simple: they are potential resources. They are keys to puzzles which we cannot solve, and may provide answers to questions which we have not yet learned to ask.”

– Statement of Assistant Secretary of the Interior, regarding the proposed Endangered Species Act, H.R.  Rep. No. 93-412, pp. 4-5 (1973).

The modern Endangered Species Act (ESA) was enacted in 1973, replacing earlier versions passed in the 1960s, and has been amended periodically thereafter. The ESA creates a program for the conservation of threatened and endangered animals and plants and the habitats in which they are found. The Act is administered by the U.S. Fish and Wildlife Service and the U.S. National Oceanic and Atmospheric Administration Fisheries Service (collectively, “the Services”).

The Services maintain a worldwide list of endangered species, as well as a list of threatened species, and take species on or off the list as conditions affecting their long-term survival change. Categories of species include birds, insects, fish, reptiles, mammals, crustaceans, flowers, grasses, and trees. The Services also designate critical habitat for such species, which is defined as those geographical areas that are “essential to the conservation of the species.”  The public may petition for the listing or delisting of a particular species or habitat.

The ESA requires federal agencies, in consultation with one or both of the Services, to ensure that major actions they authorize, fund, or carry out are not likely to jeopardize the continued existence of any listed species, or result in the destruction or adverse modification of designated critical habitat of such species.  The law also prohibits any action that causes a “taking” (such as the injuring or killing) of any listed species, although it also empowers the Services to authorize “incidental” takes if certain conditions are met.

The ESA authorizes affected citizens and groups to bring  suit in federal court to enforce the consultation requirement. and to enforce the take prohibition, where the federal government has failed to take appropriate enforcement action.

Read more about the Endangered Species Act