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How Are Animals Declared Endangered?

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The Endangered Species Act -- designed to protect "critically imperiled species" from extinction -- was signed into law by President Richard Nixon in 1973. This landmark legislation represented the first comprehensive federal action for protecting plants and animals whose populations were jeopardized. It came after more than a half century of environmental activism calling for federal action after the near extinction of buffalo and the disappearance of the passenger pigeon in the early 1900s.

How It Is Administered

The Endangered Species Act is administered by two federal agencies -- the United States Fish and Wildlife Service and the National Marine Fisheries Service of the National Oceanic and Atmospheric Administration. FWS is responsible for all freshwater fish and all other species. NMFS is responsible for marine species. Species that occur in both fresh and marine water, such as sea turtles and Atlantic sturgeon, are managed jointly.

Previous Protection

While the Endangered Species Act was the first complete federal legislation creating the process by which any jeopardized species could be protected, it owes its origins to other previous, yet incomplete, federal legislation. The Lacey Act of 1900 prohibited interstate commerce of animals killed in violation of state game laws. It is now a part of the Farm Bill covering all fish, wildlife and plants. The Migratory Bird Conservation Act of 1929 and the Bald Eagle Protection Act of 1940 took steps toward protecting birds. In 1966, the Endangered Species Preservation Act allowing for the listing of U.S. native animal species as endangered. It gave the Secretary of the Interior purchasing power to buy habitat lands -- a key move forward in protecting species, according to the Thoreau Institute. Foreign species were added to the ESPA in 1969 in an effort to protect whales and a new series of marine animals were added to protection afforded under the Lacey Act. Intense political pressure from environmental activists spurred Nixon to instruct congress to write a comprehensive endangered species act that would outline the qualifications for protection and what actions the federal government would take.


Species can be listed as endangered based on several reasons: If a large portion of its habitat is destroyed, if it has been overharvested for commercial, scientific research or educational purposes, or if disease, predation or other man-made factors threaten the stability of the population. The process for determining if a species should be listed as endangered is complicated, as each species requires its own specialized considerations.

Individuals Can Submit Petition

The flexibility of the Endangered Species Act allows for an individual to submit a petition to the Secretary of Interior requesting that a species be considered endangered. Depending on the species, staff from either the U.S. Fish and Wildlife Service or the National Marine Fisheries Service has 90 days to evaluate whether the petition has merit continuing the process. After this, it can take up to a year to complete the investigation.

Candidate Conservation Process

The two federal agencies overseeing administration of the Endangered Species Act can declare a species as endangered. Sufficient data suggesting endangerment is required before the species is listed in what is known as the Federal Register. This public document is where potential listings are made available for anyone to review and comment on during a 60-day period. Federal hearings are held at which anyone can testify regarding the effects of declaring the species in question as endangered. Officials within whichever agency monitors the species then make a ruling as to whether the species will be considered endangered. This process can take up to a year to complete.

IUCN Red List of Threatened Species

The International Union for Conservation of Nature and Natural Resources -- founded in 1963 -- is a group of 800 scientists worldwide who evaluate threats to specific populations of plants and animals. Its Red List of Threatened Species is actually a series of lists produced according to population threats by geographic areas. These lists are promoted from the group's London, England, offices and provided to governments worldwide to aid in policy making and species protection. The IUCN website indicates that bird species were evaluated in 1988, mammal species were evaluated in 1996 and plants were evaluated in 1997. The group's stated goal is to update status for each species every five years.