The Endangered Species Act of 1973 is one of the dozens of United States environmental laws passed in the 1970s. Signed into law by President Richard Nixon on December 28, 1973, it was designed to protect critically imperiled species from extinction as a "consequence of economic growth and development untempered by adequate concern and conservation."

The Act is administered by two federal agencies, the United States Fish and Wildlife Service (FWS) and the National Oceanic and Atmospheric Administration (NOAA).

Endangered Alabama beach mouse
Endangered Alabama beach mouse Photo credit: USFWS
Endangered black-footed ferret Mustela nigripes
Endangered black-footed ferret (Mustela nigripes) Ryan Hagerty/USFWS
Endangered red wolf Canis rufus
Endangered red wolf (Canis rufus) Steve Hillebrand/USFWS
Endangered San Joaquin kit fox Vulpes macrotis mutica
Endangered San Joaquin kit fox (Vulpes macrotis mutica) Heather Bell/USFWS
Endangered, threated gray wolf Canis lupus
The wolf population in Isle Royal National Park could go extinct in a few years, according to a recent study. Credit: John and Karen Hollingsworth, U.S. Fish and Wildlife Service. USFWS
Mexican wolf
Mexican wolf Jim Clark/USFWS
Southern Idaho ground squirrel Spermophilus brunneus endemicus, candidate
Southern Idaho ground squirrel (Spermophilus brunneus endemicus), candidate Dennis Mackey/USFWS
Threatened grizzly bear Ursus arctos horribilis, Yellowstone National Park
Threatened grizzly bear (Ursus arctos horribilis), Yellowstone National Park Terry Tollefsbol/USFWS
Polar bear Ursus maritimus
Polar bear (Ursus maritimus) USFWS
Otters Come Back From Brink of Extinction
Otters Come Back From Brink of Extinction. Lilian Carswell/USFWS
Washington ground squirrel Urocitellus washingtoni, candidate
Washington ground squirrel (Urocitellus washingtoni), candidate Scott McCarthy/USFWS