The Endangered Species Act (ESA) provides a framework to protect and recover species at risk of extinction, both domestically and abroad. Enacted in 1973, it has been credited with saving 99 percent of listed species from extinction and is hailed as the world’s strongest conservation law.
To qualify for ESA protections, a species must first be listed under the law as either endangered or threatened. “Endangered” means a species is in danger of extinction throughout all or a significant portion of its range. “Threatened” means a species is likely to become endangered within the foreseeable future.
A listing evaluation may be initiated by a petition from an individual, organization, or state agency, or through the federal government’s own candidate assessment programs. The US Fish and Wildlife Service makes listing determinations for terrestrial species, while the National Marine Fisheries Service makes listing determinations for marine species. The ESA requires that listing decisions be based solely on the best scientific and commercial data available.
By law, a species usually must be listed if it is deemed threatened or endangered due to any of the following five factors: (1) destruction, modification, or curtailment of habitat or range; (2) overutilization for commercial, recreational, scientific, or educational purposes; (3) disease or predation; (4) inadequacy of existing regulatory mechanisms to protect the species and its habitat; or (5) other natural or manmade factors affecting the species’ continued existence.
The ESA currently protects approximately 1,700 domestic and 700 foreign species. The chart below includes all animal species currently listed under the ESA. Please see the key below for an explanation of the abbreviations used in the chart. (Last updated April 2024.)
- Endangered = Endangered species
- Threatened = Threatened species
- Endangered (S/A) = Endangered based on similarity of appearance to an existing listed species
- Threatened (S/A) = Threatened based on similarity of appearance to an existing listed species
- XE = Essential experimental population
- XN = Nonessential experimental population