Endangered species

Definition

A species classified by the IUCN Red List or other authoritative body as facing a very high risk of extinction in the wild in the near future. This designation (IUCN category EN) sits between Vulnerable and Critically Endangered and triggers legal protections, recovery planning, and conservation-reliant management such as captive breeding, habitat restoration, or invasive-species control. Status is assessed using quantitative criteria including population size, rate of decline, geographic range, and probability of extinction within specified timeframes.

Etymology

From 'endanger' (to put at risk) + 'species' (Latin species, kind or appearance)

Example

The American burying beetle (Nicrophorus americanus), once widespread across eastern North America, is now endangered due to habitat fragmentation, reduced carrion availability, and pesticide use; recovery efforts involve captive propagation and reintroduction to historic prairie and forest habitats.

Synonyms

• EN (IUCN category)

Related Terms

• threatened species
• critically endangered
• conservation status
• IUCN Red List
• extinction risk
• habitat fragmentation
• captive breeding
• species recovery plan

Usage Notes

In strict IUCN usage, 'Endangered' is a specific category (EN) with quantitative thresholds (e.g., ≥50% population decline over 10 years or three generations, or <2,500 mature individuals with ongoing decline). The term is often used more loosely in legislation (e.g., U.S. Endangered Species Act) where 'endangered' and 'threatened' have statutory definitions that differ slightly from IUCN criteria. Not all rare or declining species qualify; many insects remain 'Data Deficient' due to lack of survey effort. Contrast with 'extinct in the wild' (survives only in captivity) and 'vulnerable' (lower extinction risk).