Table 1 Extinction rates calculated by cohort analysis and fractions of species that are critically endangered (CR).

Data from (13, 37, 50, 51). Bird species thought to be “possibly extinct” are counted as extinctions.

When
described
SpeciesExtinctionsSpecies-yearsExtinction
rate
CR% CR
Birds
Before 19008922891,812,897491231.4
1900 to present12301398,334132604.9
Amphibians
Before 1900143714212,34866372.6
1900 to present497222206,1871074839.7
Mammals
Before 1900298336500,25272702.3
1900 to present252343176,8582431265.0