Number of species assessed in the IUCN Red List and number of species held in ISIS zoos for each taxonomic class of terrestrial vertebrates.

*<p>The IUCN Red List refers to the categories of VU, EN and CR collectively as threatened species.</p>†<p>The reptile assessment by IUCN is not yet complete, so these results only refer to the species assessed in the IUCN Red List version 3.2 (2009).