Since 1994, the International Union for the Conservation of Nature (IUCN) has been compiling a list of endangered species. Today, the IUCN Redlist is the standard for finding out about the status of more than 49,000 endangered species.
The same article described a major assessment of life's different animal groups and the news is not good. For example, 25% of assessed mammals and 41% of assessed amphibians are threatened. Why it went under the title "Are we in the midst of a sixth extinction?" is a mystery when the answer is obvious.