According to Colin Butfield, head of campaigns at conservation charity WWF "It is a "uniquely bad situation". Meanwhile the vaquita a very rare porpoise discovered in 1958 and the Javan rhino are most in danger of going the same way. Sources reported that many other species including the Sumatran rhino, black rhino, amur leopard, forest elephant and Bornean orangutan are also considered critically endangered, some with fewer than 100 left.
Accordingly the International Union for Conservation of Nature (IUCN) produces a "Red List" dividing species of plant, mammal, bird, amphibian and marine life into seven categories from "least concern" up to "vulnerable", "endangered", "critically endangered" and "extinct" and presently it considers 5,583 to be critically endangered.
Meanwhile at least 26 were newly considered critically endangered in 2017,
having been in a less severe category the year before. Further a species with
500 animals left could be considered more endangered than one with only 300
left if that species is localized to one area and has a long reproductive cycle
meaning the population cannot quickly grow. Importantly compare creatures living
in tropical rain forests with more temperate forests. Further in a tropical
rain forest, there will be more species that don't exist anywhere else.