The International Union for Conservation of Nature (IUCN) has declared the Western Black Rhino of Africa officially extinct and says two other subspecies of rhinoceros are close to meeting the same fate.

According to IUCN’s updated Red List of endangered species about a third of the 61,900 species now catalogued by the IUCN are classified as “vulnerable,” “endangered,” “critically endangered,” or extinct, with some groups, such as amphibians and reptiles, in particularly rapid decline.

“Human beings are stewards of the earth and we are responsible for protecting the species that share our environment,” said Simon Stuart, head of the IUCN Species Survival Commission, in a statement.

“In the case of both the western black and the northern white rhinos the situation could have had very different results if suggested conservation measures had been implemented.”

“The world is full of marvelous species that are rapidly moving towards becoming things of myth and legend,” said the IUCN’s Jean-Christophe Vie.