The International Union for Conservation of Nature added four out of six great ape species on their Red List of Threatened Species or critically endangered list. Experts cite illegal hunting as the major factor to the primates’ deteriorating status.

The Eastern Gorilla (Gorilla beringei), the largest living primate, suffered a 70 percent drop in population. As of now, researchers estimate that fewer than 5,000 of the Eastern Gorilla are left.

One of its subspecies, called Grauer’s Gorilla (G. b. graueri), suffered a 77 percent drop of its population since 1994 due to hunting. In that year, there were 16,900 Grauer’s Gorillas but in 2015, only 3,800 remained.

The other Eastern Gorilla subspecies, called the Mountain Gorilla (G. b. beringei), is doing better in comparison. The population has increased by up to 880.

The rest of the great apes that are on the brink of extinction are the Western Gorilla, Bornean Orangutan and Sumatran Orangutan. Meanwhile, the remaining two of the great apes, the Chimpanzee and Bonobo, are not critically endangered but they are still listed as endangered species.

While the news is grim, the IUCN has some good news to offer us.  The Giant Panda (Ailuropoda melanoleuca) is now listed as Vulnerable, an improvement from its endangered status previously.

Experts cite the Chinese government’s efforts to conserve the pandas are responsible for their improved status. Still, experts recognize that 35 percent of the animals’ bamboo habitat will disappear in the next 80 years due to climate change, consequently reducing the Giant Panda population in the future.

Nevertheless, the researchers assert that maintaining efforts to protect the species can help alleviate the forthcoming problem. Moreover, the Chinese government has announced plans to expand their policies to conserve pandas.

The Bridled Nailtail Wallaby (Onychogalea fraenata) and the Greater Stick-nest Rat (Leporillus conditor), both of which are endemic to Australia, have also experienced improvements due to conservation measures.  From being part of the Endangered list, the Bridled Nailtail Wallaby is now listed as Vulnerable. From Vulnerable, the Greater Stick-nest Rat is now listed as Near Threatened.