The new listing means that all gorillas -including eastern and western gorillas -are now considered critically endangered.
The other subspecies of the eastern gorilla is the mountain gorilla (Gorilla beringei beringei), which is already listed as critically endangered. The population of mountain gorillas has, however, been increasing. There are now an estimated 880 individuals, up from about 300 in 2008, according to the IUCN's latest data.
The changes to the IUCN's Red List of Threatened Species were announced at the organization's World Conservation Congress in Hawaii.
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Among the other species whose threatened status was raised was the plains zebra (Equus quagga), which was once considered a species of "least concern" but is now "near threatened." The animal's population in Africa dropped by 24 percent over the past 14 years, from around 660,000 individuals to just over 500,000 animals, mostly due to hunting, according to the IUCN.
In a bit of good news, the giant panda (Ailuropoda melanoleuca), which had been listed as endangered since 1990, had its status downgraded to "vulnerable." The IUCN lauded conservation efforts that have helped boost the panda population in China, but warned that climate change could wipe out a large chunk of the bears' bamboo habitat during the next century.
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