There are six great apes: Eastern gorilla, Western gorilla, Bornean orangutan, Sumatran orangutan, common chimpanzee and bonobo.
The Eastern gorilla now joins three other great primates, as being critically endangered, and added to the <a href="https://www.iucn.org/news/four-out-six-great-apes-one-step-away-extinction-%E2%80%93-iucn-red-list">red list</a> posted by <a href="https://www.iucn.org/">International Union for Conservation of Nature</a>. Other critically endangered great apes are Western gorilla, Bornean orangutan and Sumatran orangutan. The remaining two, common chimpanzee and bonobo are listed as endangered.

The Eastern gorilla is divided into two subspecies: Grauer's gorilla and mountain gorilla. There are only about 800 of mountain gorillas left  and about 3,800 Grauer's gorillas. Their number have been decimated due to illegal capturing and hunting for meat. 

http://i1243.photobucket.com/albums/gg541/Peter_April/grauer_s_gorilla_zpsxafggyw9.jpg
[ Grauer's gorillas. Picture <a href="http://www.wwf-congobasin.org/?264831/Catastrophic-collapse-of-Grauers-gorillas">source</a> ]

http://i1243.photobucket.com/albums/gg541/Peter_April/mountain_zpscvx3yzn3.jpg
[ Mountain gorillas. Picture <a href="http://deforestation.besaba.com/endangered.php">source</a> ]

Numbers of Sumatran and Bornean orangutans have dramatically declined due to the effect of destruction of their natural habitat caused by deforestation. Orangutan's native rain forest has been systematically destroyed through logging (illegal and legal) and transformation to agricultural land or palm oil plantations.
Palm oil companies are the major contributor to destruction of rain forest in Sumatra and Borneo. Palm oil is used in many cosmetics and food products. 

http://i1243.photobucket.com/albums/gg541/Peter_April/Bornean-Orangutan_zps0szkuqfl.jpg
[ Bornean orangutans. Picture <a href="http://www.hdimagez.com/download-20-bornean-orang-utan-wallpapers/">source</a> ]

http://i1243.photobucket.com/albums/gg541/Peter_April/sumatran-orangutan_zpslmqrxkhw.jpg
[ Sumatran orangutans. Picture <a href="http://true-wildlife.blogspot.co.uk/2011/03/sumatran-orang-utan.html/">source</a> ]

Common chimpanzee and bonobo are considered to be under threat of extinction. The main threats to these species are destruction of habitat, commercial poaching, disease and human population growth.

http://i1243.photobucket.com/albums/gg541/Peter_April/chimpanzee_zpswgebepde.jpg
[ Common chimpanzees. Picture <a href="https://simple.wikipedia.org/wiki/Chimpanzee/">source</a> ]

http://i1243.photobucket.com/albums/gg541/Peter_April/bonobo_zps14oyfov2.jpg
[ Bonobos. Picture <a href="http://bonobohub.com//">source</a> ]

----

It is heartbreaking to see what is happening to these beautiful species.
-logic