Grauer's Gorilla Silverback (image) Wildlife Conservation Society Share Print E-Mail Caption The Grauer's gorilla is the world's largest gorilla (silverbacks such as this one can grow up to 500 pounds in weight) as well as the least known due to the insecurity of its range in the eastern Democratic Republic of Congo. Credit A. Plumptre/Wildlife Conservation Society Usage Restrictions One time usage only. Must use the following credit: A. Plumptre/Wildlife Conservation Society Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.