Of the two gorilla species, the Eastern Gorilla has the largest subspecies. The Eastern Lowland Gorilla, also known as the Grauer's Gorilla, is the largest subspecies of gorilla, with adult males weighing up to 400 pounds and standing over 5 feet tall on two legs.  The Mountain Gorilla, a subspecies of the Eastern Gorilla, is slightly smaller but still one of the largest primates on the planet.