What is an "eastern lowland gorilla"?

The eastern lowland gorilla, or Grauer's gorilla, is the largest of the four gorilla subspecies, with males weighing up to 400 pounds. They have dark black fur, a broad chest, and a sagittal crest on their forehead. Eastern lowland gorillas live in dense forests and are primarily herbivorous, feeding on leaves, stems, fruit, and flowers. They live in social groups led by a dominant silverback male, and have complex communication and social behaviors. Unfortunately, they are critically endangered due to habitat loss, poaching, and civil unrest in their native range, and conservation efforts are underway to protect them and their declining populations.