Gorilla

The gorilla is a synthetic creature found in the Bioscience section of The Institute contained in terrariums.

Background
The gorillas are a pet project by Clayton Holdren in an attempt to recreate pre-war gorillas and hopefully other species. There are two specimens, and both are actually Synths designed in the form of the Silverback Gorilla. This is revealed upon talking to Clayton, who brings up the gorillas while introducing the Sole Survivor to Bioscience during Institutionalized.

Characteristics
The gorillas are largely passive to the player and wander around their terrarium. However, during A House Divided, their enclosure can be opened, where they will be hostile to everything, including the player. This same occurrence can happen if the quests; The Nuclear Option (Brotherhood of Steel), The Nuclear Option (Minutemen), and The Nuclear Option (Railroad) are carried out against the institute. Also, placing an Institute beacon during Airship Down may spawn a couple of them to your side. Upon breaking into the Bioscience division, the cage will then be opened and the gorillas will attempt to assist the synths in combating the Sole Survivor and whatever faction they chose to side with.

Biology
They are synthetic gorillas which are said to be very aggressive.

Appearances
Gorillas appear only in Fallout 4.