Gorilla

The gorilla is a synthetic creature found in the BioScience division of the Institute contained in terrariums $$ With the Wasteland Workshop add-on, they can be captured in cages and domesticated in settlements owned by the Sole Survivor.

Background
The gorillas are a pet project by Clayton Holdren, whose goal is to recreate pre-War gorillas and hopefully other species. There are two specimens, and both are synths. This is revealed upon talking to Clayton, who brings up the gorillas while introducing the Sole Survivor to BioScience during Institutionalized.

The Sole Survivor can read in the division's terminals that the gorillas react aggressively to perceived conflict, which may be a fault in their behavioral model. Ghoulrillas are ghoulified varaints living in Nuka-World.

Gameplay
The gorillas ignore the player character and wander around their terrarium. During A House Divided, their enclosure can be opened, where they will be hostile to everything, including the player character. This can also happen if the The Nuclear Option quests are carried out against the Institute. Also, placing an Institute beacon during Airship Down may spawn a couple of them to the player character's 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.

Gorilla
The basic variant of the gorilla are made by the Institute and are the weakest variant in the game. With the Wasteland Workshop add-on, gorillas can be captured with cages and used for settlement defense.

Appearances
Gorillas appear in Fallout 4 and its add-on Nuka-World.