the thing about gorillas is that they're smart enough to understand they're being caged. you've seen at least one action movie, right? what happens when the aliens put an action hero in a cage, and the action hero gets the chance to escape? doesn't even need to be aliens, either, does it? could just be bad guys. and, it's carnage.

you consequently need to interpret the violent behaviour, when it happens, as a function of their captivity. you'd act no differently, yourself. it doesn't matter if the aliens or the bad guys "treat you well". you're still going to eat their faces if you get a way out.

but, it's different if you're integrated into the family. maybe there's a level of stockholm syndrome, but it's a different scenario than being locked in an enclosure.

what's going to define the nature of the beast is going to primarily be whether or not they interpret you as food. you're nuts to try and befriend a tiger. but gorillas are never going to interpret you that way.

of the other intelligent species? elephants aren't going to eat you, either.

cetaceans are sketchier.