Something that doesn’t necessarily embody fear but cautiousness.
Contextually, this could relate to social environments.
A desire to remain in tranquil environments.
A general preference of calm environments.
A desire to not be the center of attention.
In general I am seeking a word that could be used to describe a person/animal/thing.
I would suggest introverted:
Characterized by interest in or preoccupation with oneself or one’s own thoughts as opposed to others or the environment; shy or reserved.
At least in the US, people typically describe others who would rather be by themselves than with others as introverted.
Source: the free dictionary