Some animals don't seem to mind the confinement in a zoo. But the apes and monkeys seem to know what is going on. Their looks are sometimes like an accusation.
Macaques are smart animals. You can see it in their eyes.
And then there are the apes, bigger and far stronger than man.
To photograph them is probably annoying to them. They don't like to be looked in the eye. This gorilla once escaped his confinement to punish a women who stared him in the face. His popularity in the whole country is unmatched ever since.