Certain parts of the story had moved her and seemed to contain a germ of truth.
She […] placed her forefinger on her mouth with an air of entreaty. She was counseling me not to show myself in my true colors to Zaius. I obeyed her without understanding the reason for these mysteries and, convinced that I had an ally in her, promptly resumed my intelligent animal attitude.
I lost my head and once again behaved like a madman. As a matter of fact, I was literally mad with rage. I screamed and yelled like the men of Soror, showing my fury as they did by hurling myself against the bars, biting them, foaming at the mouth, grinding my teeth, behaving in short in a thoroughly bestial fashion.
It seemed absolutely clear that industry did not require the presence of a rational being to maintain itself. Basically, industry consisted of manual laborers, always performing the selfsame tasks, who could easily be replaced by apes; and, at a higher level, of executives whose function was to draft certain reports and pronounce certain words under given circumstances.
Meanwhile the apes are meditating in silence. Their brain is developing in solitary reflection … and they are talking
Pierre Boulle, Planet of the Apes