He was sage-like in Escape From the Planet of the Apes
I can see him making a convincing apeman.
He didn’t enjoy the experience though...
It is true, however, that Mineo hated the role and took it purely for the money. He was embarrassed that an actor of his calibre was unrecognizable beneath monkey makeup, and suffered severe panic attacks brought on by the claustrophobic ape prosthetic appliances.