See no evil, scream no evil, hear no evil. An extension of Edvard Munch's Scream.
The three wise monkeys are a pictorial maxim. Together they embody the proverbial principle to "see no evil, hear no evil, speak no evil". The three monkeys are Mizaru, covering his eyes, who sees no evil; Kikazaru, covering his ears, who hears no evil; and Iwazaru, covering his mouth, who speaks no evil.
Sometimes there is a fourth monkey depicted with the three others; the last one, Shizaru, symbolizes the principle of "do no evil". He may be covering his abdomen or crotch, or by crossing his arms.