Cuckoo cries blood and calls the zodiac a monkey, because the cuckoo cries blood and the ape whimpers in the poem, and an ape refers to a monkey. Cuckoo cries for blood, an idiom in China, which means that it is said that cuckoo mourns day and night until the blood comes out. Often used to describe extreme sadness. From Don Bai Juyi's Pipa Trip.
Analysis of monkey species: monkey is a general term. Many animals in primates are called monkeys. Primates are 1 order mammals, the highest group in the animal kingdom, with developed brains; The track faces forward and the track spacing is narrow; The toes (fingers) of hands and feet are separated, and the thumb is flexible, and most of them can hold hands with other toes (fingers). It is also one of the twelve zodiac animals in China.