baby monkey
Refers specifically to a young, infant monkey.
At the zoo, a baby monkey was clinging to its mother.
small monkey
Refers to a monkey of small size, not necessarily an infant. Can overlap with 'baby monkey' in casual use.
This kind of small monkey is so tiny it can fit in the palm of your hand.
General term for monkey; 子猿 specifically means a young or small monkey.
Alternate spelling of the same word; 小 emphasizes smallness, while 子 emphasizes youth.
Standard kanji spelling for 'baby monkey' or 'small monkey'.
Alternate kanji spelling; 小 emphasizes smallness.
Mixed katakana-kanji spelling, sometimes used for emphasis or in children's materials.
Rare spelling using 仔 (young animal).
Mixed kana-kanji spelling, common in informal writing.
Compound of 子 (こ, 'child') or 小 (こ, 'small') + 猿 (さる, 'monkey'). The reading こざる is a straightforward combination.