Characteristics
Catgirls typically display cat-like behaviors, exhibiting traits such as playfulness, mischievousness and deviousness. Sometimes this may include cat gestures or sounds in written or verbal communications. An often used running gag is that catgirls habitually end their lines of speech with the phrase (にゃあ?) nyā, the Japanese onomatopoeia for a cat's meow.
In anime and manga regular humans will sometimes sprout cat ears or a tail in order to illustrate their excitable or playful personalities. This is similar to the phenomenon of becoming chibi. Additionally characters may be portrayed with a catlike mouth to emphasize mischievous thoughts or comments by a character.
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