A leopard can't change its spots

tʃaɪniːzle̞tə tsɯᵝ tʃaɪniːzle̞tə no̞ tʃaɪniːzle̞tə tʃaɪniːzle̞tə mä te̞ dʒapəniːzle̞tə ɛm aɪ tiː tiː ɛs juːdʒiːəʊ ɛn əʊ tiː eɪ ɛm eɪ ɛs eɪtʃ aɪ aɪ eɪtʃ waɪ eɪ keɪ juː ɛm eɪ diː iː

In Japanese 三つ子の魂百まで (Mittsu-go no tamashii hyaku made)

This Japanese idiom, meaning 'The soul of a three-year-old lasts until 100,' implies that early character traits persist.