In a tweet posted December 29, 2016, character animator Anatola Howard observed design similarities between three animation icons.
diagram i made depicting evolution pic.twitter.com/R77ya092Jv
— ANATOLA HOWARD (@MAROONRACOON) December 29, 2016
A publication timeline supports the pattern. Mickey Mouse (1928) predates Astro Boy (1951). Goku first appears in Weekly Shonen Jump Magazine on December 3, 1984.
For character designers, the similarity won’t surprise very much. The hair colour and shape stands out. The white negative space contrasts the positive space, which is the black hair and ears. The design echoes from Mickey Mouse to Astro Boy, to Goku.
For more art and insights from Howard, their tumblr has an art collection.