Kottke links to this wonderful homage to Mickey Mouse by noted biologist Stephen Jay Gould.
Over the years, Mickey has become more well-behaved and his appearance more juvenile (larger eyes, short pudgy legs, relatively large head, short snout, etc.). "When we see a living creature with babyish features, we feel an automatic surge of disarming tenderness."
I’m pretty sure I’ve read this before, but still find it fascinating. (via Kottke)