The strongest won't survive. The fittest will. At least according to Darwin. Survival is a prize granted to those who fit best into the specific balance of a given environment, who have this particular set of characteristics, which sometimes are even invisible to human eye. Sometimes it's the speed. Sometimes it's the colour of the feathers. Sometimes it's the position of the thumb. Sometimes it's the amount of down on the fruit that protects it from parasites. But the environmental balance isn't settled once and for all. With climate change, quality and quantity of food, the number of representatives of given species or the taste of the audience, the favoured characteristics do change and individuals equipped with them start to have bigger chances for replication and gaining goods, which are always limited. And that's why we evolve. To adjust. And that's why Mickey Mouse evolves. To adjust. To us.
He is 62 years old. He had to fight for our attention with Felix the Cat, Popeye The Sailor, Bugs Bunny and plenty of others. And he survived. He changed a lot from the beginning, but he survived. His microenvironment helped. For example Felix the Cat didn't succeed because his microenvironment was silent (side note: the first words said by Mickey were „Hot dogs! Hot dogs!”). Innovative and skillful use of technicolor also helped our Mouse to establish his position.
He also had good lawyers. When together with his rival – Bugs Bunny they starred in „Who framed Roger Rabbit”, it was settled, that the length of their appearance was to be exactly the same to a microsecond. But all of that wouldn't have been enough. He himself also had to change. His head got larger. Just as his eyes. His jaw retracted. His tail disappeared and generally he got kind of rounded up. And he's not so rugged anymore. And he doesn't fight for a girl like working class heroes. He got boringly polite which actually goes much better with his falsetto (another side note: at first Walt Disney himself gave voice to Mickey but then all the cigarettes he smoked made him rather growl than speak). As Stephen Jay Gould wrote in his article ”A biological homage to Mickey Mouse”, Mickey more and more resembles a child. He's getting younger. He's evolving backwards.
According to Konrad Lorenz, that's how our perception of animals works. We see human traits in them. We tend to judge their mimics and behavior the same way we judge ours. So, when Mickey looks like a child, subconsciously we treat him like a child, and children are sweet and charming. Maybe that's the pattern that Disney's illustrators followed. Maybe even without being aware of these processes they tried to make Mickey look sweeter and more charming. If that is so, than we already have a part of this history. We know how and why he changed. But a much more interesting question still remains unanswered. How did we change? Because he's adjusting to us, isn't he? So, is it that now he is simply better adjusted and we are the same or maybe in the last 62 years something has also changed in us (or in the way we want to be perceived)? And if so, why do we want rugged men to grow into charming children? Why don't we want him to fight anymore? And why does Mickey have to wear those gloves all the time?"