I am guessing that it is Google that introduced the idea of changing their site's presentation according to various events (I can be wrong of course). Today, Father's Day (if it weren't for search engines I wouldn't know this kind of thing) is no exception and I just noticed something funny.
It seems like DuckDuckGo and Google have the same idea of a modern day father, it is someone who wears a tie, preferably brown/yellow. They are both retro 60'sish as well. Mad Men, is that you ?
Meanwhile, at Bing, things are very different. For Microsoft's search engine the paternal image is represented by...... ... a penguin !