Anthropologists from the University of Colorado noticed that in some cultures, kids never crawl; they get carried for a year, then they sit, and just start walking. And that crawling might have only evolved in the last 200-300 years, thanks to wooden floors.
Which is fascinating, but mainly I'm posting this because Popular Science used the totally wrong baby crawling photo from Christopher Porter's flickr stream. It's fixed now.
Crawling: A New Evolutionary Trick? [popsci]
