Well, according to Christian Alzmann, Art Director at Industrial Light and Magic, the gophers were Spielberg's idea. Check out this interview: http://uk.dvd.ign.com/articles/925/925408p1.html
Excerpt:
IGN AU: We have to ask – who's idea was the CG hedgehog?
Christian Alzman: Oh! That was a Steven thing – just to bring in a little levity. Just when things get too serious – as Indy movies go – they throw in a laugh to relieve some tension.
So, there you go.
Excerpt:
IGN AU: We have to ask – who's idea was the CG hedgehog?
Christian Alzman: Oh! That was a Steven thing – just to bring in a little levity. Just when things get too serious – as Indy movies go – they throw in a laugh to relieve some tension.
So, there you go.