A brief look inside the sketchbook
What usually happens with a new character, is that I draw the animal in question as realistically as possible, and then noodle around until I have a suitably abstracted version to fit in with how Bert gets drawn. The squirrel is a reasonably fair example of this, although he hopped from grey to red at the last minute during colouring in.
Since the squirrel only appeared once, I really only had to get to one view, which ended up being pretty rough and unfinished in the prep drawings. I'm lazy, I'm afraid. You get pretty much where you want to go and that'll do for now (top right, second pic)!
Prune is a bit more involved, so there will be a lot more development ahead. One of the things Prune has to do, and this will be crucial for the second book plot, is float. I had some fun because, whilst she can float very easily, she doesn't necessarily float the right way up on first attempt.
I also had some fun with the wake she might produce :-)
Bert doesn't float so well.
Real Bert actually takes a very dim view of water and avoids it like it's battery acid.