I got the chance to try some of the animals out for my niece's birthday. A tip for anyone attempting to sew fun things out of socks.....use your zig zag stitch. If you don't, your machine won't feed the socks through and you will end up sewing a huge knot. If you don't want to deal with the sock material, I think any of these designs would work just fine using regular fabric.
Here's what I made. They didn't turn out as cute as in the book, but they were my first try.
I added faces to them using puff paint. My nephew thought it felt gross, haha.
The kids liked them! Even the baby enjoyed chewing on the turtle.