Being able to draw a good crocodile is a useful skill than any self-respecting child should have! Here's a clever way to learn.
Learn to Draw a Crocodile
The Echidna is a bit like a cross between an ant-eater and a hedgehog and lives in Australia. You can learn to draw one with this worksheet.
If the kids like sharks, why not help them learn how to draw their own shark with this step by step instruction sheet?