How about an awesome drawing video on how to sketch an animal. This is a video I found on Youtube by artist PaintBasket. It is a really good sketch of a squirrel and if you watch the drawing video you will see that it comes out looking pretty realistic. If you think about it, sketching and drawing realistic is essentially that same thing. The only difference is when you sketch, there is a less definition to the object, person, or animal that is being drawn. Nonetheless this is a great resource because it shows you how to sketch an animal. Have fun folks.