Does your ferret do something you don't understand? This website has a very detailed index on how to understand what your buddy is trying to tell you:
Domestic Ferret Behavior
lol, there is lots of "what he is thinking" in that link.
I just wonder how they come into the conclusions of what exactly the animals are thinking. We still misunderstood other humans' body languages or even human languages on many occasions haha...
I have to agree with Ram. How do they know what the ferret may be thinking. Is it a ferret whisperer. I think animals can communicate to use when they need or want something, by tugging or speaking for example. But thinking, I don't think so. I still can't seem to know what my kids are thinking much less than my pets.