Hi all, and @mulberry,
I’ve had odd experiences with attempting Core Shamanisms first exercise.
I would journey in my mind to the old oak tree in our backyard, and find the tunnel to fall down into.
There is a creek or small river. An animal scurries by. That there is the question.
Other animals seem include a snake, a deer, and a small bird.
What is the unseen animal and which is the Spirit animal to engage with?
I would say, none at this time. The spirit animal hasn’t revealed itself, and you’ll intuitively know when it does. If you’re not sure, than that’s the sign that none of them are right, and more work is needed until the right one shows up.
Personally, I don’t have a spirit animal (jokes in my profile bio aside). 
I think I thought it was a deer once, but nothing came of it. I think it’s ok to just work with the human primate we are all incarnate into.
Perfect advice. Thank you! I will keep trying and note the changes.