I'll offer my perspective as a Native Indian who walks with her animal guides daily....
So, um, I will say that they do exist :)
And they can be 'permanent', inasmuch as anything is permanent, especially when the animal is a power animal, clan totem, or band (or ancestral) totem.
Not all Native Indians believe in the 9-11 totems philosophy. Actually, many don't.
For myself and my band, we differentiate between a 'guide', which for me can shapeshift into many forms, and a Totem, which stays as it is.
My Power animal has been with me for many decades.
My Clan totem even longer.
Totems do not have to be animals, either. I know people with cloud totems, rock totems, and totems of the Green and Standing People.
What needs to guide you will speak to your heart....and until you know your real animal guide intimately, you can just let your heart be your guide.
*~Best~*