Why do squirrels run up a tree in circles?

Why not just run straight up the tree?Why do squirrels run up a tree in circles?
imagine a population of squirrels - some geneticaly programed to run up straight and others in circles. imagine that their main predator is bigger and heavier than they are. The predator can ascend very fast into a tree in a straight line up but has real difficulty changing direction - ie going round and round the tree. Now, which type of squirrel will survive best to parent the next generation of squirrels? and what genetic makeup of running type will eventually take over the whole squirel genepool? you got it.Why do squirrels run up a tree in circles?
it might have something in common with a fact that when they spiral the tree, they quickly hide from you. You being considered a predator have to predict the squirrel's intentions, at it can jump onto the nearby tree, while you are waiting for its next spin to reveal again to your hungry senses.





-they sometimes stop at the opposite side of the tree trunk and lean up to see what are your reactions. if the squirrel stopped at the side of the trunk facing the predator, and turned head around, what are predator's intentions, it would be a very dead squirrel soon.
maybe they loved it that way