strange behaviour

Question
our Sibe is 14mo old and after her 2nd heat she started showing aggressive behavior towards certain dogs, especially small ones, the hair on her back will stand up and she will with much aggression barks at them and try to get to them, which we think might be because of her natural hunters instinct, but it does become a concern when we take her for a run/walk on the beach.  In the past she would charge any dog but turns when she gets to them an run on or back to us.  She is a only dog and we also have a cat which has so far never tried to attack, tried to play with, with no success only got a few quick left and rights from the cat but generally quite tender with it.  She has caught a mole, a few mice and fish.  She is a well behaved friendly playfull typical  Sibe and we love her to bits, Please help with some advise on how to handle the aggressiveness.

Answer
Unaltered dogs can become aggressive to other dogs if not socialized and raised properly as a young pup, and even then, it's still something that can happen.  My best piece of advice - get her fixed.  It will eliminate most of the aggression and makes things much easier to deal with.