i have a dog (chihuahua) that will growl and snap when other dogs go near him. after a while of being around the other dogs hes fine and wont do it. but im afraid for him cuz he does it to big dogs sometimes and all it takes is one bite from a big dog and hes gone. is there a way to get him to stop doing that or is it just a Chihuahua thing that cant be stopped? hes gotten better as hes gotten older. hes a year old. and hes only aggresive to sertaint dogs, not all. ive been working with him since ive gotten him. will he aventuly get better?