[Elswick]

At around 2 years of age the rottie becomes more territorial. It is not uncommon to see them become more protective. Saying that, it is very important to establish Pack Leader status with your dog. If a dog senses you are not the Pack Leader then they will take over that role and decide how to protect the property and his family. Dogs can sense energy and they sense when the owner is nervous, worried etc. They also sense when the owner is not the Pack Leader and dogs are a social animal and require the heirarchy structure in their lives. There is no democracy with dogs. You should check out Cesar Milan's methods. Just google his name. Here are some pack leader behaviours: Pack Leader sleeps in bed and dogs sleep on the floor
Pack Leader sits on couch and dogs sit on the floor
Pack Leader eats first and dogs eat after Pack Leader is finished
Pack Leader walks through doorway first and dog follows second - with permission
Pack Leader can take dog's food or bones away at any time
Pack Leader is able to scratch dog's belly anytime he or she wants to
Pack Leader provides dog with lots of exercise
Pack Leader has dog release toys from mouth on command
Pack Leader establish no go areas in the home
Pack Leader will use body language, facial expressions and voice to establish dominance
Hope this helps. As pack leader it is you who decides what behaviour is acceptable.