Boxer becoming aggressive

Question
Hi,
My 20 month old male boxer has become aggressive when anyone we don't know comes to the door or else when we are in the truck and talking to a stranger with the windows down.  Even though the person outside the truck wants to pet him, he growls and its not a nice thing.  He is a social butterfly when we're outside around a big group of people and loves all the attention.  Why is he so protective or aggressive when we're in the truck or at home?  Thanks so much, Nancy

Answer
Boxers are very protective of their families and homes.

When a stranger or anyone, knocks at the door- they are "intruding" and threatening to their family and home.

When outside the home- yet inside the vehicle, it is still the Boxer's domain and "home" on wheels- with family, and he will continue to guard and protect. He views it as threatening.

In a social environment, you are playing with other friends and family and have given your okay and approval. The Boxer views this as an extended family.

To help modify his behavior, lets start with the front door.

Buy a whistle or clicker- and each time he growls and barks at the front door- blow the whistle or click the clicker and verbally reprimand him.

Use easy-to-understand commands, a low and calm voice (no shouting, no yelling, no aggravation, no cursing, no threatening, etc.) but in a stern and reprimanding voice tone- and command him to go to a designated place.

Designate another room and spot where he is to go lay down at.

If you cannot teach him this, then leash him immediately following the whistle or clicker and verbal reprimand.

Continue this every time- and maybe practice it daily if possible. Have another family member or neighbor or friend knock at the door, or ring the doorbell- and practice the reprimand.

It is up to you to change his reaction to the door- and to modify his reaction. This will allow him to recognize that you are in command and that the doorbell or knock is not threatening.

When in the car or truck- use the same technique with the whistle or clicker- and reprimand him to stop.

Whatever command you choose to use- be consistent with it. Possibly get him to lie down in the seat and discontinue the aggression. No barking, no growling. Do not allow him to even do a low growl under his breath- it is still aggression and he is still winning the ordeal.

Continue with the whistle or clicker and verbal reprimand with any aggressive or unwanted behavior.

Let me know in a few weeks how it has improved.

Good luck :)