dog is starting to growl more frequently?

Is he a full male (A male dog that has not been neutered)? That would explain a ton. You need to be the one who is calm and kind, but let it know that you are the leader, not him. Also, how long ago did you get the other dog? Your dog might simply be jealous. Also, healthy dogs should not growl unless threatened or happy, so bring it to a vet, and the whole time, give him lots of love to ley it know you care :) Hope I helped!

Whenever aggression starts, it tends to get worse over time, unless you take steps to stop it right now. Being heavy-handed is not the answer, either. I would enroll this pup in a GOOD puppy class and start training him to sit, stay, come, heel, etc. At 4 months, you still have time to work with his little personality to change things. Food aggression is something to work on with a trainer (your puppy class trainer can most likely help you with this.) There are many methods of working with dogs. Some people tend to be more harsh than others. I would call the vet's office and ask for a recommendation of a good trainer.

If any of this is related to hormones, your vet may go ahead and neuter him a little early. We do this when a dog is beginning to hump or mark territory early. speak to your vet about this.

This could be part of your dog's basic makeup, or it could be the result of his being a bit spoiled, or both. You have a very smart dog that can try to manipulate you and the other dog. The worry is that your dog can cause the other dog to begin fighting back. Both need obedience training, with the help of a great trainer and then you must follow through at home for it to stick.

www.drsophiayin.com (good online source. She's a behaviorist and a vet.)

www.indoorpet.osu.edu (general site containing great puppy training information put out by Ohio State University.

If you're having problems at 4 months I would HIGHLY recommend you get yourself a professional trainer to come in home and work with you. This behavior is only going to get worse if you don't correct and deal with it now.

I would also recommend a vet visit to make sure this isn't a health related issue. I'm not going to lecture you but because you have a mixed breed "designer" dog you don't know the temperament of his parents. When people start intentionally mixing dogs they create unstable monsters. Just be aware of the issues, temperament and behavioral wise, that you could see in your dog. Like I said, I would hire a good trainer to help you.

show him who is boss be the calm assertive pack leader. Ceaser milan all the way!

Have him PTS.