Well, Steph, he will have to be at least 2 before he is really an adult dog, and only adult animals usually have all it takes to be a "out in public companion dog".... Dogs used to be considered 'adult' at 12 months, after a couple of months of sexual maturity and having gained their full height... However, it is now recognized that they are really still kids, teenagers at best.

But in the meantime, he is trainable from DAY ONE. We got a Westie many years ago, about 8 or 9 weeks old. The next day we went to Kentucky fried chicken and took our dinners to a picnic table in the park. Of course the pup was interested in what was to eat, but I gave the sit command, helped him into the sit position, kept complimenting him as we ate that it was a GOOOOOD sit. I don't recall if we waited til we were completely finished or not (but it was chilly and not a day to linger), but then I again praised, using the GOOOOOOD SIT again, then ruffled his head, patted him and let him rise and come forward --- and rewarded him with the small pieces of chicken I had accumulated for him.

He had SIT down permanently from that day forward, rewarded with only a pat or bragging. Puppies, from the time they start biting, from when they begin playing with their littermates, they are being TAUGHT, TRAINED every day.

If your puppy nips you (or kitten bites you), you give a high pitched little wail of distress. The puppy or kitten will stop immediately and study you. The next time he/she wants to play, any nip will not be as firm. With repeated signals, they can be trained, without any punishment or reward at all because this is all instinctual learning.

I would watch the Animal Channel and watch "It's Me or the Dog". It is an excellent training program on how to keep bad behaviors from beginning (even tho she comes in when things have gone to hopelessly out-of-control). If they program is no longer on, check with your library to see if they have it on tape or dvd to check out.

Chihuahuas are notoriously bad in becoming this type of dog, but it is not their innate nature, it is Learned Behavior. What is inherited, innate, is the fearful trembling nervous nellie dog who is prone to fear-biting. Dog aggression is inherited.

Territoriality (guarding his home) is inherited. But a dog can come to see YOU as "his" property, becoming a threatening menace to those who approach too closely and who are friendly to you. But choosing WHAT to guard and how ferociously guarding IS trainable. A dog's job (and every dog DOES need a job, even if patrolling the baseboard for roaches) is so very important to his emotional stability, but with a Chihuahua you need to be very vigilant in his training and select an appropriate job for him.

Because of a Chihuahua's inborn traits, he wants to and WILL become the alpha dog of your household and run the household, OWN you and BOSS you for the rest of your life unless you are aware of the dynamics and learn how to assert yourself to be the alpha dog in your home. Don't worry, you won't break his spirit and he WILL be a happier more secure dog if he thinks he can depend on YOU to take care of things, take care of him.

There should be some good material online about the niceties and finesse in dealing with Chihuahua training so they don't end up training you. With any dog, the human MUST be the alpha animal in the household. It makes for a happy secure dog - and a happy secure dog wants to behave to please you...

AND if you go to visit someone or have them come to visit you, it will always be a pleasant experience, not a situation where someone gets bit or otherwise ends up thinking you are a jerk for letting your dog treat others that way... But he was your baby and a wonderful companion and you forgave him for his excesses. But this time, you have a chance to change the outcome.

Hugs - I adore friendly relaxed Chihuahuas... I never go around trying to become friends with dogs on first meeting, just "acquaintances" (well, Labs don't count since they who refuse to let you even consider staying a stranger! ), but if a dog is relaxed around company and newcomers, then the visit is a success and the dog a winner.