My King Charles does not like other Dogs.

Question
I have a two year old male king charles. he is very placid and is very loving,he has never snapped or tried to bite anyone,he is a very good dog with people, but when it comes to other dogs,he gets very uneasy around them, starts growling and barking.  When his is brought for walks he tries his best to get at other dogs and sometimes barks.  My sister recently got a cocker spaniel puppy and when she brings him to my house my dog goes mad barking and growling,we have to hold him back from the puppy.  Now we just keep them in seperate rooms as it is easier. can you tell me why my dog behaves like this and is there anything i can do?

Answer
Dogs need to be socialized when they're young!
The reason being, well, exactly what you're experiencing.

Puppies are just adjusting to their world. Learning not to bite people, not to leave presents on the rug, not to chew up shoes---and the reason you can teach them this, is because their minds are young, fresh, and unmolded.

Can a 2 year old dog be socialized? Maybe. But it will take a lot of work!
You should find crates for both dogs, a reliable trainer, and some books on how to succesfully socialize your pup!

When they have "playtime", it's best to choose a neutral area to both of them...if you bring a foreign male dog into your house, your dog is probably going to see him as a threat...but if they walk up to one another in a random dog park someplace, there will be less teritorial tension.

Also, having your dog neutered may cut down on some dominance aggression. It's not a fix-all, but there's usually some improvement.

Using treats is usually a no-no, because it will cause "mine! mine! mine!" behavior. But feel it out. If it works for you...great. :)

Then, also keep in mind, some dogs just don't prefer the company of other canines. Unfortunately that's not abnormal, and if your dog refuses to warm up, the best (and safest) thing you can do is keep them separated.

PS - Does your sisters' cocker spaniel leave "happy trails"? I had a male cocker spaniel once, but soon realized the true meaning of happy trails. When this particular breed gets excited or nervous, they generally dribble! No, they won't leave a puddle of urine on your floor...but they might leave trails of urine as they run to meet you at the door! I've always been curious if there are cocker spaniels who DON'T leave happy trails, or if they all do...
Anyway, if your sister experiences problems like I did, you should check out "belly bands" for male dogs. They're a comfortable, mainly cotton strap that goes around your dogs waist and traps dribble. Did wonders for me :)