hiya,

Charlie is a lovely dog who has always got on really well with other dogs, he has been well socialised from a young age. However recently he has become quite aggressive towards other dogs especially if they are younger than him, he is 21months. With most dogs he is fine (they are generally older than him).
He generally gets moody when he is playing with a toy, however I have realised this and started taking the toy away if there are other dogs around. but this doesn't work either, yesterday he met a young dog (a year) who was much bigger than Charlie. when they first met they were fine but when they came nearer to me and possibly where Charlie thought the ball was Charlie went for him! Neither dog was on a lead.
Other than his sudden attacks on certain dogs he is a very well behaved Terrier who loves to watch the TV. I think he has just got too big for his boots and has developed a very large ego!
If anyone has any advice as to how I can stop him being aggressive and teach him to control his temper! I would greatly appreciate it.

many thanks,

anna

Hi Anna,  It is always difficult to advise on aggression without seeing the dog unless there is a very specific and obvious reason.

If you think it's because he is too big for his boots and has a large ego then maybe you should consider neutering him.  Some entire males can give the impression that they 'own the place'  to other males which may lead to misunderstandings.

The only other thing that it seems it could be, from your post, is him not wanting another dog to get his toy or come near you.  You are right to put the toy away when another dog appears.  I would probably let him continue to greet dogs, as you say he is usually sociable but maybe just for a short while and then call him away and wait until you are on your own again before getting the toy out and playing with him.
You have to be very observant and learn to read the body language of your dog and others and try to avoid potential 'hot spots'.  In my experience the best way to diffuse a possible spat between two dogs is for the owners to calmly walk off in opposite directions.
Best way to teach him to control his temper is to avoid letting him practice losing it.
HTH
Sally