Advice needed...Aggression, PLEASE!

First off, I did read the aggression thread and it gave some really good info. I saw some things I was doing wrong! But I wanted to get some input on my specific situation. After reading the list I think Thunder has Fear Aggression. The situation is this: Thunder is a 3 yo Siberian. His aggression is toward our 80 lb Labrador. This has happened about 5 times, with last night being by far the worst attack. Usually it is triggered by Raven (dog) barking or growling at something outside (one a rabbit, sometimes people, last night another cat). When this happens, he lets out a growl/scream and attacks her, biting and scratching. This does not stop until we spray him with water (which is what I read we may be doing wrong). Without the spray, my husband and I try to intervene and he just either scratches or bites us to get back to the dog. She never fights back, just stands there...last night she cried everytime he hit her. It was so sad.

Usually after a few hours, there is still some tension but not a huge deal. This time, he will not leave her alone, she can't move without him attempting attack her again. While she slept, he sat right in front of her and watched her (until I took her into another room) even with the door shut, he sat outside and watched under the crack in the door. I am so scared. I figured it would be ok this morning but it isn't. The one thing different that I thought of, this time, we have the kitten. He wasn't even in the room at the time, but was Thunder trying to protect him? It is just weird that he won't leave it go this time.

I want to add, they love each other any other time. Sleep on the same bed, even "wrestle" each other sometimes. Thunder will sometimes lick her face if she is sleeping or rub up against her. I am at a loss. I am so frustrated and stressed out. Its been over 6 months since this happened. Please help me, any advice, suggestions welcome. Let me know if you need more info.

I agree. It sounds to me that your cat is afraid of your dog. I have a similar situation but my dog tends to be aggressive so I keep the cats and dog separated when I'm not around to supervise. Also, I think it's fair to say that my cat is a touch aggressive herself.

Because of the tension we sometimes have I do not allow our dog to bark at the cats or to try to play with them when they're all out together. While my two males wouldn't mind it would upset the female who's afraid of the dog and I don't really expect the dog to draw distinctions between the three (though she's smart enough.)

I wonder if you try finding a really cool treat that your cat could get only when she's near your dog. I'd, of course, have the dog lie down and be still and calm and then ignore the dog and feed the cat some tuna or a couple pieces of chicken near-by. I'd really try to find a way to get them near one another in a calm and controlled environment and think about it as teaching your cat that there's nothing to fear from the dog.

Hrm, well if the cat only attacks the dog when the dog is barking, then I don't think the cat is so much afraid of the dog itself, but of the possibly 'aggressive' note in the dog's tone when it begins to bark.

How often does your dog bark? Is it a very loud bark that sounds menacing? That could very well be the trigger, since many animals respond emotionally to tone of voice. You may have to work with the dog as well as the cat, to try to teach him to either bark on command or silence himself after the first bark, so not to startle the cat into an attack.

As for the cat, if you can find a sound sample of a dog barking that is similiar to yours, seperate your dog from kitty, and play the sound sample just to see how kitty reacts.

It very well could also be, that if Thunder feels protective of the kitten, the 'aggression' in the dog's barking could set off that paternal instinct to protect by fighting.

Thanks for the replies so far. Keep them coming. I know Thunder isn't afraid of her on a daily basis they usually like each other. We noticed that the alert bark is sometimes a deep bark which may be the trigger. However, I should say one time over a year ago, I accidentally stepped on him and he attacked Raven. She was just laying on the floor. I am at a loss. I think I will get some of that Feliway plug ins after work but I'll be honest, I don't even want to go home. I can't get the picture out of my head of this attack. Now don't get me wrong, I am not showing him that I am uneasy. I wish we could go back to normal!