When Hubs and I moved in together, we created a blended family. I had two cats, Alex and Stella, and he had two dogs. Two BIG dogs. The cats had never been around dogs, and vice versa. We knew it was gonna be interesting.
We tried a test run before I actually moved in. I took Stella, the younger and friendlier kitteh, over to Hubs' house to see how everyone would react. I carried her in the house, she got one whiff of DOG and ran straight under the bed. That's where she stayed for the next 24 hours. Every time I went by the bedroom I would see the dogs huddled with their heads under the bedskirt, tails wagging furiously, and I would hear Stella making that weird rraawwrrrrr cat growl that means she is REALLY, REALLY pissed.
Finally I took pity, extricated the oh-so-miserable Stella from the dust bunnies under the bed and took her back to my condo.
Undeterred, I moved in a few weeks later. Now BOTH cats were living under the bed making that rraawwrrrrr noise while the dogs sniffed happily around the edges. I did a little research and found that a good way of acclimating animals to one another was to let them interact through a closed door. Therefore I created a cat home in the office - they had their litter box, their food and water, their scratching post and toys. The carpet at the door just outside the office quickly became discolored and dirty from the dogs parking themselves there.
A few days into this, I decided it was time for the dogs and cats to REALLY get to know each other and start getting along together. *snort* This is hilarious. You see, the cats RAN whenever they saw the dogs, and the dogs, being dogs, CHASED. It's instinct. The dogs would chase the cats into the office. The cats would jump onto the sofa. The dogs would bark frantically. The cats, in pure self-defense mode, would start swatting. One or both dogs would end up bleeding.
I can't tell you how many times I heard horrendous battle sounds from the back of the house and then saw one of the dogs casually stroll into the living room, bleeding from scratches on its nose, and look at me like "What?? I wasn't doing anything!"
One day the dogs ran the cats into the office and the horrific sounds of carnage ensued. The hissing, the barking, the yelping...
Moments later, Jake, our English Bulldog, came sauntering back into the living room and I took a quick look to make sure his nose was still attached to his face. Thankfully, it was. I did note that he seemed to have a bit of fuzz on his face. Eh, just doggy mess.
A few minutes later Jake plopped himself at my feet and I saw the bit of fuzz again. "What IS that, Jake?"
I grabbed his face and plucked at the fuzz. It was a cat claw. Embedded in his nose.