I have two indoor cats, age 7 and 9, and a new whippet pup, about 8 mos. old.
After two days, the cats avoid the dog, and hiss when it gets too close.
How will this situation likley turn out over time?
The cats and dog learn to love each other and sleep and play together.
The cats and dog learn to ignore each other.
The dog, a hunter, grows up and eats the cats for lunch one day.
After introducing not one, but two, german shepherd pups to my 7 yro cat, in my experience you’ll get #2.
Although I did think #3 flitted through the pups’ mind, especially when she decided to go on a nose-whacking, fur-a-flying, hissy, teeth-baring fit.
Now that the pups are 2yro and 105 and 115 pounds, it’s actually quite comical to watch grannie cat chase them around the house after they screw up the nerve to attempt to raid her food dish.
I don’t know if this applies directly, but I introduced an adult hound mix (we think she’s four) into our house with two overly-complacent older cats about seven months ago. What has happened is:
I’d bet on number 2, though it depends on the cats involved. I’ve lived in a couple cat/dog households and usually what ended up happening was that they left each other alone until one of the cats got pissed about somthing. When the cats got pissed the dog usually ended up with a couple scratches on the nose and a very solid idea that messing with the cat was a bad idea. Note, a very solid idea for a dog can last a long time, or until the pain goes away. Usually the second.
In one situation the 6 pound cat totally owned the two Chows. The Chows, who each outweighed the cat by like 70 pounds, knew who the boss and that the boss had claws. The cat would go where ever she wanted and the Chows would make sure not to get too close to the cat.
I had another situation where the cat never quite got used to the dogs and would vacate the room when they entered. The dogs did learn (the hard way) not to try and make friends with the cat. No fights ever happened, they just kept away from each other.
Slee
My Lab pup (this was 21 years ago) met the cat for the first time on like the 3rd day
we had him (the pup). The cat slowly walked up to the bewildered pup, eyed him
over carefully, and then slowly and deliberately raised his paw, extended his
claws, and calmly poked the pup in the nose. Pup went tearing down the hall,
yelping for his life. From that point forward the dog was simultaneously fearful of
and obsessed with the cat, would always look out the window trying to see where he
was, would go nuts if I said the word “kitty.” Later after the cat died my dog
encountered another cat, which was very large and would brook no nonsense from
any dog. When my dog started barking at it the cat hissed and charged. My poor
Lab went tearing off into the woods, yelping for his life. This cat never touched
him.
I never saw an animal (first cat) perform such a deliberate, premeditated action
quite like that, before or since.
My old matriarch cat was the queen of the household. With each new mastiff pup she met, usually from the comfort of her (actually my) chair, she would hiss and raise her paw, claws extended, but only used them once. The dogs learned to leave her alone, and as they grew up and mellowed out, they would even sleep together when she deigned to use their dogbeds.
Our new young kitty instigates playfights with our current mastiff, sometimes they’ll even play chase, though this gets a bit frantic towards the end. (She looks like she’s just taken a shower.)
My wife and I bought a cat about 3 years ago (@1.5 y.o. at the time). Sweet tomcat…very affectionate.
We bought a Border Collie mix about 1.5 years ago…puppy. At the time of introduction, my wife was all “doom-n-gloom” about the interactions and the way she figured they’d go.
The puppy LOVES the cat. When we crated the puppy, the cat would sleep on top of the crate. When the puppy gets let out of the crate, it hangs around the cat.
Recently, the dog/puppy has started to herd the cat where he wants it to be. the cat takes this pretty well, surprisingly. Newton (the dog) will push the cat around with his nose, and Scotch (the cat) will go where Newton wants him to go.
Funny…my friends crack up.
-Cem
I think sleestak has it right: it depends on the cats involved.
Not quite the same situation, but when I adopted Bastian, my oldest cat, I brought her into a house with a roommate, who then brought in an 8 year old Rottweiler female. My cat stayed in a corner all day, hissing and futting and yowling and hissing some more, hair on end, tail poofy, on her tippytoes. The Rottie tried desperately to make friends, and would bring her tennis ball and drop in front of screeching Bastian, keeping a safe distance away, then nudging the ball towards her. No change. Hiss. Ffft. Hiss. REOW. Hiss. Roxie (the dog) would pick up the tennis ball, toss it in the air, catch it, then bring it bacl to Bastian again, as if to say See? It’s fun! Now you try! Hiss. Ffft. Hiss. ROWER. Hiss. Poof. Hiss. Hiss.
Eventually, Bastian would hang out in my room, waiting for me to close the door. She would then bat her toy mice under the door, and wait patiently for Roxie to hurl them back. This would go on until Bastian got tired or until Roxie ate all of her mice.
She would slip out and eat Roxie’s food sometimes, and Roxie would charge at her - not in an angry way, it was almost playful - though she obviously had no intentions of hurting the cat, she certainly didn’t want her eating her food.
After a couple of weeks, Bastian stopped hissing. However, she would still run, and never really got used to the big, playful lug who just wanted to be buddies. Then I packed up Bastian and we moved to Seattle. She was the reigning Queen of the household and she liked it.
Then we adopted Kero, another female cat a few months younger than Bastian. Bastian hissed at Kero for two weeks. Kero didn’t care. Long story short, they’re buddies now. They’re both about three years old.
We’re hoping to introduce an Australian Sheepdog into the mix sometime soon. I wonder how that will go…
It all depends on the personalities of all involved. Good luck. Hopefully the hissing will stop in a couple of weeks.
From Whippet Rescue FAQ.
Bolding mine.
Oh, come on. My Pookie would never hurt my Yum-Yums. They just don’t know how sweet my Pookie is. "All whippets are evil cat-eating monsters! Sheesh!
j/k. thanks for the info. 
No prob. I am a catfella myself, but I have been overrun by 2 1/2 Jack Russells. There are a few horror stories on the JRT website that convinced me that cats are not an option. Some folks have come home to find that the cats who shared a bed with their JRTs for years have been killed.
I do not mean to paint a gloomy picture. Forewarned is forearmed, however.