My brother owns a cat (unknown breed), and my parents have a dog (Black Lab/Golden Retriever), and they've lived under the same roof for about two years. However, recently Lucy (the dog) has been unnecessarily aggressive towards Rio (the cat), snapping at her, growling, and in some cases chasing her for a short distance. The problem has been getting worse, despite the fact that we keep punishing the dog every time we catch her doing this. Just recently Lucy cornered Rio and started attacking her, actually drawing blood. We've since locked her in her crate and aren't planning on letting her out again tonight, but Rio is holed up in my brother's room, and he's both pissed off at the dog and demanding that we get rid of her, and terrified that one day he'd come home to find that Lucy had killed his cat.

So, any advice? Or are we going to have to segregate both animals until my brother moves out in a year or two to go to college? Lucy is about five years old, is spayed, and has been to obedience school. Lucy was here first, although there weren't any problems when we first introduced Rio. Lucy did have a mildly traumatic experience with a cat when she was a puppy, when she got too close to a cat and got clawed across the snout, but that was years ago.

Are these just random encounters (you hear the dog growling at the cat in another room with no one present), or are there other factors? Does the dog snap at the cat when they are around certain people (Mom is in the room, dog at her feet, and the cat gets too close)? Is Lucy munching on a treat or playing with the toy, and Rio snoops a bit too closely?

How much exercise does Lucy get daily? How well trained/behaved is she (obedience school does not make a well-behaved dog)? Does she have any guarding issues (treats, food, toys)? Have you ever encouraged Lucy to chase after Rio before this problem arose? (My dog knows the phrase "get that cat" - though it only applied to the cat that loved to be chased by him - and it was hysterical to watch them)

You're going to have to reinforce (or actually train, if not done so before) that the cat is off limits. Waiting until the dog growls or attacks to discipline doesn't always help. Watch Lucy when Rio comes into the room. The moment Lucy looks at Rio with interest, or tenses up, get her attention. A firm touch on the shoulder with a stern "no" to break her look. If she turns to the cat again, get between them, using your legs to move Lucy away from the cat. If she backs up, and looks at you, praise her like there's no tomorrow. Throw her a toy in the opposite direction, have some treats in your pocket ready to reinforce her actions (if you've done clicker training with her before, it could be used here, too). Everyone has to be on board with this; and everyone has to help, your brother included. The key is to catch her in the moments before anything actually happens, BEFORE she gets excited enough to make a move towards the cat. You can't wait to see if this is the time that Lucy will get close to Rio and nothing happens. You need to be consistent and firm. The goal of this is to keep her from ever getting to the excited phase where she needs to go after Rio.

It's tough to say why this is happening suddenly without meeting the pooch in person, and truthfully could be happening for any number of reasons.

FYI, I'm a "hobbyist dog trainer". Nothing professional, but I've helped many friends and family train dogs, and have helped with behavioral issues. My own dog is an (now elderly) Aussie mix with pretty strong prey and herding drives. I had two cats when I got him, one of which was terrified by him. It took time, but Bogie learned that chasing cats in general was a no-no, and knows that if a cat looks at him funny, it is time to back off.

Thanks for the advice, and to answer your other questions, to my knowledge there's always been someone in the room when Lucy growls at Rio, although I will admit that I've been away at college for most of the year, so my own knowledge is incomplete. There's also no evidence that Lucy and Rio get into fights when all of us are away from the house. (although we're all fairly sure that both animals just curl up on separate couches and go to sleep whenever we leave) Most of the time when Lucy growls at Rio, it's when Rio was close to her when she (the dog) was playing with one of her toys (and she is very protective of her toys and treats, growling and/or snapping at anyone who tries to take them away when she's actively playing with them). However, sometimes Rio walks right by Lucy when she's eating her food, and Lucy just glances at her and keeps eating, other times she growls at her to make her back off. Lucy also has a habit of barking at pretty much everything on four legs that shows up on the big screen tv, despite our repeated attempts to curb her behavior.

Lucy doesn't get very much exercise daily, although we are planning to change that (it's mostly because of the cold and snow outside, we used to walk her every day), and she's reasonably well-behaved. She listens when we give her commands, and aside from the whole thing with the tv she usually stays quiet and fairly mellow. (she does bark when she gets really excited when we play with her, or at the vacuum or when there are other dogs barking outside, but she'll stop if and when we tell her to) She's also fairly well-behaved when we go on walks, we've had to train her to stop barking or trying to get close to other dogs on walks.

Thanks again for the advice, I've shared it with the rest of the family, and we've agreed to start training Lucy. We'll see if we can teach an old dog new tricks.

Edit: Also, yesterday when this happened we'd been cleaning the house. Lucy doesn't like it when she's left alone when we go on trips (we always get someone to watch her when we go on vacations) and she's learned that the difference between us going out for dinner or a movie, and us going on vacation is that we usually start cleaning a few days before we leave. In this case we were cleaning up because we were having company over, but she obviously didn't know that. She might have just been on edge yesterday, but that still doesn't excuse her behavior.

One thing I've learned is that a pooch is never too old to learn! Bogie is still learning, and he's over 14. Just takes time and patience. :) Mental stimulation is just as important for dogs as physical exercise.

Sounds like the guarding is the main problem, and you can use these same techniques to work on those issues, too (both guarding her toys and food from the cat and the humans).

Good luck! Feel free to message me if you have any questions.

We've been having a similar problem between our 4 month old puppy and our cat. The dog is just wanting to play, but the cat is very stand off-ish and rarely wants to play. Recently, we have noticed that the cat is missing fur on the back of her hind legs either due to the dog or the fleas who accompanied the cat when she was adopted. Both are fixed and we've made sure neither of them are territorial. Both are adoptions. The cat was a stray found under the hood of a car and the dog was adopted from a shelter.

We've started training with the same methods Etters described and it's made a considerable difference already. Another thing to remember, if they never mentioned it at the obedience training, is to remain calm yet firm. No yelling and no physical reprimand, i.e. hitting. There is a series by Gary Jackson on YouTube about obedience training and basic behavioral problems, if you'd like to look into what he has to say.