Q:  I have a 10-week-old small-breed mixed puppy who is very playful. He enjoys playing with my cats, and they play back with him. Sometimes he plays a little too roughly with them, such as grabbing an ear, and they start to cry. But they don't do anything about it. They sit there and take it. Is that normal? I don't want him growing up picking on them, but at the same time why aren't they putting him in his place a little bit better?

A:  Let's start with your cats. There could be any number of reasons why they don't fight back when your puppy gets a little rough. There's evidence that dogs and cats raised together learn to interpret each other's communication signals. If your cats have lived with other dogs, maybe they've learned from prior experience to expect that a playmate dog will back off if they "yelp." If your puppy does draw back when one of the cats cries out, then the cry is doing its job as communication and the cat doesn't need to escalate — it's already gotten the result it wants.

A less pleasant possibility, of course, is that your cats are intimidated, or have been intimidated by other dogs in the past, and so have learned that asserting themselves is dangerous. And a third possibility is that neither side really knows how to communicate with the other.