What's on your mind, Ruthie?

Ever wonder what your dog is thinking? Or if he/she is thinking?
I've watched enough episodes of The Dog Whisperer to recognize how often people mistakenly assume their dog has human intelligence, so I don't have any illusions about Ruthie the Wonder Dog delving into higher mathematics or arcane philosophy.
But there is an unmistakable intelligence and a discernible thought process going on in her furry little head.
I've heard it said that a really smart dog is about as intelligent as a 2-year-old child. Maybe so. I do know that Ruthie is the smartest dog I've ever owned, or who has ever owned me.
I was reminded of the fact that she has thoughts about 4 a.m. today when Maria and I awoke to the sounds of her growling and whining in her sleep, apparently in the middle of a rather intense dream. Ruthie rarely sleeps alone. If she isn't on our bedroom carpet, she's in one of the kids' rooms at night.
I can't help wondering what memories and images are running through her mind in moments like that. Is she chasing cats? Rabbits?
When we went to the animal shelter to pick out a dog seven years ago, I took along my laser pointer. I was looking for an alert, responsive dog who took an interest in the little red laser dot. It was my little pocket dog intelligence tester, which may or may not have had any scientific validity.
Ruthie was the only dog in the bunch to show any interest in the laser dot and she went bonkers over it. She also behaved as if she recognized us immediately as her family, almost as if she'd been waiting patiently for us to show up and take her home.
We know nothing of her previous life. The shelter people guessed she was about three or four months old and said she'd been picked up as a stray. More likely, she had run away from her original home, got lost and was picked up by the dog catcher.
At any rate, the laser became her favorite toy.
I can stand on the deck behind our house at night and run her all over the yard in pursuit of the red dot. She'll chase it in tight circles until she gets wobbly from dizziness. She'll chase it up and down stairs until she's ready to drop.
She knows the click of the laser pen clip and will come running from the farthest corners of the house when she hears it. To my ears, it's indistinguishable from any other pen clip, but she knows the difference and ignores all of the others.
She also knows the word "laser." When she hears it, she starts looking around on the floor for the dot.
And while she loves retrieving tennis balls, her next favorite toy is a colorful rubber mallard we bought her for Christmas 2003. It's outlasted every other dog toy we've given her.
We used to give her stuffed dog toys, but she got so good at eviscerating them that she could have the living room floor covered with stuffing 15 minutes after she got her paws and teeth on one of them.
And, of course, she associates it with the word "duck."
One morning recently, Maria was recounting a phone conversation one of her coworkers had in which the newly married young reporter told the apparently disbelieving interviewee that her new surname is, "Dick. Dick! Dick!"
Moments later, Ruthie jumped up on the bed with her duck in her mouth, ready for a game of "pull the duck" or "retrieve the duck."