I’ve been wondering for years if dogs can really smile, reading every book and behavioral study I can find about it.

I don’t believe Frieda has ever smiled and neither do most of the strange people and animals she encounters, who often end up running for their lives. I never saw Rose show any expression remotely like smiling. I often thought she was disgusted with me, and would show up with a briefcase to resign and look for work on a sane farm.  Lenore sometimes has a look I would consider a smile, especially if there is something disgusting to eat, and so does Izzy, who not only seems to be smiling, but laughing at me. Izzy is smooth, a charmer.

I want to start off this subject by uttering the three words rarely, if ever heard in the realm of animal behavior – I don’t know.

I don’t really know if dogs smile, even though many dog lovers insist that they do (almost as many as say their dogs are abused, grieve like humans, or suffer separation anxiety.) People tell me all the time they know exactly what their dogs are thinking, but I do not have that gift, except when food is involved or taking a walk. I don’t think anybody else really knows if dogs can smile either, although there is no shortage of opinions about it.

I had the good fortune to write a blurb for behaviorist Stanley Coren’s fascinating new book “Dog Dogs Dream,” out in July from Norton, Inc. and Coren gamely takes on a lot of these questions.

But he isn’t sure dogs smile either. “Even if we believe that dogs actually smile,” he wrote, “there is still the question of whether they can ratchet their emotional expression up a notch and produce something that is the canine equivalent of laughter.”

Some researchers believe dogs do laugh. I am wary. I think animal researchers understand where grant money comes from.  Nobody ever a research grant or book contract or TV deal to show that dogs are stupid, cowardly, unfeeling or incapable of laughter. Lots of money is spent each year measuring the words a border collie knows – we’re up to about 1,600 now, I think. I’ve always been puzzled as to why a border collie needs to know all of these words. The only words Rose ever cared about was “get the sheep.” We didn’t discuss politics or religion.

Nobel Laureate and dog lover Konrad Lorenz believed that dogs are capable of laughing and they do so mostly when they’re playing. This canine smiling begins with the slight opening of the jaws, revealing the tongue over their front teeth.

I see, as Coren did, that there is one facial expression that comes close to what we mean by smiling in humans. In this expression, slightly opened jaws reveal the dog’s tongue sticking out over his front teeth. Or the open mouth with what appears to be a smile, as Izzy is showing in the above photo. Is Izzy smiling? Truthfully, I don’t know.

When I took this photo I was telling him a joke about a border collie and a sheep. I can’t repeat it here. So maybe it is so.