The wife and eldest son like squeezable margarine.

Only squeezable margarine products in the store last time she got groceries were either blue or pink.

Yeah, blue and pink margarines. No yellow. Guess I shouldn't be surprised, after they came out with green ketchup. She opted for blue.

One of the advantages of having heelers, or just about any dog for that matter, is that they serve as biological garbage disposals. Any meaty or cheesy leftover that your taste buds tell you is too old and not fit for human consumption is usually just fine for a heeler.

Saves having to put up with the smell of garbage in the house. About all that gets thrown away is paper, plastic or vegetable matter. Reduces frequency of trips to haul garbage outside.

And to top it off, they think you're being especially generous if you pass your garbage on to them. They love you for it. They begin to expect "extras" in their bowls, and look at you like you're an idiot if there isn't something special in there (hence our periodic purchases of cheeseburgers, plain, for the nights when there is no "almost garbage" leftovers).

I've read several places that dogs are colour-blind. But most reliable reports I've read presume canids can actually see shades of blue, since their eyes have the color receptors responsive to blue light rays. Hence our interpretation of how the sisters know when we're heading out for work, since I don the not-blue shirt. (Nearly all of my civilian shirts are blue. Wife was quite surprised when I tried to buy a green shirt in Central City last month.)

But we have never really been certain about whether or not they can see blue.

Since heelers are such traditionalists who hate to have their routines altered, they always get fed in the same place each night. Separate places, to keep peace in the pack, and prevent thievery. Except, for the past few months, the little maskless heeler has been eating in bed.

Her regular spot was several meters from, but still in sight of, her dominant (and fat) mother. Who would try to steal her little daughter's "extras". And could intimidate her away from her bowl with just a look across the room.

Mother got fatter, little heeler stayed little.

One evening, eldest son altered the sacred routine by placing the littlest heeler's bowl on the bed between me and the wife.

And she ate it. All. In peace. In one sitting.

So, if we're in watching tv, that is her new dining spot. Dinner in bed.

So, enough background. Now to pull it all together.

Tonight's no-longer-fit-for-human-consumption extra was angel-hair spaghetti. Wife was quite dubious the heelers would eat it, as there was no meat, cheese or protein of any kind flavor.

So eldest son tried the usual trick employed to get heelers to like something that isn't really canid food.

He covered it with margarine.

Blue margarine.

As he set the little maskless heeler's dinner bowl down on the bed below the wife's knees, the heeler flew up onto the bed, eager for her repast.

And stopped dead cold. Staring into her bowl with shock. A look of disappointment (you have to know how to read heeler expression points) came over her face, and she sidled halfway around her bowl, eyes locked on the blue food, until she was almost in the wife's lap.

"It ruins it!" she was clearly trying to say, as she gave a gentle, pathetic muzzle bump against the wife's leg.

After we enjoyed our laugh at her expense, which clearly made the little heeler feel even worse, eldest son swiped a finger through the blue, and presented it for the taste test.

It passed. She charged in to have her meal, eating all the blue stuff off the top first.

And we conclude they can definitely see blue.