It's time for another installment of our popular and informative series "Gross things dog do." Today's topic is ""Why dogs think we want to look at their nasty undersides."The subject is Daisy the Golden Lab who took up residence at our place immediately after my kids first saw her and she rolled over to have her belly scratched. This is one of those times when children and adults react very differently to the same visual information. To an adult, which I consider myself to be a good 70-80 percent of the time, the underside of a dog, with all those spigots and things, is not its most comely side. But kids, even little kids, seem to be instinctively drawn to scratch the bellies of dogs on their backs. Why is this? Is it the residual reaction from an earlier evolutionary stage when our starving ancestors ate blood ticks or something? Maybe the overturned pooch was the origin of the Denny's buffet.Anyway, we went to see Daisy not long after the demise of Pollyanna, a poorly chosen moniker if ever there was one. Pollyanna, or Polly for short, didn't roll over to have her belly scratched, nor did she have any of the annoying habits of other dogs that have taken up residence at our place, such as depositing dead armadilloes on the porch. But she did have one inconvenient and somewhat embarrassing habit -- namely, killing other dogs on sight. It's not easy to explain to neighbors why their beloved Sport or Blacky won't be coming home tonight.But Polly got old and sick, so we sent her, with the aid of the veterinarian's needle, to that great overturned garbage can in the sky where she is in a state of eternal bliss rummaging through styrofoam hamburger trays and turkey carcases, which is the universal annoying habit of all mortal dogs.A few months after Polly's euthanasia, in a moment of foolish forgetfulness, we mentioned to some friends that we missed her. It just so happened that they had, at that very moment, a dog of their own that was confined to a leash in their back yard because of the city leash law, a dog that yearned to be free. They said Daisy was affectionate but still a good watch dog - the ideal pet for a family in the country. Which was all true enough. But in any sales pitch, it's what they DON'T tell you that you need to be concerned about.What they didn't tell us is that rolling over and exposing herself in a very unladylike manner is the standard Daisy greeting. Well, actually it's Stage 2 of the standard Daisy greeting. Stage 1 is growling ferociously until the one approaching the house gets to within, say, 10 feet. Then Daisy rolls over with her legs spread wide and her eyes closed and tongue hanging out, looking look like road kill. Maybe she's part 'possum. Who knows? All I know is I'd rather look at her bared teeth dripping slobber than her underside.If a burglar ever comes to our place I sure hope he's either afraid of big dogs or has a weak stomach. If Stage 1 doesn't stop him, maybe Stage 2 will.In the meantime, Daisy goes straight to Stage 2 every night when I come home from work. As soon I get out of the car she's right there on the driveway, showing her everything with no shame whatsoever.I mentioned earlier that I'm an adult 70-80 percent of the time. Well, darn it, not when I get home from work. However determined I might be to ignore Daisy when I leave in the morning, it's hard not to give her a little scratch when I get home.