Ever hear the joke about space aliens who arrive here and believe dogs are in charge because humans follow behind them and pick up their droppings?

Those of us with companion animals can smile at the absurdity, but we understand how reading the daily poop puts us in charge of our pet's health and well-being. The distasteful task of cleaning up after an animal quickly becomes a labor of love.

Years ago, my family was amazed when my newfound dog devotion caused me to squelch notorious queasiness and mop up after my puppy with a baggie "glove." I had no choice if I wanted to keep a dog in the city. Canine waste is a pollutant, and ordinances levy fines against dog walkers caught leaving the scene of the grime. Scofflaws ruin it for everyone — especially for people who step in the stuff.

If cleaning up after my dog began as a bow to political and social pressure, the practice is now an everyday reality check. I get a glimpse of my pet's innards and know my pooch's plumbing as well as my own. This inter-species physical familiarity is a remarkable aspect of our unconditional bond.

Adults change the diapers of babies only until the kids are toilet-trained, and parental knowledge of youngsters' bodily functions fades. But pets never outgrow the need to be looked after, scooped up after. Our intimacy with their bowel, bladder, sleeping and eating habits endures as long as our relationship with them lasts.

This unique closeness may seem potty to people without pets, but it creates a community of comfort among caretakers who gather wherever the dogs run, such as at neighborhood pet shops and park play groups. In polite company, even with a spouse, we might never bandy about our own loose stools. But in canine company, a mutt with diarrhea provides an unblushing excuse to share.

Has your dog gotten into the trash? What food do you give? Is your animal on any medication? Such are typical questions posed to worried dog owners by Rob Van Sickle, co-owner of Polka Dog Bakery in Boston's South End, the city's canine-friendliest neighborhood. "Stool talk is ubiquitous," he says. And homeopathic solutions are swapped. At Van Sickle's shop, I learned about the healing properties of Greek yogurt for my 8-year-old terrier's sporadically sour tummy. A daily teaspoonful has turned the peptic tide for him.

Pet keepers share other home remedies: A temporary diet of boiled chicken and white rice is the canine equivalent of chicken noodle soup for people.

We coddle them, but dogs are durable. For centuries, they went off by themselves to take care of business. Now, pet owners are on the front line of defense in prevention. A walk with the dog, always a healthy exercise, is even more crucial to pick up clues about what's going on in the belly of the beast.

Monica Collins writes the syndicated column "Ask Dog Lady" (www.askdoglady.com).