A tortoise can say what a parent cannot

"You're losin' it, Mom," my son laughs, calling home from a pay phone one Sunday afternoon in the middle of his 14 weeks of basic training.

Losing it? Just because I asked him if he'd heard from Sponge Bob lately?

Sponge Bob is the real life baby tortoise Roman bought and named a few weeks before he enlisted in the Army. He is the latest in a long line of scaly creatures that this reptile-expert son of mine has brought home throughout his 19 years.

As the turtle's interim caregiver, I had recently begun writing letters to our soldier in training using the pen name "Sponge Bob." Unlike the ones signed "Love, Mom" these offered news of home from a distinctly amphibian perspective. Sponge Bob, after all, has an herbivore's appreciation for the vegetable garden Roman planted last spring. And this tortoise could write, "I'm proud of you," without sounding sentimental, because he would always add something like, "I'd salute you, Dude, but, hey, my arms are too short."

To hear Sponge Bob tell it, he and Roman are soul mates. Two guys in camouflage colors. One carrying around a 40-pound rucksack on long marches under the hot Southern sun; the other, lumbering under a lumpy shell near a heat lamp in a plastic tub in the guest bedroom.

OK, the Sponge Bob letters are silly. But they're fun to write, too. And the comparison between my soldier son and his fist-sized tortoise is not all that far-fetched.

Mid-December 2002: I'm sitting in the crowded bleachers set up in front of a barracks in Fort Benning, Ga. On my left is Roman's dad. To my right, Anne, his college-age sister. The three of us have flown here from San Diego for Roman's graduation from Advanced Infantry Training. We haven't laid eyes on him for more than three months.

"Do you see him?" I murmur, scanning the four long columns of the three new companies of the 2nd Battalion 19th Infantry Division marching in front of us.

"How would we know?" Anne asks.

She has a point. With their uniforms, shaved heads, and serious expressions, the recruits look amazingly alike. I envision their drill sergeant barking, "Any of you mama's boys dare to smile at your families out there, it's 100 push-ups after the ceremony!"

The marching soldiers stomp to a halt. In the row directly in front of us stands a young man who looks somewhat familiar. His shoulders are broader than I remember. He seems taller, too. His dark eyes stare ahead with a fierceness I've never seen in them before. The thin line of his mouth does not move, but all of a sudden, his eyebrows do. Up and down. Up and down. A covert "hi" for the three people in the bleachers who share his last name.

My son, Private Groucho. Alternately tough and tender, with a shell of invincibility offset, now and again, by an unmistakable vulnerability. Hard on the outside. Softer within. The boy, the man, sharing the same olive-green uniform.

Roman is home for three weeks of leave before heading for his first assignment, a two-year tour of duty in Germany. Many months ago, I'd tried to talk him into college instead. Now, having come to terms - as much as any mother can - with his choice, I want to hear all about basic training. About the work and the food, the people he met, the things he learned.

Sometimes Roman will open up and talk, more than he used to. He spoke at length about what the different bars of color mean above his uniform's jacket pocket. "This one can only be worn by those who serve in time of war," he said matter-of-factly.

Today, studying the photo of the men of Alpha Company, Roman's unit, I ask, "So, which one is 'Eyeball'?" "Eyeball" is the nickname of the guy assigned to be his "battle buddy" in Germany.

This time he sighs, "Mom, why do you always ask so many questions?"

The march to independence and autonomy isn't easy. Not for our children. Not for us, their parents, either. And I believe there comes a time - it might be a moment from now, it might be several years - when in their search for their place in this world, we will, as we must, lose them for a while.

It's the day Roman leaves for Germany. He and his dad and sister say their goodbyes at home. A morning person, I've volunteered for the 4:30 a.m. drive to the airport. We chat a little in the car. About the emptiness of the freeway, the fog, his layover in Atlanta.

A hard rock CD - one of his, Linkin Park - thumps in the background.

"I've been telling people for months I'm going to Germany, like it's no big deal. But now I'm actually doing it," he says, adding softly, "Weird, huh?"

Weird indeed.

At the airport, he's all business. Checks in at the ticket desk. Gives me a quick let's-not-make-a-big-scene-here hug. Puts his backpack on the conveyor belt at security. Scoops it up on the other side. Striding toward Gate 38, he raises a hand and waves it, but without so much as a backward glance.

"He's gone," I think. "In more ways than one."

My eyes fixed on the back of his head, I try to reconcile myself to the push and pull of this thing called change.

I stop waving. What's the point? Just as I do, I see him turn and double back across the wide hall of the terminal. He stops within about 20 yards of where I'm standing. To get any closer, he'd have to answer to a security guard. At first I think he might have forgotten something. But that's not it.

He has returned to snap my photograph. The camera hides his eyes. Mine - brimming now - have no such protection.

Back at home, I carry a plate of lettuce with an extra helping of shredded carrots over to Sponge Bob.

He pokes his head out of that hard shell of his, blinks up at me and, I swear it, smiles.