For the 18 months we've had our two guinea pigs, we've felt a need to look out for the little guy, Delmo.

Tapper (right) is our Alpha Mouse, and he lords it over his little brother all the time. Tapper is the fat pig. New food in the cage? Tapper first, thank you. Is that hay? Outta the way, Delmo. Water? Age before beauty, brother.

Perhaps our table manners have no place in the cage, but we are who we are and we just can't help it. Many a time we've held Tapper back and let Delmo have first go at the fresh food in our interest of fair play and justice. We can be ridiculous. The pigs, wielding their own form of chivalry, never let on to notice. We thought we were doing a good thing.

Doing good. Like all those good eggs we know who chase the squirrels from the bird feeder because they heartily resent the big, bushy-tailed rodents crashing the party they put on for the delicate feathered friends.

Silly us to think we know better how it should be.

Yesterday after I put the breakfast serving of guinea pig food in the cage, both guineas came to the door. I stroked them both simultaneously, and they purred with pleasure. Then Tapper craned his fat little neck to nibble his salt wheel. Finding it good, he nudged Delmo's nose over, and Delmo had a taste.

My daughter, who has read just about all the books on her rodents, melted. "Ooohhh," she said, "Tapper was making sure Delmo had some, too."

"So Tapper takes care of Delmo, even when he's being pushy?"

"Probably, mom. You know how Delmo cries whenever he can't see Tapper? Maybe that's why?" It's true: the little guy squeals up a storm if his big brother is out of eyeshot. Delmo depends on Tapper's company. Whatever it is about Alpha Mousiness works for both guinea pigs. They're good with it.

So there it is. I owe the fat pig a big apology. If being Alpha Mouse means being bossy, it also means keeping the kingdom safe. All hail Alpha Mouse.