ON THIS FATHER'S Day, consider the seahorse, the mother of all fathers.

This delicate little sea creature, valued as medicine in Asian cultures and as key chains in ours, is on display at the National Aquarium of Baltimore, the most successful exhibit in the 21-year history of the aquarium.

It is the perfect family outing for Father's Day. That's because the seahorse fathers are the mothers, a role reversal unheard of anywhere else in the animal kingdom, except perhaps in homes where the mother is particularly overbearing or earning a much larger salary.

Father birds may sit on eggs and father Homo sapiens may teach their kids how to play catch, but father seahorses actually give birth, complete with contractions and pain. (The contractions are visible, but it is hard to know how scientists measure a seahorse's pain, since none of the laboring fathers has ever been heard to utter the strangled moan, "I want jewelry for this. Do you understand?")

The obvious question is, "Then why do they call them fathers?"

One answer might be that the female has a very high, very round, very dramatic chest that recalls implant surgery in another species, and the male has a low, soft, pouchy abdomen that recalls a beer gut in that same species.

But the right answer is that the female still produces the eggs. She deposits them in the male's opened pouch by inserting her "ovipositor." (I'm thinking of Freud right now.) And, after a Fred-and-Ginger dance to the surface of the water, the male disengages from the female, closes his pouch and churns the eggs around with his sperm.

Ten to 28 days later, his pouch enormous, he enters two to four days of "labor" during which he expels anywhere from 15 to 2,000 fully formed, completely independent baby seahorses, in many species not more than a quarter-inch long. And, while he's been carrying the babies, she's been mass-producing more eggs. He can be pregnant again by that afternoon.

Don't you love it?

According to Alison Scarratt, curator of fishes at the aquarium, and James Anderson, seahorse program manager, many people continue to believe seahorses do not really exist anywhere but in mythology, and if the current over-fishing and habitat destruction continues that may someday be true.

But the seahorse fun facts of interest to the readers of this column might be these:

* Male seahorses slurp their food. (Females do, too, but I am sure that's because they are so discouraged that they have ceased to care.)

* There is "tight pair bonding, at least for the season," said Anderson, but he did not say whether he meant Aspen or the Hamptons.

* The male will puff up his pouch and open it in front of the female to demonstrate that it is empty and ready for an egg deposit. I thought of all sorts of things to say here, but I couldn't stop laughing.

* The male will spend days hanging around the same sea grass or coral (literally: they use their tales) without moving, while the female seems to roam over an area 10 times the size of his territory. The human equivalent might be ESPN and a thousand stupid errands.

* As his pregnancy nears its end, the male eats less and is more lethargic. But immediately after birth, his pouch shrinks to an almost imperceptible bulge on his profile. That is so unfair.

* Seahorses can be found on the Chesapeake Bay, usually late for dinner, sunburned and with nothing to show for it.

Despite my cynical conclusions about the sex roles in the seahorse kingdom, I was captivated by the exotic little creatures so determined to avoid extinction that they have found a way to speed replication with this I'll-make-the-eggs, you-grow-the-babies division of labor.

And I am mindful of the lesson the male seahorse teaches the arrogant human female who thinks she alone makes miracles.

Forgive me, then, if I will continue to search the animal kingdom for the male of the species who is willing to come up with something different for dinner every night.