Then came motherhood.

Ta-da! My inner superhero revealed herself. In the right situation, talents I never knew I possessed sprang into action. Faster than a speeding bullet, more powerful than a locomotive, able to leap tall buildings in a single bound -- if one of my beloved children was in peril, that is.

It's not just me. It's mothering itself. One minute a woman stands in an empty nursery, battling butterflies and Braxton-Hicks contractions, wondering what she's gotten herself into and whether it's truly possible to love anyone as much as her DH. Then, pow! Ka-boom! Zounds! She gazes into that squinchy face and she's ready to lay down her life for a virtual stranger.

Is it the power of love? I like to think so. Scientists believe a mother's "vigilant protectiveness," as Japanese neuroscientist Madoka Noriuchi calls it, may be rooted in brainpower, too. Last year, researchers in Tokyo used MRI to show that particular areas of mothers' brains lit up when their children were in distress. They believe this means that a highly elaborate neural chain reaction orchestrates certain responses to cries. Having a baby also creates subtle changes in the brain that result in sharpened perceptions, says Katherine Ellison in her book The Mommy Brain: How Motherhood Makes Us Smarter. A keen sense of smell in pregnancy keeps a woman away from spoiled food, for example, and more attuned hearing allows her to distinguish her own baby's cry -- changes that aren't merely cool, they help her keep a new life alive.

Frankly, the reasons for mom heroism matter less to me than the miraculous fact that it exists. Holy weirdness, Batman! Why didn't anybody tell me about this? So my own mother wasn't the only one to have "eyes in the back of her head" and a sixth sense about how the kids who were playing quietly, not the shriekers, were the ones up to no good. Each threat I've vanquished brings confidence for the next crisis. And a secret relief, too: "Phew! I'm good at this mom thing!" So let's celebrate some heroic traits you never knew you had.