My son can’t stand to see me lying down comfortably. He seems to have some sort of instinctive need to keep me on the lookout for invasions of my personal space when I really just want to relax for a minute. Perhaps this is some holdover from evolution. Maybe lions and cavemen would all have been wiped out by sneaky foes with pointy sticks if the young of the group had allowed the older males to close their eyes and let down their guards for a minute.

Whatever his ancient justification, my son views the sight of me in any kind of reclined position as an invitation to climb all over me. I should say, when I am fortunate he climbs all over me. This is the gentle treatment. When I really need a good bruising, he climbs to the top of some piece of furniture, from where he leaps at me. So far, his strategy has been successful, as we have not yet been driven from our home by a sneak attack of creatures bearing pointy sticks.

Like millions of old lions, I suppose I could grow to live with this helpful effort to keep me ever vigilant, except that the lions must have had softer offspring. My son is the sharpest object we have in our house, and that includes the steak knives. His elbows, knees, and heels never touch me without making me wonder if we have a whetstone for such joints hidden somewhere in his room.

Some of these are almost as sharp as my son's elbows.

And, of course, a boy is going to use his sharpest parts when he needs to dig into the cliff face of his father’s mid-section. I swear I still have dents in my ribs that perfectly match that boy’s elbows. I’ve got two good knee prints in my back, in case the doctor ever needs a map to where my kidneys used to be.

I could probably even write off the dings in my ribs and my back as the occupational hazards of housing a three-year-old. But these are not my most vulnerable parts. I suppose my kidneys can shift over and shack up with some of my better-protected organs for a while, but I’ve got some extremely vulnerable parts that have no place to go. For better or worse, they are planted where God put them. They can’t run and they can’t hide. Together, we all live in fear of that ice pick my son uses for an elbow.

They always take the blood out of the cartoon versions.

I’ve learned to sleep with my hands cupped into a strategic dome of defense. Someday soon, I may start awake to a dislocated finger, but considering the alternative, I will chalk this up as a great victory for both fatherhood and the adaptive genius of evolution.