Getting faint about blood isn't very evolutionarily sound, is it?

If a predator takes down one member of the pack on the savanna, a pack mate fainting would rather ensure that member's removal from the gene pool. Easy bonus for the predator: "I chomped one and another fell down!"

Alas, I've always been one of the squeamish. (Another trait I get from Dad.) But here's what's interesting: It's selective.

A-Okay

• FrogDog has a lot of health care clients. I've seen cadavers covered mostly by sheets with just one or two body parts exposed. No problem.

• Live surgeries may evoke an "ick" face when innards come out of gaping holes, but I don't get lightheaded.

• I'm no longer into horror movies, but Freddy and Jason and all the movie villains of my youth never made me feel ill. Scared, maybe. But not faint.

Bring on the Smelling Salts

• My college boyfriend cut his hand when feeding my cats canned food one morning. I had to put my head between my knees when he said, "[Expletive!] Sliced myself. Blood gushing everywhere!" I didn't even see the blood.

• At a benefit luncheon, a speaker told the story of her heart transplant. Her description of how it felt for her heart to be failing, her fear in the face of impending death, the medical treatment needed before they found a compatible heart, the preparation for surgery, and her description of the surgery got me. I couldn't eat my food. I had to discreetly lower my fuzzy head.

• At Body Worlds, I was fine with the petrified body parts in cases. My headlights started to falter when I got to the man standing at the end of the first hallway holding his skin—with eye holes and freckles and hair—in one hand. Then I turned to my right and saw a room full of dead people in living-people poses: talking on cell phones, playing poker, riding horses. I had to sit down. I recovered, but every time I heard a docent explain the specimens in detail, I needed a breather.

So what's the deal?

The Body Worlds experience makes me think it's about mortality. When blood and guts and danger are removed from connection with someone knowable, I'm fine. Actors in a film? Anonymous bodies covered mostly by sheets? Shrug. But when the cadaver or gore associates in my mind with a living, breathing person, I falter.

Death is inevitable. But I can still be angry at its injustice. I cannot fathom it, and I do not want it. The people in my life are what make it worthwhile. Unreasonably and impossibly, I want us to live forever. There is so much to experience in this world. Vivid proof that it cannot last—that we are fragile and mortal—causes me visceral panic.

Is this true for all the squeamish? If you’re squeamish, is it selective in the same way?