A boy with a bb gun on his grandfather’s ranch and the entire summer before him is the richest man in the world.

I was eight years old. My grandfather bought me a pump-model rifle and one of those milk cartons full of bb’s, and I had endless acres of irrigation ditches to explore, hunting frogs. They’re naturally camouflaged little buggers—all green and brown blotches just the color of muddy water and moss—and they’re smart enough to lie very still until you’re almost upon them. They know if they move they’ll reveal their location (a lesson learned by many a lost frog thanks to the herons that have hunted them since time gone by).

My early successes were minimal. I tried sneaking up, but the little amphibians would remain...