Like other animals, my hypothesis is that the majority of wild snakes live drastically shorter lifespans than domestic ones, due to the various difficulties of living outside, i.e. finding shelter, finding a regular source of water, predators, so on and so forth. That was the first thought I had after reading the author's last paragraph about how naturalists didn't know how long snakes live in the wild. But then again, who knows!
It might be that they may live for longer since there is more freedom for them outside. I can't go out and ask one. "Hey Herman, how old are you?" That was the name of my mother's pet snake from her horticultural exploits. Besides, it is rude to be so point-blank about someone else's age. The way I figure out any of my friends' ages is a math game. So-and-so is x months older or younger than me.
So that is what I left off reading this book considering.