The monotony of the trail had made me weary, then I heard the unmistakable buzz and saw movement in the trail ahead of me. Not three feet away was a giant rattlesnake coiling to strike. I was instantly terrified, energized and alert.

I recognized the feeling from about thirty years ago when I was snorkeling in the Red Sea off the coast of Saudi Arabia. I had joined a group of English people from the compound where I worked and we were camping on the Red Sea south of Jeddah. They had snorkeling and diving equipment and loaned me a snorkel and mask. The shore was mostly coral, so I could wade out a ways then drop about fifteen feet down the coral face. It was beautiful, but the sea floor sloped off into the distant haze, the gray wall.

I found it intimidating to be swimming alone in deep water with just the one coral wall as a boundary. So, I stayed close to shore where the more interesting stuff was, anyway. I kept an eye on the gray wall in the distance, just in case.

At first I couldn’t tell what it was, then the dark shape moved closer. It was a shark, cruising near the bottom about sixty yards out from the wall — and me. Looking just like the sharks in movies and aquariums, it sinuously glided by until I lost sight of it again. I nearly drowned trying to regain the breath I had been holding.

Dark water has always made me uneasy, probably from swimming in all those duckweed-filled farm ponds when I was a kid. I also had the misfortune of seeing the just-released original “Jaws” the night before a spring break vacation to Hilton Head.

It was crowded on a holiday weekend, and the Hilton Head resort’s long flat beach means you have to go quite a ways out to get very deep. Apparently every one there had seen the movie too, because no one ventured out too deep unless others were at least equally far out. Over time the outer edge of people would ease further and further out, dragging the rest of the swimmers along with them.

Suddenly, someone would jump up and exclaim from stepping on a crab or being bumped by a sand dollar, and everyone nearby would panic, jump and immediately make a break for the beach. Up and down the beach the outer edge of people in the water would hold momentarily, then falter and every one quickly pulled back up on the sand. No one wanted to be exposed – to whatever it was! The men toweled off nonchalantly and acted as though they needed more suntan lotion or a drink of water and the women checked on the kids. The scenario was repeated throughout the weekend as the whole crowd got more exercise from running than from swimming.

But back at our Red Sea camp, when a couple of the more experienced guys who had been diving further away from shore asked if I had seen the shark, I calmly nodded. “Have you seen sharks in the wild before?” one asked, “How big do you think it was?”

“Never before,” I considered, “Maybe six feet.”

“Wow,” he replied, “That’s right. We’ve seen quite a few, and were very close. That’s what we thought, too.”

I enjoyed the little bit of respect that came with that comment, but was glad he didn’t ask how I had arrived at the estimate. My adrenaline had kicked in when I recognized it as a shark, and after determining that it wasn’t coming directly at me, I considered its size. I figured I had probably overestimated the length so, when they asked, I halved the number, then halved it again. Half of 24 is 12; half of 12 is 6.

So yes, the burst of adrenaline felt familiar when I encountered the rattlesnake the other day. I froze, then slowly backed away, speaking softly to the snake, telling him he was doing the right thing to alert me and he was an even better snake to move off the trail and let me go by. Once I backed away, he slowly uncoiled and stopped buzzing. I got a good look at him as he very slowly slithered off the trail into a dead yucca plant, and was hidden in the brush. I moved on without incident.

Upon solemn consideration and some quiet reflection when I got back home, I believe the snake to have been about two feet long. That’s my final estimate. You can do the math to figure out my initial one.