By the weekend, I needed to get out; I went for a run. I started long-distance trail running in 2013, at a time when I was entangled in a web of depression and anxiety. By the time I ran my first 38-mile ultramarathon, eight months later, I was significantly less depressed and moderately less anxious. Running has been my medication and meditation ever since.

As I ran through Tilden, though, all I felt was fear. At the top of a hill, I saw a runner, standing in place. He looked pale.

“You O.K.?” I asked as I came up to him.

“Yeah,” he said in a hushed tone, pointing.

There, about 10 feet in front of us, a snake was writhing on the path. I stared, gulped and prepared to slowly backtrack. Then I realized it wasn’t a snake.

It was two snakes, their sleek bodies wrapped around each other, rising and falling, mirroring each other in twisting S-shapes.

“Rattlesnakes, I think,” the runner said. “And I think they’re mating.”

I snapped a short video on my phone. Without that video, I’m not sure I’d trust the memory of what I saw. I watched for a few more seconds, turned, and ran back down the hill.

II. Mountain Lion

As the weeks passed, my brother began to show clearer signs of recovery. He was transferred to a rehab facility in Vallejo, Calif., where he gave impromptu lectures on space travel, the American prison system, the Symbionese Liberation Army and why Bob Dylan deserved the Nobel.

Eventually, the delirium faded, and Jesse was able to walk, shakily, with help from the physical therapists. Still, he wasn’t sleeping well, and he was confused, frightened and hurting. His injury was still so severe that even the most optimistic doctors told us to expect months of rehabilitation. Would he make a full recovery? No one could tell us.