He twisted me like a corkscrew as he dragged me to the river bottom in a death roll

In April this year, I was diving for fossils in Peace river in Florida, not far from where I teach marine science at a private naval academy. At 24, I’d been diving in the area for six years without any problems, and was guiding the dive for two friends, including Jake Koehler, who films videos of his underwater finds for his YouTube channel, Dallmyd. Because of the danger from alligators, we’d usually drop anchor on a particular spot, and bang on the boat and throw rocks to disturb them, as they tend to avoid contact with humans. But we hadn’t got much on film that day, so we decided to take a chance and do something unusual: instead of staying in one area, we jumped in the river and drifted backwards with the current.

I drifted into a very narrow channel, about a quarter of a mile ahead of the others, wearing my usual scuba gear: an oxygen tank, a lifejacket and weight belt. I suddenly felt an intense pressure on my left ankle, and, for a split second, I thought it was Jake messing about. We’d been joking earlier that my black wetsuit made me look like bait – the other two were wearing camouflage wetsuits. But then the pressure became unbelievably intense, and I realised it was a gator.