I’m a writer. Or at least I’d like to think so. Lately I’m a camera assistant for National Geographic photographer Charlie Hamilton James, as well as his wife. People are usually more interested in his job than mine, keen to know what it takes to get those amazing shots.

Charlie is photographing cutthroat trout, so most mornings we set out for the Snake River in Grand Teton National Park. Our goal: to photograph otters eating cutthroat.

But first, we have to find them.

It’s December, minus eleven. One of the most popular parts of the park is deserted. I wear layers of thermal clothing. I look like the Michelin Man. The snow comes up to my hips. If I fall over I might