CACHICHIRA, Bolivia — The hunt began at nightfall under a crescent moon and with a chorus of frogs, which suddenly went silent when the rifles fired and the thrashing erupted. The bodies were dragged onto the deck of three boats: Six crocodilians were landed one night and 14 the next. Some were nearly eight feet long, head to tail.

As gastronomy leaps from one trend to the next, the search for the next new thing has become a quest without end for many chic restaurants. And the role of the chef is changing, too: The greatest cooks these days are also the greatest storytellers, not just serving up meals, but also long yarns about the who, what and where of the origins of their ingredients.

Which is why I was with some of the finest chefs in the Andes at Lake Colorada in northwestern Bolivia, home of the spectacled caiman — a relative of the alligator.

Once every few years, a group of cooks and owners from acclaimed restaurants in Bolivia, Argentina and Peru hire a river boat to take them to places unlisted in the Michelin Guide and where no food critic has likely ever dared to tread.