Donahue, who tracks jaguar sightings for ecotourism operator Southwild in Mato Grasso (map), arrived at the scene to find an animal named Mick Jaguar hidden in thick grass, stalking a nearby group of caiman yacaré, a crocodile relative native to South America (pictured).

"Over the next 30 to 40 minutes we watched the jaguar very slowly slink along in the direction of the yacaré," he wrote in his field notes.

The largest of South America's cats, jaguars are good swimmers and regularly prey on fish, turtles, and caimans. They also eat larger animals such as deer, peccaries, capybaras, and tapirs.