Rafael Hoogesteijn, a respected veterinarian and jaguar biologist whose 1992 book "The Jaguar" is still one of the classic natural-history books on the species, now works with Panthera in the Brazilian Pantanal. As of this writing, he has had 79 jaguar encounters with up to four jaguars seen together at once. Twenty-two of the encounters occurred while he was walking alone and unarmed or when he approached a jaguar from a car, bicycle, motorcycle, or horse (other encounters involved boats, helicopters, and captures). During these encounters, each of which lasted up to 20 minutes, he followed jaguars traveling and watched them mating. Only once did Rafael feel threatened.
While following approximately 30 meters (99 feet) behind a male jaguar that was following a female in heat, the animal suddenly turned, roared, and charged straight at him, teeth barred, ears back, and nape hairs erect. Rafael stood his ground and the jaguar stopped 10 to 15 meters (33 to 38 feet) away, then turned and disappeared into the nearby river. Perhaps this was a bluff, or what Rafael called "a mock attack." Perhaps, had Rafael turned and run, the outcome might have been different. Clearly the jaguar must have felt threatened and reacted explosively, but then it reassessed the situation and made the decision to stand down. Killing or hurting Rafael would have accomplished nothing for the animal, except perhaps injury to itself.