with them, but after a few minutes, we are left far behind. Their ever more distant baying is our only guide, and we move forward slowly. Fortunately, there are few nauyacas or fer de lance, poisonous snakes whose bite under these circumstances could be deadly.

We walk more than three exhausting hours. When everything seems to indicate that we've lost the dogs, we hear them bellowing in the distance. They've stopped running. They've driven a cat up a tree!

10:30 am

Twenty minutes later, when we finally catch up to them, Javier meets us with a broad grin. We have an enormous male jaguar! Cuauhtémoc prepares the tranquilizer rifle, and in a few minutes, we have the jaguar on the ground.

We put drops in his eyes to protect them and cover his face with a clean cloth. We measure his body, weigh him, and take blood samples, making sure of his sex and general physical condition. We constantly monitor his heartbeat for possible negative effects of the anesthetic. When we're done, we put a radio around his neck that will allow us to follow his wanderings for the next two years. The necklace has a transmitter that emits a signal that will tell us the animal's position. Our continual monitoring of the