Since 2009, Yates estimates that he has gone after the animal on roughly 100 different occasions. The monkey was his white whale. He claimed to have darted it at least a dozen times, steadily upping the tranquilizer dosage, to no avail. The animal is too wily — it retreats into the woods and sleeps off the drug. A few times, the monkey stared Yates right in the eye and pulled the dart out.