Goats were originally brought to the Galapagos Islands by sailors in the late 1800’s, and over the next century, they ate much of the vegetation on several islands, damaging many native plant and animal ecosystems. In 1997, Project Isabella was launched, in which goat hunters used helicopters and sniper rifles to diminish local goat populations. In less than a year, goat hunters realized that some goats were terrified of loud noises and ran away from the approaching helicopter noise, while others are less afraid and continued eating, making them easier to find and kill. Nowadays, almost all of the local goats hide in caves when they hear the sound of a helicopter approaching.