Goats were originally brought to Kaua'i by the Polynesian settlers. While they might have helped the Polynesians survive, they've become a nuisance in modern times. There are too few hunters to cull their numbers, a benign climate, and abundant food. Without the goats, this stretch of trail would be covered in green. In fact, it's interesting to think that many of Kaua'i's steep hillsides (along the Na Pali, and in Waimea Canyon) would look quite different without the ravenous hoardes of goats.