Mammals include badger, fox, pine marten, red deer, sika deer, and red squirrel. The Formosan sika deer is endemic to Taiwan. China produces 400 tons of predominantly Sika deer velvet antler annually. The owl, pheasant, magpie, sika deer, and Chinese bamboo partridge were commonly hunted and consumed. Red foxes and sika deer also inhabit the area. The main predators of sika deer include tigers, wolves, leopards, and brown bears. Concern instead turned to damage caused by sika deer, wild boars, and Japanese macaques. Insect infestation and sika deer foraging have become big issues. The Japanese macaque has been observed attempting to mate with the sika deer. The woods in the park are currently severely overgrazed by sika deer. The most valuable antler velvet comes from the sika deer which is raised on farms. There are Sika deer on the island. "Zoysia japonica" makes up a large part of sika deer diets. There is a large population of non-native sika deer on the island. It is estimated there is also up to 1000 Sika deer in Killarney National Park.