The Philippine tarsier measures only about 85 to 160 mm in height, making it one of the smallest primates. The average adult is about the size of an adult human fist. Philippine tarsier's eyes are fixed in its skull; they cannot move in their sockets. Instead, a special adaptation in the neck allows its round head to be rotated 180°. Their eyes are disproportionately large, having the largest eye-to-body size ratio of all mammals.
The Philippine tarsier is endemic to the Philippine archipelago. Established populations are present primarily on the islands of Bohol, Samar, Leyte and Mindanao. Its habitat includes tropical rainforest with dense vegetation and trees that offer it protection such as tall grasses, bushes, and bamboo shoots. It prefers dense, low-level vegetation in secondary forests, with perching sites averaging 2 m above the ground.