Vision All tarsier species are nocturnal in their habits, but like many nocturnal organisms some individuals may show more or less activity during the daytime. Unlike many nocturnal animals, however, tarsiers lack a light-reflecting area (tapetum lucidum) of the eye. They also have a fovea, which's atypical for nocturnal animals. The tarsier's brain's different from other primates in terms of the arrangement of the connections between the two eyes and the lateral geniculate nucleus, which's th… (More on Tarsiiformes)