Tarsiiformes is an infraorder of small primates. It contains a single extant family, Tarsiidae, and members of this infraorder are called tarsiiformes, with members of the family named tarsiers. Tarsiiformes is one of the six major groups in the order Primates. They are found in Maritime Southeast Asia, primarily in forests, though some species can also be found in caves or wetlands. They range in size from the pygmy tarsier, at 8 cm (3 in) plus a 20 cm (8 in) tail, to the Philippine tarsier, at 16 cm (6 in) plus a 25 cm (10 in) tail. Tarsiers are carnivorous and primarily eat insects, though they also consume small vertebrates such as lizards, birds, or bats. The only tarsier with a population estimate is Niemitz's tarsier, estimated at 10,000 to 20,000 mature individuals, but it, along with the Peleng tarsier, pygmy tarsier, and Sangihe tarsier, is categorized as endangered species, while the Siau Island tarsier is classified as critically endangered.
The fourteen extant species of Tarsiiformes are divided into three genera: Carlito and Cephalopachus, each with a single species, and Tarsius, containing the other twelve. A few extinct prehistoric Tarsiiformes species have been discovered, though due to ongoing research and discoveries the exact number and categorization is not fixed.[1]