tarsiiforms

Tarsiiformes are an infraorder of primates that includes the living tarsiers in the family Tarsiidae and numerous extinct relatives. In modern classifications, tarsiiformes are placed within the Haplorhini (the “dry-nosed” primates) and are more closely related to monkeys and apes than to lemurs and lorises. The extant clade is restricted to Southeast Asia, with members found in the Philippines, Borneo, Sumatra, Sulawesi, and nearby islands.

Physical characteristics include small body size, disproportionately large eyes adapted to nocturnal vision, large mobile ears, and a specialized ankle and foot structure that enables vertical clinging and leaping between trees. Their elongated tarsal bones give the group its name. Tarsiiforms are primarily arboreal and nocturnal insectivores, feeding on insects and small vertebrates, and often forage alone or in small units.

Social organization varies; many species form pair bonds with a single breeding pair and their young. They have a relatively short gestation period and typically give birth to a single infant, which clings to its mother as it learns to leap. They are known for their calls and nuanced social behaviors.

Fossil tarsiiforms date back to the early Eocene; the fossil record includes numerous extinct genera and species from Asia and Europe, illustrating the early diversity of this lineage. The survival of the modern tarsiers into the present day marks a long, relatively narrow branch within primate evolution.

Today, several tarsier species are threatened by habitat loss, fragmentation, and hunting; they are a focus of conservation efforts.