strepsirrhine

Strepsirrhini is a suborder of primates that includes lemurs, lorises, and galagos. It is divided into two infraorders: Lemuriformes, which comprises the lemurs of Madagascar, and Lorisiformes, which includes the lorises and galagos of Africa and Asia.

A hallmark of strepsirrhines is their moist nose, or rhinarium, and a split upper lip. They possess a toothcomb formed by the lower incisors used for grooming, and many have a grooming claw on the second toe. Their eyes often have a tapetum lucidum, and they typically rely more on olfactory and tactile cues than on vision. They generally show an incomplete postorbital closure (a postorbital bar), in contrast with the full orbital enclosure seen in haplorrhines.

Ecology and behavior: Strepsirrhines are mostly arboreal. Many are nocturnal or crepuscular, and their diets are diverse, including fruit, leaves, nectar, and insects. Reproduction tends to be slower than in haplorrhines, with small litter sizes; lemurs in Madagascar exhibit pronounced seasonal breeding.

Evolution and conservation: Strepsirrhini diverged early from the haplorhine lineage in primate evolution. Today they face habitat loss and hunting, with several species of lemurs and lorises classified as endangered or critically endangered.