Adaptive primate radiation refers to the rapid evolutionary diversification of a single ancestral primate lineage into multiple new forms, each adapted to a different ecological niche. This process typically occurs when a group of organisms colonizes a new environment or when significant environmental changes create new opportunities. Key drivers include the availability of new ecological niches, the absence of competitors, and the evolution of novel traits that allow for exploitation of these niches.

For primates, examples include the diversification of lemurs in Madagascar, which evolved into a wide array of species occupying various niches from nocturnal insectivores to diurnal folivores, after colonizing the island free from mainland competitors. Similarly, the evolution of New World monkeys in South America, following their dispersal from Africa, led to a radiation into diverse forms adapted to different arboreal lifestyles and diets. This process is characterized by rapid speciation, often involving significant morphological, physiological, and behavioral adaptations driven by natural selection acting on genetic variation within the population. Adaptive radiation is a fundamental concept in understanding the vast diversity of primate species observed today.