The Order Primates is a group of mammals that includes lemurs, lorises, tarsiers, monkeys, and apes (including humans). Primates are characterized by flexible hands and feet with opposable thumbs or big toes, forward-facing eyes that provide stereoscopic vision, and relatively large brains for complex behaviors and social interactions. Most primates are arboreal, living in trees, though some are terrestrial, and they exhibit diverse diets ranging from fruits and leaves to insects and small animals. Social structures are often complex, with grooming, communication, and cooperative behaviors playing key roles. Primates are found mainly in tropical and subtropical regions and are important for seed dispersal and maintaining ecosystem balance.