Primates are a diverse order of mammals that includes over 500 species. They range in size from mice to humans. This document discusses the anatomy, behavior, ecology, and classification of primates. It notes that primates have grasping hands and feet, flexible joints, nails instead of claws, and large brains compared to other mammals. Primates live in forests and exhibit a variety of locomotion styles. Their general body plan allows for versatile living. The document outlines the major phylogenetic splits among primates and describes characteristics of different primate groups including prosimians, anthropoids, haplorrhines, strepsirrhines, and great apes. It discusses threats to primate biodiversity and extinction of some species