Short answers, pulled from the story.
Scientists trace the primate lineage back to a boundary between geological periods approximately 65 million years ago during the Cretaceous Paleogene event. A small mammal named Purgatorius lived in North America around 66 million years ago representing one of the earliest possible proto-primates.
Primates generally display five digits on each limb with most species featuring keratin fingernails rather than claws. Binocular vision allowed them to judge distances accurately while moving through trees and opposable thumbs enabled better grasping of branches.
Chimpanzees form fission-fusion societies where the main group splits during the day and reunite at night to sleep together as a single unit. Ring-tailed lemurs utilize male transfer systems where females remain in natal groups while indri tarsiers and gibbons practice monogamous pair bonds.
Carl Linnaeus established Order Primates in 1758 within Systema Naturae including genera Homo Simia Lemur and Vespertilio. Modern classifications identify only monophyletic groupings including all descendants of a common ancestor.
Non-human primates primarily inhabit tropical latitudes across Africa Asia and the Americas. The black snub-nosed monkey lives at altitudes of 4,700 meters within the Hengduan Mountains while mountain gorillas cross the Virunga Mountains at elevations of 4,200 meters.
The International Union for Conservation of Nature lists more than a third of primates as critically endangered or vulnerable with about 60% of primate species facing extinction threats. Large-scale clearing for agriculture destroys these habitats and Indonesia lost 1,000 Sumatran orangutans per year between 1998 and 1999 alone.