Short answers, pulled from the story.
The earliest known primate Purgatorius emerged approximately 66 million years ago in North America. This small shrew-like creature lived during the Early Paleocene following the dinosaur extinction event.
Primates possess large domed craniums that protect enlarged brains and forward-facing eyes that provide binocular vision. Their hands feature five digits with sensitive pads and opposable thumbs that enable precise grasping and climbing.
Primate social systems range from solitary living to large multi-male multi-female groups based on female or male transfer patterns. Examples include female transfer systems in chimpanzees and monogamous pair bonds in indris and gibbons.
Jane Goodall first observed tool use in wild chimpanzees in 1960 when she saw a chimpanzee poke grass into a termite mound. This discovery challenged the belief that only humans manufactured and used tools.
Spain became the first country in the world to recognize the rights of some non-human primates in June 2008. Its parliament urged compliance with recommendations to stop using chimpanzees orangutans and gorillas for animal experiments.
About 60% of primate species are threatened with extinction due to habitat loss and hunting. Madagascar has experienced the greatest recent extinction with at least eight classes and fifteen larger species disappearing since human settlement 1,500 years ago.