Fossils show that howler monkey ancestors were eating leaves 13 million years ago, shaping body size and evolution.

An extinct relative of the howler monkey may have been the first leaf-eating primate in South and Central America ...

Thirteen million years ago, a group of medium-sized monkeys known for guarding their territory among the treetops with fearsome "howls" started doing something new. These monkeys, among the oldest ...

Kay, who has collected fossils of monkeys in South America since 1981, has worked with others in peripheral Amazon areas such as Chile and Argentina. By studying fossils from there and piecing ...

Cover -- Contents -- List of Illustrations -- Preface -- CHAPTER 1. What Is a New World Monkey? -- What is a monkey? -- What is a platyrrhine? -- Platyrrhines and catarrhines -- Platyrrhine taxonomy - ...