from his night bed, yawns in the early morning. The Sinsiba swamp, frequently visited by M-group chimpanzees. Back cover: A juvenile female, Xantip, watches her mother, Xtina, removing a sand flea from her toe. DVDs All photos on the DVD disks and the indexes in the DVDs were taken at Mahale by Koichiro Zamma. Printed on acid-free paper Springer is part of Springer Science+Business Media Preface Where We Stand Field workersscientists of animal behavior in naturehave long been fascinated by wild chimpanzees. A person who once has studied wild chimpanzees will be eager to observe them again. A person who has studied them twice will make every effort to continue the study, unless prevented from doing so. In short, behavioral primatology is addictive! Many people, among them Jane