PRIMATE DIVERSITY

The stars of our show are Barbary macaques, chacma baboons, and Guinea baboons. Before I provide a more detailed description of these species, a few notes on the varied appearances and habits of primates in general are called for. The Primate order is marked by an extraordinary diversity of physical form, lifestyle, and social organization. The spectrum runs from the solitary aye-aye, a nocturnal lemur of Madagascar that taps for insects under tree bark with its long and slender middle finger, to South American squirrel monkeys living in large colonies, to harems of gorillas, whose adult males can reach a size of four hundred pounds.

Primates originated roughly eighty million years ago. The nearest living relatives of ancestral primates are the Philippine flying lemur and the Southeast Asian tree shrew, both of which give a sense of what life might have been like for the earliest primate species. Today the Primate order comprises two main lines. First, there are the Strepsirhini, including the galagos (bush babies), pottos, lorises, and Madagascar lemurs. A well-known example is the ring-tailed lemur with its distinctive black-and-white ringed tail. The second group is the Haplorhini, which includes tarsiers, small nocturnal primates of Southeast Asian rain forests, and true simians. The true simians appeared fifty to thirty-six million years ago and comprise New World and Old World monkeys. The latter group includes tailed Old World monkeys, small apes such as gibbons, and the great apes — that is, orangutans, gorillas, chimpanzees, bonobos, and humans.

Among tailed Old World monkeys are the baboons, which I describe in greater detail below, and macaques such as the rhesus monkey, Barbary macaque, and Japanese macaque. Japanese macaques are especially famous for, and frequently photographed enjoying, their snow-encrusted hot spring baths. The guenons belong to this taxonomic group as well. One species in this group, the vervet monkey, has played a particularly important role in research on the communication of primates, and I will return to them in the third part of the book. In addition, the tailed Old World monkeys include colobine monkeys, prominent examples of which are the Asian Hanuman langurs and the black-and-white colobus monkeys of Africa with their showy and magnificent coats.

BARBARY MACAQUES: MODEL MONKEYS

I have studied Barbary macaques for many years, but I hadn't originally planned to do so. I had intended to become a marine biologist. After finishing my studies at the Free University of Berlin and the University of Glasgow, I was ready to begin doctoral work at the Sea Mammal Research Unit of Cambridge University. My final requirement was a course in behavioral biology. This took me to Rocamadour in southwestern France to investigate the social behavior of Barbary macaques at Le Forêt des Singes. Kurt Hammerschmidt, Henrike Hultsch, and Dietmar Todt, who later became my doctoral advisor, directed this fieldwork. The monkeys here, cavorting energetically around the park, gave me far greater inspiration than seals sprawling and loafing on a sea coast. Kurt is my best friend, and we continue to collaborate today as we did back then to shed light on the evolution of communication.

La Forêt des Singes — like the Trentham Monkey Forest in Staffordshire, England, or Monkey Mountain near Lake Constance in Germany — is mainly a tourist attraction. Visitors can stroll along established paths in the reserve and view the monkeys up close. But these parks are also well suited for scientific research and education. At Rocamadour, roughly 150 animals roam freely in three groups over an area of twenty hectares. They are given food and receive annual medical examinations, and live under no threat from predators — it is truly a monkey paradise. As Kurt observed: "The monkeys would happily visit their native wilderness, but they would be on the airplane the instant it headed back home." Hormonal contraception keeps the monkeys' birth rate in check. Despite these benefits for the monkeys, studies of captive animals are limited in the sort of questions they can reasonably pose. For example: Which male has the greatest mating success? Or: How much time must the animals spend in their daily quest for food? These are questions for which animals in captivity can provide no meaningful answers. On the other hand, because they are accustomed to humans and readily participate in non-intrusive experiments, such captive animals are ideal for studies of communication and intelligence.

Barbary macaques are the only macaques found in Africa, specifically in the forests and mountains of the middle and high Atlas, the mountainous Rif region of Morocco, and Kabylia in Algeria. There is a small population in Gibraltar as well. All other macaques are indigenous to Asia. Through evolution in harsh climates, the Barbary macaque has lost its tail, and for some time this led them to be classified with apes. In fact, the tail hasn't completely disappeared, as a small stub still remains. Over the cold winter months, they insulate themselves with a thick coat of fur. Autumn is mating season, and after a six-month gestation period, newborns arrive in the spring. Births usually happen in the evening or at night, when the danger of predators is minimal. In contrast to the brownish-yellow color of the adults, newborns have a pitch-black coat and pink faces and hands. A distinctive newborn coat is a common feature of many monkey species. Baboon infants are also black, except for those of the little-studied Kinda baboon, which are born with white fur.

The baby monkey spends the first week of its life clinging to its mother's belly. It grasps its mother's fur tightly with its hands and feet. If it lacks strength to hang on, the mother supports the baby with her free hand. After a few weeks, the baby is shifted to its mother's back. Among the tailless Barbary macaques, infants take a jockey position on the shoulders of the adult. Baboon babies, once a little bit older, can sit comfortably upright on the mother's back, leaning against her raised tail. But in Barbary macaques, mothers are not the only ones who care for and transport the young. More than in any other macaque species, male Barbary macaques express great interest in the little ones. Males frequently take the baby from its mother soon after birth and tote it around....