EAST AFRICA'S LESSER KNOWN PRIMATES HAVE CONTRIBUTED SIGNIFICANTLY TO OUR UNDERSTANDING OF HUMAN BEHAVIOR
Scientific field research on East Africa’s primates has greatly contributed to their conservation. Consequently, their continued existence in the wild has led to many amazing revelations, valuable insights and tantalizing clues about not only human biological evolution but also the origins and development of our perplexing behavior.
Let’s be honest, chimpanzees, mountain gorillas and even the somewhat still mysterious bonobo continue to capture the public’s imagination far more often than the uncouth and far less cuddly baboon. Chimps and mountain gorillas will be eternally connected to the pioneering and legendary primate ethologists George Schaller, Jane Goodall and Diane Fossey; while our bonobo cousins evokes sexual liberation at its sexiest in the animal kingdom (.
In spite of perceptions and histories, East Africa’s lesser known primates such as baboons have contributed significantly to our understanding of human behavior.
Take the issue of stress. In humans, stress has been known to lead to or exacerbate heart attacks, strokes, cancer and Alzheimer’s disease. The animal kingdom, of which we are part and parcel, exhibit numerous instances of episodic stress.
Robert Morris Sapolsky, the American professor of biology and neurology at Stanford University, USA has studied the social behaviors of Kenya’s baboon populations, primates with no predators that experience environmental and social stress sources like humans. For almost a generation, starting from the late 1970’s to the early 1990’s, Sapolsky observed the same group of baboons, spending eight to ten hours daily for approximately four months each year recording their behavior.
From Sapolsky's wildlife studies in east Africa we have learned that for many wild species, stress is generally episodic (e.g., running away from a lion), while for humans, stress is often chronic (e.g., worrying about losing your job or a cheating spouse). Therefore, many wild animals are less susceptible than humans to chronic stress-related disorders such as ulcers and hypertension.
However, chronic stress does occurs in some social primates studies such as those of Sapolsky’s baboons for individuals on the lower side of the social dominance hierarchy. Sapolsky has come to the conclusion that humans develop such diseases partly because our bodies aren't designed for the constant stresses of a modern-day life--like sitting in daily traffic jams or growing up in poverty. Rather, they seem more built for the kind of short-term stress faced by a zebra--like outrunning a lion.
Another case is of Ethiopian monkeys and grooming behavior. Grooming behavior in primates, that is cleaning and maintaining body function and hygiene of one individual by another, was previously thought to confirm what is known as the “Hygiene Hypothesis”- grooming for the sake of cleanliness.
However, field studies of Ethiopian primates by Professor Robin Dunbar of the University of Oxford, UK have debunked such beliefs. Dunbar spent the first two decades of his life growing up in northern Tanzania’s Tanga Province and for over a decade, conducted field studies of various baboon populations in the Rift Valley. Among the primate groups he has studied includes the Gelada (Theropithecus gelada) in the Simen Mountains and Colobus monkeys in the Ethiopian highlands and Rift Valley (he would also spend time studying vervet monkeys and other baboon species on the other side of the African continent in Senegal).
Dunbar’s focused on sociality and social groups. More specifically, he examined grooming behavior and concluded that it is an important aspect of social behavior and not simply for the sake of cleanliness as was earlier thought.
“Traditionally, we have always viewed social grooming as a form of hygiene,” says Dunbar. “Indeed, it is obvious that animals remove bits of vegetation and scabs (never fleas, because wild monkeys don’t have fleas) from the fur of the individual they are grooming. But gelada spend several hours each day engaged in grooming, and after spending many thousands of hours watching them persuaded me that it was actually all about social bonding.”
Take the case for the theory of human domestication, the notion that our docility, as compared to other animal species and indeed our hominid ancestors, were the result of our reduced reactive aggression and friendliness. Homo sapiens, along with bonobos (and perhaps a host of other species including the Western chimpanzees, Kinda baboons and perhaps the Asian elephant), for example, are suspected by some scientists as to have undergone a “Domestication Syndrome” during the course of our biological evolution in the wild.
(The Domestication Syndrome are a series of biological and behavioral traits such as a reduction in body size, docility and changes in bone structure to name but a few).
One way researchers can explore this unique phenomenon is by looking to our distant and not-so distant primate relatives in the wild.
Take the Zanzibar Red Colobus Monkey (Piliocolobus kirkii), for example, now classified as an endangered species. Their habitats are exclusive to the main islands of the Zanzibar archipelago, Unguja and Pemba, about twenty to thirty kilometres off the coast of Tanzania (Pemba has been separated from the African continent for a million years or more. Molecular data indicate that the Zanzibar Red Colobus as a species, is about 600,000 years old, suggesting that it evolved there not long after Pemba became an island. The species looks strikingly different from all the other Red Colobus monkeys on the African continent, of which some sixteen species have been described).
Some scientists believe that the Zanzibar Red Colobus monkey, currently the flagship species for conservation in Zanzibar, represents one of those rare species that might have been domesticated in the wild (African bonobos and Asian elephants are also suspected to have been wild domesticates).
Another clue that hints at the self-domestication of the Zanzibar Red Colobus monkey is that they are also paedomorphic-meaning that adults retain the juvenile characteristics of related species. For example, among the Ugandan Red Colobus monkeys, a pink outline around their mouths is seen only in infants less than a few months old; yet that same pink shape is retained throughout the lives of the Zanzibar species. In addition, the shape and size of the whole skull are also paedomorphic including large eyes, small face and a relatively small brain case.
Such important scientific discoveries and insights would hardly have been possible if Kenyan and Ethiopian primates were driven to extinction. But like so much of the Earth’s biodiversity today, a substantial number of Africa’s primates are among the one million species that are already facing extinction within decades says experts (mainland Africa is said to have 111 species of primates while the island of Madagascar has an astonishing 103 primate species).
In 2016, for example, during the International Union for the Conservation of Nature (IUCN) SSC Primate Specialist Group, African Primates Red List Assessment Workshop held that April in Rome, Italy, experts assessed the conservation status of African primates and discovered to their astonishment that 1000 out of 179 taxa (a group of one or more populations of an organism or organisms seen by taxonomists to form a unit )were classified as Threatened, with 35 Endangered and 15 Critically Endangered.
Sadly, external threats to such species are numerous and rising. Primate habitats in mainland Africa are being destroyed daily as the process of rapid and widespread industry-driven deforestation due to global market demands for products such as palm oil, natural rubber and tropical hardwoods and food crops like soya beans and rice.
Armed conflict and prolonged political instability in sub-Saharan Africa is a huge threat. An extreme case is the blowback from the 1994 genocide in Rwanda, which among other consequences, caused hundreds of thousands of refugees to flee to neighboring eastern Democratic Republic of Congo (DRC). This not only led to civil war a few years later but it also caused massive deforestation of primate habitats.
It’s estimated that by 2035, global demand for oil and gas is projected to increase by more than 30% and 53% respectively, and primate rich areas will be adversely affected. In addition, the construction of conventional dams for generating electricity to attract energy intensive industry and stimulate local productivity in the world’s most bio-diverse river basins including the DRC.
The dramatic rate of population extinctions and population decline due mainly to the human activities mentioned above including unsustainable hunting, urban development and habitat degradation due to global climate change frequently leads to a decrease in genetic diversity. Populations with low genetic diversity have limited capacity to adapt to fast changing environments, display lower fertility and are prone to infectious diseases.
Human-primate conflict due to primates feeding on crops remains a persistent problem and is likely to increase say experts because primate-suitable habitats are being converted into agricultural fields or gardens in response to local and global market demands.
“Where human and non-human primates come into more severe conflict due to crop raiding, culturally and economically appropriate management interventions can litigate the impact,” says Alejandro Estrada and colleagues authors of “IMPENDING EXTINCTION CRISIS OF THE WORLD’S PRIMATES: WHY PRIMATES MATTER.”
And yet, primates are important pollinators that are crucial not only to human diets (fruits for example) but their very own existence in forest habitats. Numerous primates are highly frugivorous. They also consume various flowers, seeds, gums and, leaves. And their relatively large size enables them to disperse small and large seeds over long distances enhancing forest regenerating.
(According to a study done by Irene Kone, the current African Primatological Society president, and colleagues in a 2008 report on primate seed dispersal, found that 42% of plants whose seeds are dispersed by primates in Uganda have economic and cultural uses to local communities there).
Primates not only significant contributors to scientific field research, the environment and our own aesthetic sensibilities, but they also play key roles in our cultural and social existence Many primates are important players in ecosystem dynamics and sustainability, and are central figures in local and regional traditional knowledge, folklore, history, and even economies.