Primate Behavior Studies

Ryan J Trubits. 21st Century Anthropology: A Reference Handbook. Editor: H James Birx. Volume 1. Thousand Oaks, CA: Sage Reference, 2010.

Our species’ existence is an enigma that intrigues both scientists and the average human. The reason that we are even able to scratch the surface about this complex question is due to our ability to think critically, maintain culture, and articulate in a manner that has allowed other humans to understand. Humans are able to achieve success based on the ability to express their thoughts in written language, making use of semiotic systems. Scholars for the past 2 centuries have laid the bedrock of knowledge about our close biological and behavioral ties to the primates of this world. This evidence has provided the scientific community and the average human being an understanding of primate behavior as well as the opportunity for future advances. Despite their understanding of the primates, there are many individuals in our world who are still not convinced that humankind spawned from a fossil apelike form. Even so, it is hard to deny organic evolution as a convincing scientific theory. Humans cannot be the only exception to a theory that applies to the emergence of all other species on this planet.

Aristotle was the first of many naturalists to inquire about human existence. For centuries, Aristotle’s ideas of a static nature were the doctrine, despite an ever-changing world. Aristotle believed that species are eternally fixed on this planet. This claim rests on his belief that those species that are living on this plant at this moment have always been here and will always be living on earth. Many naturalists attempted to prove that Aristotle’s claims were outdated and dogmatized, but most failed to prove to the masses that the Aristotelian and later Christian view of life was wrong. Charles Darwin, the “father of evolution,” is one of the greatest naturalists to have lived. His comprehensive view of organic evolution provided the scientific world with a theory that incorporated not only biology but also geology, paleontology, and anthropology. His empirical arguments challenged old dogmatic ideas that spanned back to the insights of the ancient Greek philosophers.

When Darwin (2007) made his voyage on the HMS Beagle, he discovered that organisms that live in different environments acquire certain physical traits and behavioral patterns to adapt and survive. He also came across the idea that if identical species are isolated for long periods from one another, then these identical species will eventually radiate into different varieties and perhaps, given enough time, even into new species. Darwin extended this evolutionary framework to also include our own species, stating that human fossil remains would be found in rock strata and that these specimens would help scientists connect our lineage to the two living pongids on this planet. This idea was known as the pithecometra hypothesis, first presented by Thomas Huxley and Ernst Haeckel. This hypothesis argued the idea that our species is closer to the great apes or pongids (orangutan, gorilla, and chimpanzee) than they are to the lesser apes (gibbon and siamang). While Darwin was correct about the fossil evidence, today we have discovered a total of four living pongids (which now includes the bonobo), which are all arguably our closest living relatives.

The discovery of the DNA molecule in 1953 by James Watson and Francis Crick helped open the world’s eyes to the scientific truth of organic evolution. The molecular evidence that was discovered has shown that humans are biologically closer to the pongids than Huxley of England, Haeckel of Germany, or even Darwin himself could have imagined in the 19th century. These pioneers in human evolution studies had sparked interest around the world, and their influence contributed to the emergence of the discipline of anthropology. The theory that anthropologists follow in their search for knowledge about our past is based on the ideas of evolutionary thought. Many of our speculations may be incorrect, but the truth is that the fossil and artifact evidence found in the rock strata of our planet provides us with the opportunity to pose questions in a logical manner.

Anthropology covers many areas of science such as biology, archaeology, societies and cultures, linguistics, and applied anthropology. The study of primatology, while being a specific focus in biological anthropology, is itself comprehensive in that it attempts to compare and contrast both the similarities and differences in the human species with the other living primates on this planet. In the four pongids (orangutans, gorillas, chimpanzees, and bonobos), we have a window into our past. These complex and self-aware species are the only creatures on this planet, besides humans, which are able to think critically above the rest of the animal kingdom. In our modern world, we have obtained a significant amount of empirical evidence about our biological similarities to the other primates on this earth. These findings have allowed anthropologists to make substantial claims about our behavioral similarities to the other primates.

Studying the behavior of our closest living ancestors is important to advance anthropology because with this information, we can attempt to understand and appreciate how our fossil ancestors developed into the complex human creature of today. Unfortunately, the four pongids and the two hylobates are facing extinction. This is largely due to the environmental changes and human interventions they are trying to endure. At this time, it is crucial for scientists to study these primate species. To truly understand our complex relatives, we must be able to do extensive research on wild apes in their natural habitats. While research in zoos and labs allow scientists to determine these species’ intelligence and natural behavior, the only place where we can understand the life processes of these wild organisms in a nonintrusive matter is in their wild habitats.

What is the proof that we actually split from the pongids? While our species did not split from one of the living pongids, it is known that our existence arose from the time period that gave rise to the Dryopithecinae complex of fossil apelike species. During the Miocene epoch, hominids emerged in many different varieties. By the end of the Pliocene epoch, around 3 million years ago, the environment changed. As a result of this climate change, the tropical jungles of Africa started to vanish causing scattered open woodlands and grassy savannas. This caused a rift in the way fossil apes lived and the way fossil hominids lived. Some species remained arboreal (dryopithecines) while others become terrestrial (kenyapithecines). Fossil evidence demonstrates that the split happened in the Pliocene period, roughly 6 million years ago. Those species that were able to adapt and survive as terrestrial forms (kenyapithecines) evolved to become our more recent ancestors. Bipedality is the trait that first separated the hominid-like hominoids from the pongidlike hominoids. Later developments such as toolmaking, articulate speech, and a complex brain emerged in hominids during the last 3 million years. The living pongids are those great ape species that remained in the rain forests of the Eastern Hemisphere. In this long evolutionary experiment, only those species that were able to adapt to their ever-changing environments survived and reproduced.

Emergence of Primate Behavior Studies

The ability to think critically in terms of science and reason is what separates humans from the rest of the organisms on this planet. Our large cranial capacity and specialized brain have given us the ability to trace our historical lineage. While our species is by far more advanced in many functions of the brain, it is remarkable to see the striking similarities to us that the great apes and hylobates demonstrate. Evidence in behavioral studies clearly shows that we are not the only species to show the ability to think abstractly and articulate our emotions. Scientists accept the fact that we differ only in degree rather than in kind from nonhuman primates. We must not forget to study these species from an objective perspective, not form a bias that humans are far superior to their primate counterparts.

How primate behavior became of interest is a relatively new focus, only originating in the 1960s. This does not mean that there were not studies before this time. Research studies were carried out from 1800 to 1960 and the results analyzed but not with the rigorous discipline that is seen in the 20th and 21st centuries. The study of primates was in many cases secondary to the general mission of these studies. Some early naturalists avoided the behavior studies of wild apes in their natural habitats because these researchers accepted preconceived notions of the large primates, especially ideas about the “violent” gorillas. The fear that these savage creatures would cause harm to individuals set back intensive research studies in Africa.

The first major and groundbreaking study was not in Africa but in the New World, by Raymond Carpenter (1964), who studied the Howler monkeys and later the gibbons in Asia during the 1930s. One may claim this was prior to the 1960s, and they would be correct. But the progress made by Carpenter would be forgotten until after World War II. Primate field research was not a priority when the world was at war. Carpenter and other rising anthropologists, such as Louis Leakey in the 1950s, paved the way for future researchers and also provided an opportunity for individuals to actually go and study wild primate species in their natural habitats. The passion, which was missing from past studies, was instilled into a new generation of scientists who strove to further our understanding of humans by studying the nonhuman primates of our world. Through extensive investigation and comprehensive research on these close primate relatives, scientists hoped to open doors into our past. The 1970s and 1980s were a period in primate behavioral studies when research was done from a quantitative viewpoint. The goal of these missions was to obtain as much information as possible about the primate species of our planet. However, there has been a shift in emphasis from quantitative to qualitative studies, which forces scientists to refine their research methods. While it is important to learn the scientific specifics about a particular species, we must not forget that comprehensive studies should not be abandoned without constantly revisiting the main facts about a species, lest we dogmatize facts about our closest relatives. The more interpretations we have about a subject, the more valid our generalizations will be. While not intentionally disposing quantitative studies, scientists in many cases have been pressured by both government and private organizations to stray away from large ethological studies because they are not being funded. This can be seen even most recently in the rediscovery of the pygmy tarsier (Tarsius pumilus) of Indonesia. This species was believed to be extinct in the 1920s, but scientists fortunately discovered that this species still exists.

My argument is that we cannot allow for the slow removal of large comprehensive studies, especially when we have not truly learned everything there is to know about each species. In the case of the pygmy tarsier, we did not even know that it still existed. The truth is that our closest living species are vanishing before our eyes. If we do not obtain as much information as possible now and take serious steps to save primate species, then they could eventually disappear forever.

Prosimians

To truly understand what are primates, one must understand the criteria that we share with the other species of this planet. The morphological attributes that taxonomists use to determine what is a primate are ones that set it above and beyond other mammals. Species in this group are ones with grasping hands and feet, larger brains, shorter jaws, and a flat face in comparison to other living mammals on earth. The eyes of these organisms are close together and on the front of their faces; these species also have digits with nails rather than claws.

The two subgroups of primates are the Prosimii and Anthropoidea. Prosimian means “premonkey,” and the prosimians of today are believed to be living representations of the early arboreal primates. Prosimians are located in the rain forests of Africa and south Asia.

The earliest and least complex primates are represented several living forms, as the tree shrew, loris, lemur, indri, and tarsier. Tree shrews are found in India, Burma, Sumatra, Java, and the Philippines. The tree shrew is a solitary and asocial creature by nature; the tree shrew will be seen in pairs only in time of mating, but this is the only period where pair-bonding is present. Males are aggressive and will defend their territory. They do so by marking trees with a fluid excreted from the chest.

Prosimians are arboreal and insectivorous, and many taxonomists still classify them with the insectivores. But their complex brain, emphasis on vision rather than smell, and digital flexibility place them in the higher suborder Prosimii. Many believe that the tree shrew is a biological and social link between insectivores and the more evolved prosimians.

Lorisformes are located in Africa and Asia; they are characterized for their nocturnal lifestyles and for dwelling in trees. Lorisformes are found normally as individuals or in pairs. Grooming plays a large role in their lives, and it is seen as a form of communication and the creating of relationships between individuals. Lorises feed mostly on insects and supplement their diet with a source of fruits. All members of this subfamily are nocturnal, and they hunt their prey by proceeding quadrupedally through the trees.

The Lemuriformes of Madagascar and the Comoro Islands in the Indian Ocean are composed of lemurs, the aye-aye, and the indri. The species of the Lemuriformes vary in size from the tiny mouse lemur to the largest species, the ring-tailed lemur. Smaller species are nocturnal in behavior, but the larger members of this family are diurnal. These groups, depending on the species, live as individuals or in social groups. These prosimians, especially the lemurs of Madagascar, have prospered on the island due to its being an environment with little to no predators. The only species who threaten this arboreal creature are the hawks, eagles, and humans, who have placed the lemur on the endangered species list because we have infringed on their environment with logging.

Lemurs, due to natural selection, have favored vision over smell and have also created tight social groups to survive against predators. This can be compared to humans in the sense that we adapted to a lifestyle that has been dependent on sight and working together to survive in our ever-changing world. Lemurs are a very social group that play and groom one another; lemurs live in groups of about 24 individuals. They form close relationships with other lemurs due to this nonverbal communication with one another. Like humans, lemurs share a sense of pride in protecting their territory but do so by marking their territory. Lemurs mark their surroundings by urinating or releasing hormones from a gland in the forearm and inner side of the upper arm; they rub their scents onto trees by scratching. In lemur society, males have a hierarchy that is determined by which males are able to distinguish themselves from the others in the form of vocalization.

Tarsiers are found in Borneo, Sumatra, and parts of the Philippines. They are a small species with very specialized traits. Its large eyes and large ears allow for an ideal adaptation to nocturnal behavior. The Tarsiiformes are usually considered the highest form of Prosimians because of the emphasis on vision, the flexibility in its digits, and also the specialization in the brain found in the tarsiers. Tarsiers are unable to rotate their eyes, but they compensate for this by being able to rotate their head 180 degrees. The species is dependent on being able to leap from tree to tree in search of insects and small vertebrates for its strictly carnivorous diet.

New World Monkeys

The anthropoids of the world consist of monkeys, apes, and humans; this grouping is supported by the close genetic similarities among the anthropoid species, as well as the fossil evidence found in China in the rock strata of the mid-Eocene, which is about 45 million years old. This fossil evidence led people to support the separation of two subgroups of primates, the prosimians and the anthropoids. However, the fossil evidence of some anthropoids is anatomically similar to the modern tarsiers, which allows science to claim that the tarsier is the most related prosimian to the anthropoids of the planet.

The fossil record proves that 40 million years ago, both New World monkeys and Old World monkeys shared a similar genetic relative. By this time, the planet had already shifted into the current geological makeup of our modern world. The science community is still unaware of how the forming of New World monkeys occurred, but it is believed that New World monkeys evolved in the Old World and reached South America via rafting on logs. After this time, the New World monkeys of our planet evolved independently from the Old World monkeys. They now live in the tropical forests of the Western Hemisphere. New World monkeys are known as platyrrhines, a term that comes from the characterization of each species having a broad, flat nose. Due to the geographic isolation of the two groups of monkeys, they diverged in characteristics but in similar ways because of their common evolutionary ancestry.

New World monkeys are found in Central and South America. The species are all classified under the super-family of Callitrichidae, which is broken up into two sub-families (Callithricidae and Cebidae). Dependency on the trees as a form of protection, the adaptation of a prehensile tail, and dermal ridges on their tails have allowed these species to live for the most part without fear of predators.

The Callitrichidae includes marmosets and tamarins. Marmosets are found only in southern areas around the Amazon River. Tamarins are found only in areas north and west of the Amazon River. Marmosets inhabit most types of forests. They feed on insects and fruit. Marmosets move quadrupedally, leaping and climbing from tree to tree. This New World monkey lives in family units consisting of a mother, father, and offspring. The major anatomical differences between the two species (the marmosets and the tamarins) is the structural makeup of the lower jaw. Marmosets have a V-shaped mouth, while tamarins have a U-shaped mouth. Tarmarins are dependent on a stable diet of fruit, with insects being a supplement, and like their counterparts live in family groups (mother, father, and off-spring) that move together from place to place.

The Cebidae group, the larger of these two families, is a subfamily in which most members are diurnal. This family consists of the capuchins, who live in very social communities of 10 to 30 members. They feed on whatever is available to them such as fruit, flowers, leaves, invertebrates, and birds.

The most extensive study performed to this day was done by C. R. Carpenter (1964), who did field studies on the free-ranging red howler monkey. This isolated primate was ideal for studies because it helped not only the study of this primate but also the study of interactions between other groups, as well as the howler’s own ecological territory. His study helped uncover information about the size, movements, age and sex distribution, sexual behavior, and forms of communication. Howlers belong to a subfamily of the Cebidae family called the Alouattinae, which has six species that cover a region from Mexico to Argentina.

Howler monkeys, the largest New World monkey, can reach 6 feet in size from nose to tail. They are entirely arboreal, living in the highest branches of the tallest trees. They travel in small bands of 10 individuals. Howlers have good color vision but a poor sense of smell. They eat leaves, fruits, and flowers. The adult male howlers bellow a roar, which is possible because of the bone at the base of their tongue known as the hyoid bone. This hollow bone allows for a large powerful bellow. Bellowing may be used to express an emotion or defend a territory. Adult males gather for social roaring in the early morning or early evening; their howling carries through the jungle for almost 2 miles.

Sexual dimorphism is very present in all six howler species; females are three quarters the size of males. Howler monkeys are also dichromic as males and females have different color coats. The howler monkey, in comparison to other New World monkeys, does not venture far from its territory. A howler society consists of a multimale group, which ranges in size from just 3 to 20 members. It covers a small radius of land. The howler diet is primarily of leaves, so the howler is a slow moving monkey.

The spider monkey is a New World monkey. It is part of the Atelidae group and is structurally similar to the howler with a difference only in the size; the howler monkey is significantly larger. The spider monkey is a sexually monomorphic species, which means that males and females are almost identical in size. The only major difference between the sexes is the length in the canines of the males, which are longer. The long and narrow hands of the spider monkey allow it to move swiftly through the trees; this differs from the slow moving howler monkey. Like the howler monkey, the spider monkey has a long prehensile tail that is used like a fifth appendage. This tail shapes the behavior of the species, as it is used to make the balance and adaptability of an arboreal lifestyle possible.

Females play a dominant role in a spider monkey society. This species lives in groups of 15 to 25 members, making it a very social group. Females decide when the group will move from one place to the next, when they will search for food, and when the group eats. Unlike the howler monkey, who lives primarily on leaves, the spider monkey has a staple diet of fruit. Since ripe fruit is difficult to find, spider monkeys break up into small foraging groups of 2 to 8 individuals to reduce competition among members. The female leaders know where all the great feeding paths are, so they are more likely to receive the ripest fruit. Unlike most primate groups, spider monkeys do not really see a great importance in grooming. However, grooming is usually present in most of the primate species that live in a complex social group.

Old World Monkeys

The Old World monkeys of this planet are found in Africa, Europe, and Asia. These species of monkeys are roughly 30 million years removed from humans and the great apes. The superfamily in which these species are classified is known as the Cercopithecoidea and is divided into the two subfamilies of Colobinae and Ceropithecinae. The Old World monkeys are arboreal and terrestrial species that live off a diet of vegetation or fruits. The communities in which they live vary in size from 8 to 200 members.

The Colobinae are leaf-eating insectivorous monkeys that are represented by the colobus monkeys of Africa or the langurs of Asia. This species, in contrast to the cercopithecines, are vegetarian. Other factors that distinguish them from the adjacent subfamily are that they lack cheek pouches, and they have a complex digestive system, which divides their stomachs into multiple chambers. Unlike the terrestrial Cercopithecinae species, these species are dependent on living an arboreal lifestyle. They nourish themselves with fruits, leaves, and flowers. To collect food, a group forms a party to forage for these necessities. The group consists of a single dominate male and a number of females and their offspring.

Langurs, unlike the colobus monkeys, live in groups of one or more males with the company of females and their young. They go out and forage in groups to obtain food. The langurs are located in the regions from India to China and Southeast Asia. While the colobus monkey shows a behavior of using semibrachiation, langurs are very specialized in their hands, which allow them to move from tree to tree with precision. The fingers of the langur are very long, and its thumb is reduced in size to allow for an easy ability to cling to trees.

The Cercopithecinae include the baboons, mandrill, drill, galeda, macaques, and vervets. These species are found throughout Africa and parts of Asia. The species of this subgroup are both arboreal and terrestrial, compared to their counterparts, the arboreal Colobinae Old World monkeys.

Based on their well-adapted life on the grassy savannas, baboons are of special interest to anthropologists. The baboon is the largest of the Old World monkeys. The social behavior and structure of this Old World monkey has become of much interest. The baboons’ ability to live in large societies and cooperate to survive in an environment where they are the prey of many larger animals (cheetahs, lions, hyenas, hippos, leopards, water buffalo, and crocodile) is crucial to understanding the evolutionary past of early humans who lived in a similar climate and environment and faced the same obstacles. The recognition that the baboon is an intelligent species, not strictly relying on instinct, dates back to Charles Darwin. In the 18th century, prior to Darwin, it was believed that intelligence rested in the mind of humans who were able to separate their natural instinctive urges and live in a world of strictly rational thought. This was changed with Darwin’s claim that humans are like all animals that are able to learn from experiences as well as from instinctive ingrained memory. Darwin believed that instinct is a product of our evolution. Metaphysics is the understanding of existence. To understand how humans evolved into the species it is today, we must uncover fossil evidence to study our closest relatives so that we can envision how we once lived.

While Old World monkeys are roughly 30 million years removed from us, their social network is of major importance because it helps to point out the fact that before tool use and language, social networks must have formed first to promote the survival of species that were limited to smaller cranial capacities. Having large brains has many evolutionary risks. Complex brains need lots of caloric energy to run efficiently. As a result, to reduce the need for larger brains, other animals become specialized in specific skills and in specific brain tissue.

In central East Africa, olive baboons (Papop anubis) use their social skills to ban together to avoid becoming killed by other species. While collectively this allows for a better opportunity to survive, it also becomes difficult when resources are limited. The social order of a baboon society revolves around a static matrilineal and an unpredictable male social hierarchy. The dominant male is constantly threatened by new immigrant males and younger males, who challenge the alpha male with their larger and stronger physical makeup. As the alpha male, the leader must make decisions for the entire baboon colony, and he is allowed the first right to impregnate females that are in periods of ovulation. Maintaining a status of alpha male is difficult due to constant attempts by other males for this position. The average control of this position by one male rarely is longer than 7 to 8 months. To determine one’s dominance over another male, males challenge other males by chasing one another. Physical fights are rare to nonexistent. However, if males are unable to determine if one male is stronger than another, they display wahoo calls (loud, low-pitched calls) to indicate who is the strongest. Wahoo calls take a lot of energy, so many males become exhausted after the challenge. While the dominant male is provided the first chance to impregnate the female members of the group, he will not necessarily be successful in the monopolization of all the offspring of all the women. Alpha males achieve success through reproduction and also by the killing of infants that are not their own. Infanticide is not just a process done by baboons; it is performed by many species in the animal kingdom. Infanticide is a way for males to eliminate competition from the gene pool. Since alpha males have a period of only 8 months to monopolize the mating of an entire baboon society, males try to eliminate any infants that are not their offspring. Infanticide is a sexually selected trait that enhances a male’s fitness. Infanticide in the animal kingdom happens in primarily polygynous species where competition is intense and females are unable to organize and protect themselves from male attacks. Unlike females, males rarely live past 15 years because they are unable to live longer in such a stressful world. The constant threat of losing one’s alpha status is a constant risk as a male becomes older and fears that immigrant males will be able to enter a group and dominate.

Reproductive success and becoming the alpha male are the two most important instinctive goals of all males. While this attitude appears to be selfish, it is one of many variables that disturb the balance of a community. Grooming is another behavior that allows for communication and a sense of security. This practice is not only just a way to relieve stress within a group, but also a practical way to remove salt, dirt, and parasites from the skin of fellow baboons. Grooming is a large part of the social life of this Old World monkey; they spend over 4 hours a day grooming.

The nuclear family is nonexistent in baboon culture. Friendships and alliances between males and females are only for short amounts of time. These truces are a way of handling business. Females appreciate protection from outside immigrant males who may kill their children, and males are willing to protect these infants because they have a vested interest in protecting their offspring. Infants are completely dependent on their mothers for over a year. Female baboons’ aspirations are to protect their children and to live a long life. Unlike males, females are seen as a large social unit because females with genetic ties will protect each other. It is common for females to form ties outside of their genetic group; this is established through grooming. Matrilineal society is linear in which one family is dominant over all other natal groups. This hierarchy is transitive in which natal Group A is dominant over B, and natal Group A is dominant over C. The female hierarchy, unlike in males, is not dependent on being able to physically dominant other members of the society. Rank is determined by age (the youngest sister is the highest ranking of the family members), a baboon’s association with natal relatives, and alliances with other females. The female caste system is very rigid. While it is possible that one could fall from status, it is almost impossible to achieve alpha status overnight. Low-ranking females are unable to achieve higher status because the association of lower-ranking kin affects their status. Without the alliances of fellow kin, a female is unable to ever achieve higher status because she is unable to protect herself against other kin groups. A comparison to human social life is the belief that poor people have high stress in their lives because of low income, but the fact is that without a social support system, they are never comfortable because of the lack of control in their lives. When disputes happen between a higher and a lower female baboon, it is engrained in the inferior female that she will have to back down from the dispute. High-ranking females have a regal allure that is unquestioned by lower-ranking females. As a result, when a dispute ends, there is no direct reconciliation. One may ask how society ever functions if there is never a resolution to an argument. The answer is that other family members confront the victim of the aggressor. The reason higher-ranking families stay in power is their ability to remain unified. Unlike males, who are constantly trying to obtain alpha male status, females live a life that is less stressful when social movement is not present. It is equally stressful when they are going up or down on the social spectrum. The only true downside to being a lower-ranking female is the fact that protection of infanticide is lower because high-ranking males see no reason to protect socially weaker females. Protection is vital to a family’s ability to live a long life and allow for a safe environment for its offspring.

The reason that baboons are known for having an extensive social network is the fact that all baboons in a society must be able to adapt to ever-changing demographics. As scientists learn more about this species, they realize that baboons live traumatic lives, which have directly resulted in a short life span. With limited cranial capacity, baboons are unable to alter their environment to their needs. This sets humans and baboons apart. It affects not only the immune system of the baboon but also causes major damage to the mind of the baboon. In a life span, an individual must be constantly aware of its surroundings (such as births, deaths, immigrations, emigrations, sexual courtships, and fights). How is this physically possible? For baboons, it is an unconscious function. Baboons are able to determine social relationships and kinship ties based on the ability to recognize individuals in their group through smell and vocalization. While self-recognition is present in baboons and other Old World monkeys, it is difficult for scientists to prove that these species can empathize with other members of their community. Even though humans are more suited to perform this task, it seems the development of this function in our brains is grounded in symbolic language as articulate speech rather than merely in social observations. The baboons’ ability to unconsciously determine the rank of an individual is a skill that must have been favored by natural selection for this species. Baboons that are able to effectively determine their social network are able to live in a large, governed social structure. This allows for baboons to live on the open savannas where they are physically less dominant than other species. The ability to make quick judgments allows for a simplified method for running a social organization. Simplifying social life is a process that is unconscious and can be compared to humans when our species tries to make tasks easier by creating new methods or tools to allow our life to function more efficiently. The evolutionary history of baboons favored the social function, so baboons became more efficient at living in large groups. As stated before, bigger brains result in the need for more energy, and as a result, instead of bigger brains, the social specialization of the baboon species has resulted in a less solitary life, whereas a baboon with an individual lifestyle would be dependent only on its own ability. Having social skills is a trait that allows for baboons to survive not just in their harsh environment but also for being able to observe the unpredictable social world of baboon culture. In comparison to humans, the baboon is a very introverted species. Understanding the internal thoughts of an individual is difficult. Vocalization is limited to grunts that express a very general idea. This struggle to express information highlights the ability to observe the world as a necessity.

The day-to-day ability to plan for future events is not possible for a baboon. The brain of Old World monkeys is not as developed in comparison to the brain of pongids and humans. Baboons live in the moment, unable to sort information to help make their lives easier. Baboons are a diurnal species like humans. A baboon sleeps in the trees at night and hunts by day with an entire group. When traveling through the forest, baboons make loud noises to scare off predators. To achieve success in fighting off large animals like water buffalo, leopards, and hyenas, baboons mob up against the predator. Baboons are vegetarians, so fighting off large animals is only to prevent traumatic attacks.

The other Papio species of baboon (Papio hamadryas) is found in the deserts of northeastern Africa. Unlike the large groups of eastern Africa, the baboons of the desert are forced to live in small units because of the scarcity of food. Feeding units consist of a single alpha male and 1 to 4 females who also bring along their offspring. This baboon spends the night in large groups of hundreds of individuals on rock strata to protect themselves from larger predators, but during the day, a large group disperses into family units. A group forages with a single adult male accompanied by his females and their offspring. There is significant sexual dimorphism and sexual dichromatism in the baboons of East Africa. The adult male hamadryas baboon clearly distinguishes itself from its female counterparts. With large canines, caped hair, and a dominating size almost double that of females, males clearly have an upper hand at maintaining control in the baboon world.

Studying the Old World monkeys of Africa and southern Asia has provided a scientific insight on how protohominids and early hominids may have existed before the emergence of our own species. The ability of baboons to work with one another in communities led to their success in surviving on the unforgiving savannas.

Hylobates

Gibbons are members of the Hylobabtidae family. They are most notably known for their long arms and unique vocalization. Gibbons are very nimble in their arboreal setting, using their long slender fingers as hooks, allowing them to swing from tree branch to tree branch efficiently. The type of locomotion that hylobates perform is known as brachiation. Based on the anatomical ball and socket design, the gibbons’ locomotion style is an arm over arm movement. Gibbons are known as lesser apes in comparison to their counterparts, the pongids or great apes. While they share similar characteristics such as an absence of tails, broad chests, and an upright posture, the lesser apes are unlike the great apes due to having a smaller cranial capacity and body size. The Hylobatidae family consists of 11 species that are recognized. These species are divided into four subgenera based on their different characteristics.

Gibbons live in moist rain-forest-like settings, where they spend the majority of their time, living in the high canopy of the forest. This allows for hylobates to look over the entire forest, helping them to avoid conflict with larger predators like leopards and pythons that live less than 10 meters from the ground. This is another behavioral trait that separates hylobates from the great apes, as the great apes are more prone to a terrestrial life. The lesser apes of Southeast Asia are similar to monkeys anatomically in size and their dental makeup. However, they are also similar to the great apes because they do not have tails.

Their diet consists mainly of fruits but also includes leaves, flowers, and small invertebrates, such as bugs. Monogamy is present in gibbon behavior. It is believed to be an ingrained practice, due to the social need and time spent in raising offspring. Forming strong bonds with its mother or father plays a direct role in the health of gibbon offspring. If the male is not present to protect and provide resources for the family, the species would have never survived as long as it has. Around the age of 10 years, an off-spring leaves the comfort of its parents and ventures off to find a mate. Vocalization plays a pivotal role in the pair bonding of mates. Duets in the morning and evening between males and females allow for an understanding of the other ape before they meet. This form of communication is not only important for a baboon in meeting its future mate but also is important in the guarding of its territory. The species is able to perform these melodic sounds due to a throat sac that lies below the chin.

Due to the gibbon’s dependence on living in trees, researchers are still attempting to understand this hylobate. Since the species is isolated up in the canopies of the forest, it is difficult to understand the lives of this creature after the sun has set. The gibbon, unlike any other tree-dwelling ape, does not build a nest in the trees. This is due to the adaptation of its callused hindquarters.

The time is now right for scientists to uncover as much information about the gibbon species as possible. As the environment of these species becomes increasingly threatened by humans in the forms of logging and agriculture, the species are more and more at risk of extinction.

Pongids

Orangutans, known as the men of the forest, are seen as the most antisocial of the four pongids. While this species is more introverted, it does not mean that there is not much to learn about this behaviorally and genetically great ape similar to our own species. Researchers such as Birute Galdikas (1996, 2005) and even the pioneer of orangutan studies, the late Alfred Russel Wallace, claimed that this animal in its natural environment of Sumatra and Borneo is not challenged to outwit other animals on these secluded islands. The only true threat to this species is human intervention. Hunters steal infants and sell them on the black market or to zoos. Adult males, in response to these attempts to steal the babies, attack poachers and are killed as a result. Human intervention does not just stop there. Deforestation is also a part of the orangutan’s struggle for survival and reproduction. Logging companies use the precious timber of these islands for carpentry and use the leveled land for farming and/or ranching.

As stated before, the orangutan is a very introverted primate. The only ties that are shared between adult males and females are for procreation. Large males attempt to monopolize the gene pool of their area. They perform this by spreading their genes to as many females as physically possible. The reason it is impossible for this feat to occur is due to the size of an adult orangutan. They vary in size from 110 to 198 pounds, which makes it difficult to travel efficiently. While this task may be impossible, it does not stop the males from wanting to achieve this goal. Female orangutans have a slow reproductive cycle; the opportunity to conceive is only every 10 years. The long gestation period has its benefits and its drawbacks, as it gives the females the responsibility to choose the most suitable mate. But the survival rate of the species is dwindling because it takes so much time to conceive only one child.

Compassion is rare; it is displayed only between a mother and her offspring. While genetically 97% similar to the human species, orangutans are seen as not being our closet living relative. However, there are many who believe that anatomy and social behavior should be enough evidence to outweigh the DNA difference. The argument is somewhat valid due to the genetic difference. However, there are still many examples that show similarities to us such as intelligence. Orangutans understand the importance of protecting themselves from the elements. They do this by building huts for themselves. They create a nestlike structure with a roof to protect them from rain.

The prehistoric human’s diet was once similar to the pongid’s of our world. But due to environmental pressures, we changed our diet for a better opportunity for survival. An orangutan’s diet consists primarily of fruits, leaves, flowers, bark, honey, termites, bird eggs, insects, buds, shoots, and seeds. This diet can make it quite difficult for this pongid to survive because of the unpredictable occurrences that happen to the environment. When their environment is being deforested and the climate causes long spells of drought, hostility reigns over the islands. Since orangutans are antisocial, cooperation is not present. When resources are scarce, males fight over the resources. Orangutans obtain most of their caloric value from fruits, and it takes a lot of fruits to achieve their desired caloric intake.

While scientists believe that humans are not closest to the orangutan, there are alarming characteristics that prove otherwise. Like humans, orangutans are susceptible to human diseases like malaria and the common cold. Other remarkable physical characteristics that single out this great ape from the other pongids are its sexual dimorphism between males and females. Facial hair, cheek pads, long hair, and a throat sac (male traits) show the complexity between the male and female development. Humans show a large spectrum of diversity in their physical characteristics. This difference occasionally results in males and females being unable to show physical differences or result in a human being sterile. Male orangutans have this shared similarity, known as bimaturism. These males are unable to grow long hair and lack cheek pads or a throat sac, but surprisingly they are able to mate. Even though it is difficult for these males to attract the opposite sex, they are still able and willing to mate.

The debate about genetic similarities is always contradicted by unique similarities; scientists can make assumptions about the bonobo and chimpanzee because they are more extroverted pongids than the orangutans and gorillas. The gorilla is seen by scientists as the pongid with untapped potential to be our closest relative. It is hard to judge this large and peaceful species because scientists are still trying to study these primates within their remote locations.

The shy, gentle, curious gorilla is seen as a species that has the most potential for scientists to discover more about ourselves. The gorilla has shown proof of its ability to solve complex problems in tests performed in labs and zoos. However, in the isolated mountains of Rwanda and northern Congo, it is a different story. Like the orangutans, gorillas do not have predators that challenge their well-being for survival and reproduction. Without any animal forcing them to critically think about how to obtain the resources they need for survival, the gorilla does not show objective signs of great intelligence, and therefore, it is stereotyped as unintelligent. The gorilla is a more social creature in comparison to the orangutan. Gorillas groom and play with other members of their communities. These small societies in which they live are very important for the development of the members of the community. Male gorillas take pride in the protection of their territory from other predators. Mountain gorillas live in small groups of approximately 10 individuals. One silverback male gorilla rules over adult blackback males, adult females, and juveniles.

Males are the dominant figures in a gorilla society. The functions of the entire community revolve around the silverback male. Some extreme cases of inability to accomplish tasks occur when a silverback male dies. The entire group can dissolve because the female’s only bonding is between her child and significant other. As a result of this situation, females will leave to join other groups in order to mate. Mature silverbacks can weigh up to 450 pounds; unlike any other pongid, blackback gorilla males must assert themselves into a role in their group. When males reach a certain age, they are forced to decide if they are going to leave the group to start their own clan or remain as a part of their initial clan and hope the adult silverback will share his females. Leaving a group is difficult because it takes a long time to be accepted by another group— males may spend from months to years wandering in hopes of being accepted.

Like humans, gorillas are unique. All individuals have their own personality, distinct nose print, and voice pitch. This shy species, like humans, also appreciates its privacy. In cases of mating, males and females will find hideaways to share time alone. These intelligent creatures show signs of compassion toward one another. Dian Fossey (2000) depicted a moment from her long list of encounters where an elder male tickled a child with a flower and other moments at times when gorillas have encountered the death of loved ones. The first findings of the mountain gorilla, depicted first by George B. Schaller’s (1997, 2003) studies, helped eliminate the generalizations about this shy and timid species.

This gorilla was once known as a savage animal, but now we see the mountain gorilla as comparable to cattle. The diet of the gorilla is poor, forcing the species to live a slow, uneventful life. With a diet consisting of insects and grasses, the gorilla has no leisure time because it is constantly foraging for food. This type of diet is unknown to humans, who are primarily omnivorous, which allows us the best chance for survival. Diet is very important to the chimpanzee and is similar to that of humans. Scientists have much knowledge about this extroverted primate, and evidence suggests that this great ape is our closest living relative.

The knowledge that we have obtained about the chimpanzee can be credited primarily to Jane Goodall (1990, 2000). Influenced by the late Louis S. B. Leakey, Goodall has studied chimpanzees in the Gombe area of Africa for over 45 years. The research about the chimpanzee’s social interactions with others has shown the intelligence and the shocking acts that make the chimpanzee debatably the pongid most similar to Homo sapiens sapiens.

Unlike the gorillas and orangutans, chimpanzees are known for their tool usage and their ability to solve problems. This pongid has shown countless examples of its methods of outwitting its environment. Chimpanzees use twigs to extract termites from logs and pipelike sticks to hunt for fish and to extract honey from hives. Another intriguing behavior is the chimpanzee’s ability to use leaves as a sponge to soak up water from streams and puddles. While tool usage varies, there is evidence that proves that this great ape critically thinks to solve problems. These techniques are learned from an individual of the group and learned from others through observation. The most important development in a young infant chimpanzee’s life is the time spent with its mother.

Chimpanzees live in groups of 25 to 125 individuals. Chimpanzees in a society like humankind’s is very community oriented. Chimpanzees work together because everyone has a vested interest in survival and prosperity. The males of the community share a sense of pride toward their territory. This land has specific boundaries that are constantly being fought over for its resources. The borders are defended by males who fight against neighboring communities. It is important to the success of the chimpanzee groups that males become a cohesive unit “army” because it plays a direct role in the survival of the community. Males never leave their communities, which allows for this cohesive bonding among other male chimps. The males of a society are very social with one another. They spend lots of time grooming, hunting, and protecting their territory.

Females, on the other hand, are by far not as sociable as males. Females spend most of their time raising their off-spring, which is their primary goal in life. Outside of taking care of their children, females are solely interested in being around males. The female’s menstrual cycle, unlike the orangutan’s, is a 37-day cycle that every 9 to 10 days is evident by sexual swelling on the female’s hindquarters. This swelling is appealing to males. This pink football sized sac shows the sexual availability of the female. This swelling is believed to be an adaptation to promote reproductive success and also competition among males. The sac is the body’s physical reaction to the time when conception is optimum in an adult female. The membrane inflates from an increase in hormones. Scientists believe that females are the key to the success of the chimpanzee population because females hold the key to selecting the most fit among the males. Female chimps, like gorillas, are free to leave societies and join other groups; this is acceptable based on the fact that sexual swelling is a “passport” into other communities. This is not the case for males, which are tied to their community.

Territory, while not clearly marked, is one of the sole reasons for violence in chimpanzee society. Like humans, chimps are very emotional creatures; Jane Goodall (1990, 2000) has reported cannibalism and murder in chimp behavior. These brutal displays are shown when males stray from their group. As a result, males that stray away from a group are usually killed and eaten. Warfare between groups is never a battle of epic proportions. The only time groups will even attack is when they know they outnumber another group.

Chimpanzees, like humans, understand that territory expansion is important to increase their resources. Males see the importance of reproductive gain in finding new females. By extending their borders, they are able to take resources such as fruit trees, sources of water, and termite hills. Cooperation between chimpanzees is vital to achieve a successful hunt; most nonhuman primates do not eat vertebrates. Only a few higher primates, such as chimpanzees and humans, eat other mammals. Chimps prey on a variety of mammals of at least 35 known species. Of the prey that chimpanzees hunt, 80% is the red colobus monkey. Meat accounts only for 3% of their diet, though. Hunting is primarily a male role in society. Tracking for prey is a bonding experience that promotes cooperation among males. Having a large group improves the chances of success. The reason scientists think that the chimpanzees may be our closest living relative is due to our strikingly similar diets. Their diet is comparable to the diet of past hunters and gatherers.

On the other side of the Congo River, another extroverted species known as the bonobo is a species that is only now being studied. DNA analysis shows that we share over 98% of our genetic matter with both the chimpanzee and bonobo. This arboreal pongid found in central Africa is known for being less aggressive than its strikingly similar counterpart, the chimpanzee. The bonobo (Pan piniscus) forms a female-centered egalitarian society. Their social order is run by an adult alpha female. The extroverted bonobo is seen as one of the closer links to our existence. With its ability to use tools, stand erect most of the time, and express a wide range of emotions, this great ape makes a case for being the closest living relative to us. Primarily frugivorous, scientists believe that this harmonious species lives in peace. This is because the species’ environment has an abundance of vegetation, allowing them to live in large groups without fear of competition.

The discovery of this species was first documented by Belgian hunters, who brought back to Belgium their carcasses and skeletons from the Congo in the 1920s during the age of colonialism. Bonobos were first claimed to be a subspecies of the chimpanzee up until the 1980s. The distinction was finally made in 1982 by Harold Coolidge, an American anatomist, who claimed that the species was structurally different from the chimpanzee. The major anatomical differences between chimps and bonobos are that bonobos have a slender frame and bonobo males are only slightly larger than females. Both bonobo and chimpanzee males are more robust than females. From the neck up, bonobos resemble chimpanzees: Males are more robust than females, with larger canine teeth. From the neck down, bonobo males and females are almost identical. Due to isolation, these species eventually specialized to form the modern chimpanzee and bonobo. Chimpanzees, unlike the bonobos, live in an environment that is half savanna and half forest, while bonobos live strictly in a tropical rain forest climate.

Anatomical differences are not the only significant distinction between these two species. The social behavior of these two pongids are polar opposites. The first major study that helped shed light on these behavioral disparities was performed in the 1930s by Eduard Tratz and Heinz Heck at the Hellabrunn Zoo in Munich. Their template provided evidence of the major differences between the two great apes. The eight point behavioral study emphasizes sexual behavior, intensity of aggression, and vocal expression. This study was sadly disrupted when World War II broke out. This setback is just one of many in the search to understand this forgotten ape. The bonobo has been the most difficult ape to study for a multitude of factors—for example, the shy and timid species takes time to open up to humans. The successful studies at the Wamba site were due to the use of sugarcane to entice bonobos to approach and accept humans. The bonobos’ environment is another reason why this species is difficult to study. It lives in a thick and isolated rain forest, which covers 80% of the country. The Democratic Republic of the Congo is much larger than a map truly portrays. The Democratic Republic of the Congo’s rain forest is the second largest after the Amazon rain forest. To access this remote land, one must hike through the rain forest or paddle along rivers. To add more difficulties to the search for knowledge, the Democratic Republic of Congo since the 1960s has been in political upheaval.

The endangered bonobo species is an important subject to study because it will allow us to come to an understanding of how our species survived and how we developed into the species we are today. The bonobo is an example of a species in which the environment has played a significant role in shaping its social and emotional patterns. In this tranquil land, the female bonobo, unlike in any primate species, creates alliances with other females. This is unique because in other species females migrate to other communities. This static unity among bonobo females allows for unity among the females. With this close social bonding, females are able to control bonobo society through the regulation of food and the protection of infants. Bonobos provide for an alternative view of what is natural in society. This species shows that evolution does not consistently promote the development of a patriarchal society. The common scientific belief has been that polygyny has been the reason why Homo sapians sapians survived. This theory was based on the fact that males naturally felt it necessary to protect their offspring to help promote the passing of their genetic traits. As a result of this fear, males would form close ties with their female counterparts. This close tie led to the creation of the nuclear family in which a male, female, and child live as a cohesive unit.

This contradicts the argument that society revolves around the belief in a nuclear family as the ideal way of life. Based on limited information, scientists are unable to prove that there is a social model that demonstrates whether humans are closer to the chimpanzee or the bonobo. The bonobo is a species that allows anthropologists to glimpse another way of living in a society. This difference in perspective prevents humans from making universal assumptions about the past. For humans to truly understand where we have come from, we must be able to learn not only about our evolutionary history, but also a vast amount about the social and evolutionary history of our closest relatives, the chimpanzee and the bonobo. Bonobos are the contradiction to the argument that a formation of a nuclear family was present because their environment does not force them to constantly fight for resources. Another reason why there is more cooperation within their large communities is due to males and females being unable to determine who the genetic father of an off-spring is. This allows for a society in which everyone collectively takes care of one another.

Bonobo males, unlike those in the other three great apes, migrate to other bonobo groups after they become old enough to leave their mother’s care. Gorillas, orangutans, and chimpanzees all revolve around a patriarchal society. The reason the bonobo species is remarkable is that females—which are 85% anatomically identical to males—are able to run society based on cooperation with other females. Sexual dimorphism is a driving force for why the majority of males in the animal kingdom function as the dominate gender.

While both chimpanzees and bonobos have policies regarding how a society should function, both are dramatically different. Chimpanzees follow a method of knowing what they want, when they will get it, and how they will get it. Bonobos are not less intelligent, but they simply use different methods to obtain what they want. Chimps resort to violence or power to obtain what they want, while bonobos use sex to solve problems. As previously stated, bonobos and chimps are specialized for behaving in different ways. Chimps function with the method of working together to use violence to obtain power. Bonobos are more in touch with placing themselves in the “shoes” of another bonobo’s needs and desires. With this awareness, bonobos are able to share an understanding without becoming consumed with their own needs and desires.

Making other individuals in a community comfortable is done by forming close bonds with other members. When competition for resources is at hand, tension is released through the rubbing of genital areas. With the use of sex as a method to relieve aggression, bonobos are able to be at peace with not just individuals in their community but also with complete strangers. This rubbing is not exclusive to females; both males and females use it as a form of resolving conflict. Bonobos engage in sex with every partner combination: male-male, male-female, female-female, male-juvenile, and female-juvenile. Despite all this sexual activity, the species’ rate of reproduction is low (single births in 5-year intervals), and to prevent incest, adult females instinctively leave their communities in search for new mates. This happens when females migrate in their adolescent years, leaving their homes around the age of 7, when they develop the first signs of sexual swelling. In bonobo societies, since adult females retain their sexual swelling when pregnant, it becomes impossible for males to determine whether a child is theirs. This ambiguous pregnancy, while making it difficult for females to find a dependable father figure, allows for the community to remain unified because males are not at constant odds with other males over females or killing infants. To show another behavioral difference from other animals on this planet, bonobos understand the importance of procreation, but like humans, they believe sex is an act of pleasure. Sex, in many cases among humans, is seen to be simply an act of procreation because it forces them to accept the fact that humans are just like every other animal on this planet.

The use of tools has always been an indicator of intelligence. However, there are not many cases in which bonobos have been prone to tool usage. Frans de Waal (1998) argued that this does not prove that bonobos are more or less intelligent than their counterparts, the chimpanzees. He argues that bonobos have provided only a few cases because they are not challenged to think critically to obtain food in their environment. Tool use in most cases is a method used to collect objects that pongids cannot obtain without the advantage of tools. While the bonobo has shown rare cases of tool use in the wild, Kanzi, a bonobo at the San Diego Zoo, was able to create Oldowan tools by cracking stones together to make flakes. The reason Kanzi actually created the flakes was based on her desire to acquire food.

Tool use is not a standard that all individual pongids can achieve: Some individuals are more intelligent than others. It is debated if culture is present in other primates. Culture will never be present if one generation is unable to teach another generation a skill. Humans are able to perform this task through many methods such as literature, oral traditions, and events. But for apes, it varies based on the community’s ability to transmit information. While it may seem difficult for people to picture a society such as the bonobos, we can truly learn something about ourselves from watching the social behaviors of this close relative. Roughly around 5 to 6 million years ago, we shared the same common ancestor. Through observations, we are able to glimpse a picture of this past if bonobos have retained traits similar to those of our ancestors.

Language

Communication is a function that allows all living animals the ability to transmit ideas and feelings to one another. Conversing is what separates the living from the nonliving. Each organism on this planet achieves this process in many different ways. The study of linguistics is a comprehensive field that does not study just language in humans; it also has incorporated an extensive study on animals to determine if language is uniquely human. While studies have varied among different animal species, the main focus has centered around our closest ancestors, the primates, and more specifically the four pongids. From the study of our closest living relatives, the science community hopes to discover the true definition of what language is, and it also hopes to shed light on the evolution of human social and cognitive abilities.

As scientists learn more about the hominoids, they will uncover the properties of acquiring language and also the ability for language comprehension. In the early history of studying our closest relatives, most research was performed in labs to test the limits of the human mind. As time passed, a debate arose over which direction science should turn in decoding the answers to the origins of language. In the natural world, we can truly see these species in an unaltered state. However, many of our closest relatives, the pongids, use only a fraction of their intellect. The reason for this is that their environment does not demand that they develop communication beyond only their need to survive and reproduce.

The great apes in their natural habitat dominate their living space. The only true threat to their existence is human intervention. Without their environment challenging them to alter their lives, there is no need for these species to create stronger social relations with one another. Researchers argue that what truly separates the pongids from other primates is that their cranial capacity has allowed them to think on an individual level. As a result, this has not led to the forming of strong community ties. Sharing information with one another does not need to be as specialized as compared to that among members of the human species. In our recent evolutionary past, selective pressures must have forced humans to work together in a cohesive society in order to adapt, survive, and reproduce.

The specialization as stated previously in nonhuman primates is less sophisticated. Most primates use communication as a method of warning other individuals that there are predators. For example, chimpanzees vocalize in as many as 34 distinct calls. Though these rough grunts form a method of greeting, it can also be a form of expression such as excitement toward food or a feeling of compassion when a mother embraces an infant. Recognizing that these four relatives closest to humans are a key to understanding language, scientists are in the process of uncovering evidence about these primates and if they are, in fact, deliberately vocalizing to one another. It is important for scientists to know if these species understand the meaning of calls because it would demonstrate the complexity of their minds. This will help scientists understand if these species have the cognitive ability to understand commands given by humans, which will allow us to test their intellect. While pongids are anatomically unable to articulate all the sounds of our universal grammar, it is more important to focus on their ability to understand what we are trying to convey. It is important to figure out if this is possible because it would show the complexity of their brain, which allows them to adapt to the world around them.

A shift is taking place in the way we study primates. Placing them in a world of human interaction will allow scientists to see their ability to adapt to a different social environment. While determining if other species are able to comprehend our communication system, we must keep in mind the fact that while this communication system works for us, it is evident that it does not mean that we are living an ideal way of life.

To understand species such as the chimpanzee, one must be informed about not just the biological and psychological makeup but also about the behavior of our complex relative. The anatomical makeup of our supposedly closest living ancestor, the chimpanzee, shows that the vocal folds in chimps are too fatty and less muscular than those of humans, and therefore, the chimpanzees cannot create sounds necessary for language. The larynx plays a large role in humankind’s ability to articulate effectively; in chimpanzees, the epiglottis extends well higher in the throat, lessening the range of sounds it can produce. This evidence proves that our closest ancestors are physically unable to pronounce all the sounds capable of human language. Due to the chimps inability to speak with our capacity, scientists are divided on what research approach should be followed to test chimpanzees potential limits. The major division in the science community is between two methods: the use of pictograms, which allows primates to create simple symbolic syntax, or the use of ASL (American Sign Language).

The history of using ASL as a form of communication was first studied in 1965 by Allen and Beatrice Gardener. In their experiment, which lasted from 1965 to 1972, they raised a chimp as if it were a human child. Washoe, the chimp, was able to form simple syntax through the use of sign language in an intelligent and creative matter. Within 3 years, Washoe was able to learn 130 signs. This experiment was the first of many experiments that shed light on the capabilities of chimpanzees and led to the pursuit of studying other primates.

Modern studies pertaining to our closest living relatives have revolved around the alteration of an environment. One variable is selected in which the pongid studied is forced to think critically, forcing it to test its social limits. In 1999, the University of Georgia conducted an experiment that entrenched two apes in a human atmosphere. Panzee, a chimpanzee (Pan troglodytes), and Panbanisha, a bonobo (Pan piniscus), were raised from 6 weeks of age and fixed in human society. The study’s focus was to see the capacity of these species through the use of lexigrams and to see if these pongids could comprehend human speech.

Experiments that proved the complexity of the two pongids were performed by forcing the apes to use their social skills to get what they wanted. The most well-known and successful study was a double study in which a scientist would place a fruit outside of Panzee’s reach. Another scientist would go near Panzee, and she would make the scientist aware of the location of the fruit. The forms of communication that Panzee used were initially displaying her hindquarters as a greeting, and after this greeting, pointing to a picture on a computer screen that displayed the item hidden. After she received the attention of the scientist, she would go outside in her play area and attempt to direct the researcher to the location. This test did not involve just a unique event; this study was practiced multiple times with the use of different locations and items. Usually, Panzee would inform someone of the fruit or image within a 24-hour time span, and in rare cases, within a few days. Behaviorally, the primates do not have the same complexity as humans do in speech, complex learning, or invention, but these behaviors are present to some degree. How will scientists uncover the mysteries of our closest relatives? The truth is that we can truly understand by simply forming a relationship with them, as well as observing them.

Every unexplainable event causes humans to consider the possibility that we are not the only species to actually have a complex brain. The social phenomenon of this world has played a direct role in the shift in our mentality and our understanding of behavior. The consensus since the late 20th century has been the belief that all animals were simple, walking biological machines having no feelings or compassion toward other organisms. Even the father of evolution, Charles Darwin, believed that all organisms follow the practice of survival of the fittest in which all animals are completely fueled by their primordial nonrational instincts, which drive them with any means possible to survive. Each species on this planet is unique and diverse, but this does not mean that we are not all connected through organic evolution. We all experience and react to stimuli to survive. Behavioral science is still flourishing because there is still much to learn about the primates of this world. Understanding and observing the day-to-day experiences of these species will allow us to see how their brain functions and also how our early hominid ancestors once lived.

Future of Primate Behavior Studies

Primate behavior has endless possibilities and many directions in which the field can go; but we must not forget our history and also allow for no “stone to be unturned.” In order for primatology to achieve its goal in the understanding of nonhuman primates, we must exhaust all options in all fields. While research has been seen as a highly competitive and an individualistic practice, it seems all the more logical for anthropologists and other scientists to band together to accomplish our goals. The reason we are motivated to study primate behavior is to learn more about ourselves and the other primates. To allow for the discipline to flourish, we must spark interest not only in our community of researchers but also in the general population. By providing information for people to learn, we allow individuals the opportunity to understand anthropology by creating the means to understand. We are providing readers with the sources, which will hopefully enlighten those who have questions.

Technology has affected all aspects of our lives. This is not contrary to the field of anthropology and the study of primate behavior. The ability to test the genome of individual primates is one of many fields that allow researchers the opportunity to become more attuned with evolutionary research. Knowing which offspring is whose is especially important in bonobos; this allows scientists the ability to create elaborate data, such as the family trees of individual groups. Other studies that have allowed scientists a greater insight into the understanding of our primate relatives are the testing of hormonal levels within species. This has given researchers the ability to gain insight into the reproductive cycles, ovulation cycles, male testosterone levels, and stress levels of the species studied. This is especially important in the study of baboons, which was addressed in Baboon Metaphysics by Dorothy L. Cheney (2008). While new advances in technology are costly, especially for large studies, their availability furthers the understanding of primates. As time progresses and technology becomes more efficient, these products will become obtainable to all.

Technology allows primatologists to obtain information on a more consistent and less invasive basis. In particular, by using radio collars to track species, scientists will not have to be constantly on the move for fear of losing the group being studied. The great benefit of these forms of monitoring groups is that scientists can watch over multiple colonies, which allows for cross-cultural studies. While advances in technology allow humans to study our closest ancestors with more efficiency, we must not forget that even though technology has allowed humans to achieve many goals, we have also caused great harm to our world. We must remember that humans have been in interaction with other nonhuman primates for millions of years, and for us to keep this possible in the future, we must be responsible and environmentally friendly.

While the scientific community knows there is evidence to prove this fact, the difficulty of trying to get into the minds of our closest living relatives remains. Do the great apes and the lesser apes have the rational faculty to understand the reasoning behind their actions, or is it simply that they are performing a task through mimicking? Are primates able to create and maintain culture, and are primates restricted to only nonsymbolic language? Can these animals understand abstract thought by referring to symbols that are not physically present? In many cases, these questions cannot be addressed in the natural environments of these species because their environments do not demand that they use their complex brains in this fashion. This is why it is important to not only study primates in their natural environments but also to incorporate these animals into human social contexts.

Conclusion

The future of primatology has endless possibilities. What makes primatology such a unique focus is its ability to cover many areas of specialization. A comprehensive study has foundations in genetics, zoology, anatomy, veterinary medicine, behavioral ecology, anthropology, sociology, psychology, and linguistics. Since the 1950s, people have been curious to not only learn about our closest living relatives but also through learning about these species to learn something about ourselves and where we have come from. The major reason why primatology has been able to make the progress it has made is because in the science community, people treat the field and subject with utmost respect and have decided they will devote their lives to this field. Without scientists who truly love what they are doing, primatology would never achieve its goal in understanding the nonhuman primates of the world. As in any subject, the only way for us to continuously expand our knowledge is to establish the general descriptions of the subject in order to create a meaningful framework. The focus of broad general and quantitative studies during the 1970s and 1980s allowed for future studies to achieve the success we have today. In our focus to find the specifics of our study, we must not forget our history and how to perform broad studies. Every day, we are uncovering new species, and while it is necessary to obtain more and more information about primates, we know we must also create a comprehensive view of the new species in the taxonomic kingdom. As species are being discovered, we must remember that as more and more human contact takes place among the primates, the more likely that our chances to study these species will begin to dwindle. As much as we as humans have created and discovered remarkable things, we intentionally and unintentionally have the ability to alter not only our own lives but also the lives of other organisms around us. To discover the information we need, primatologists must work together in the effort to enlighten not just the science community but also the human world.