Part One: Primate Observation Field Notes
The observations of the primate took place at San Francisco Zoo. The following information provides the comments on the field notes made about the two primates – the Colobus Monkey and the Western Lowland Gorilla. The Colobus Monkey – a medium sized monkey of moderate build at San Francisco Zoo is found in the Doelger Primate Discovery Center (DPDC). Together with other species such as the pied tamarins, black howler monkey, siamangs and the squirrel monkeys, the colobus monkey is managed at DPDC under the Association of Zoos and Aquariums’ Species Survival Plans. These plans are designed to protect those species which are in danger or faces an imminent threat to their survival in their natural settings (San Francisco Zoo). Their exhibit serves among other purposes educating and sensitizing the public on the importance of all animals in the maintenance of genetic diversity. Physically, the Colobus Monkey adorns a primarily glossy black fur covering that sharply contrasts with its bushy white tail. The long hairs covering their face – the mantle, whiskers, and beard are white in color. Unlike the adult, the colobus newborns are whiter with short furs. It is believed that their white mantle fur and long bushy tails act as parachutes during long leaps in the air. Physically, the colobus has Light-bone structure and elongated limbs. A combination of these factors makes it easier to jump from branch to branch. A close look at their limbs reveals that they have four digits minus a thumb on their forelimbs. In reference to the missing thumb (sometimes the opposable toe), the monkey is referred to as ‘colobus’ meaning the ‘mutilated’ one (San Francisco Zoo).
The colobus monkey is a herbivorous species feeding exclusively on tender leaves, budding flowers, fruits, and soft twigs. At the zoo, the primate receives occasional diet supplements in the form of vegetables, monkey chow, and a variety of fresh fruit. Socially, the colobus is the most arboreal of the monkeys. They tend to spend most of their lives in trees and rarely descend to the ground. During arboreal movement, they use branches as trampolines, bouncing on them to get the required liftoff for leaps. Despite their inherent arboreality, the colobus is very social often living in troops of more than five members made up of a dominant male, several females, and young ones. The troop movement and socialization also appear to be confined to the group members in a defined geographical space. This territory is well demarcated, and outsiders are systematically excluded from it. The monkey communicates with vocalizations at different pitches. However, the most distinct are the male roar, the squeaks of the young, and the guttural "orr-orr" sound from an isolated or stranded troop member (San Francisco Zoo). The females also appear to show extra care and concern for the young. When feeding the colobus move in a systematic slow and deliberate movement, quietly reaching for leaves, twigs, and flower buds. In their sexually mixed groups, the colobus breeding behavior is polygamous often comprising of one dominant male and about four reproductive females. There is usually mutual grooming, and squabbles are rare. Their gestation period is six months.
The Western Lowland Gorilla (Gorilla gorilla gorilla), unlike the Colobus Monkey, is a critically endangered species, and so they are kept in protective reserves such as the Jones Family Gorilla Preserve (JFGP) at San Francisco Zoo (San Francisco Zoo). In their natural habitats, the gorilla is threatened by human activities such as deforestation, human encroachment, and deliberate hunting and killing. Covering about one acre of land, the JFGP provides an expansive habitat of trees, grasses, and rocky outcroppings to the Western Lowland Gorilla. At the exhibit, a wall of viewing windows provides openings to see the gorillas up close as they go about their activities – resting, eating, and interacting with one another.
Compared to other gorilla subspecies; the Western Lowland Gorilla is much smaller and lighter, have short hair, a wider skull, and a conspicuously more pronounced brow ridge. The ears of the primate also appear small in relation to the size of the head. Moreover, there is also the most noticeable differences in physical stature between the sexes. The female gorilla is about half the size of the male – commonly referred to as the silverback (because of the silver hair at the back). The gorillas have a brownish-grey coat with a red or auburn crest. Other than the back-silvery hairs, the male also has a patch of whitish hair on their thighs, grading into their overall black coat. The faces of the gorilla are bare, have a short muzzle, wide nostrils, with small eyes. Their ears also lie close to the head. When they move, the gorilla walked on four feet in a special kind of locomotion known as “knuckle-walking.” Despite their enormous size, the Western Lowland Gorilla are shy and peaceful. At the zoo, the species live in a small group of four, are most active during the day, and spend a greater part of the day looking for food. They are mostly herbivorous, feeding primarily on leaves, fruits, and shoots. At the JFGP, like other primates, they receive dietary supplements in the form of vegetables, fruits, and leaves. Occasionally, however, they feed on termites and ants. The Western Lowland Gorilla is polygamous in nature, often mating with all the females in his troop.
Part Two: Section One
The Western Lowland Gorilla (Gorilla, gorilla, gorilla) are found at the JFGP Reserve. The area covers about one acre of land with a Primate Discovery Center consisting of a conspicuous foot enclosure of about 200,000 cubic meters (San Francisco Zoo). It has exterior walkways and platforms for viewing the animals. There is also a hands-on discovery location and a nocturnal gallery within the JFGP structure. The main area for the primate exhibit is an open space of trees and grasses. As at 2014, JFGP housed four female Western Lowland Gorillas – Nneka, Bawang, Zura, and Monifa, one male silverback (Oscar Jonesy), and the young one – Hasani – the offspring of Monifa and Oscar Jonesy. However, Hasani alongside another young one named Kabibe are dead (Noyes). Hasani was electrocuted while an automatic electronic door (Noyes) trapped Kabibe. In the exhibit area, a path links visitors from the JFGP to Leanne B. Roberts African Savanna Reserve, where there is more of the African animals (San Francisco Zoo). Besides, there is innovative graphic images and information at the exhibit section telling the story of the Western Lowland Gorillas.
The Colobus Monkeys at the Zoo are two kinds: the Angolan Black-and-White Colobus (Colobus angolensis) and the Eastern Black-and-White Colobus (Colobus guereza) (San Francisco Zoo). The Colobus guereza is found at the Thelma and Henry Doelger Primate Discovery Center (PDC) (San Francisco Zoo). At the PDC, there are several monkeys and visitors can enjoy the dual-level view of this primarily arboreal primate. It has vertical spaces and high-rise structures for aerial viewing of the colobus. The area has an expansive natural outdoor space for the animals. The general view of the enclosure is that of open air with stairways in the foreground (San Francisco Zoo).
The most typical behavior of the Colobus is its arboreality and the tendency to jump long distances between branches. This behavior is partly associated with food acquisition and the animal tend to remain on the canopy of trees and will occasionally come down to forage. Because the colobus prefers the young and tender twigs, they spend much of their time on treetops in search of such food resources. The animal is mostly folivorous, feeding on tender leaves, flowers, fruits, and buds at the top parts of the tree. However, in less densely tree populated areas; the colobus can come to the ground though for short periods. Therefore, the use of the trees of foraging as well as traveling appears to be the species specific and most obvious behavior.
The core of the social groupings in Western Lowland Gorilla (Gorilla gorilla gorilla) is the male-female bond. This behavioral attribute also appears to be the most striking trait. It is a behavioral trait designed for mating and reproduction (San Francisco Zoo). The close primate proximity and grooming reinforces the behavior. The females develop a strong relationship with the males in the troop for protection and mating opportunities. There are also moments of intense aggressiveness between Female-Female relationship as observed at the zoo when two females aggressively charged on to each other. The female-female relationship is also different along lines of relatedness in which maternal relatives relate more closely and affably than nonrelative members are. Therefore, this close relationship revolves around social access to reproduction and mates. The social behavior of the primate is pegged on group socialization, playfulness, and sexual proximity (Sherwood, Subiaul, and Zawidzki).
Section Two: Primate Comparison
The Colobus Monkey and the Western Lowland Gorilla are two primates that have evolved different physical as well as intellectual characteristics throughout evolutionary time to respond and cope with their various needs and the changes in the environment they evolved. For instance, the Colobus have a long bushy and easily visible tail while the Western Lowland Gorilla do not have. In addition, the Colobus is physically built for arboreal life (life in the trees), the Gorilla, on the other hand, is made for mostly terrestrial life (on the ground). As much as the monkey and the gorilla are different, they are also similar in several other ways. Observable features such as body form, posture, taxonomical structures, social, dietary, and feeding habits reveal that the Colobus and the Western Lowland Gorilla could be differentiated (San Francisco Zoo). The observed traits of the Colobus show that the monkey is adapted to climb and move among the trees. It is, therefore, arboreal. In the trees, the colobus walked on all four limbs most of the time and was only spotted on the two hind legs when eating on a relaxed posture. Their food habit is primarily herbivorous. Compared to the Colobus the Western Lowland Gorilla is the largest between the two. They were observed mainly on the ground, but they can also climb trees capable of supporting their weight. They have long and powerful forelimbs than their hind legs. On the ground, the gorilla, walk on the soles of their feet and the knuckles of their forelimbs. They can also walk on their legs but only for short distances. The gorilla live in groups with a dominant male – the silverback. However, the Western Lowland Gorilla hold a higher evolutionary position than the Colobus. The lack of the tail in the gorilla also serves as a very distinctive observable feature between them and the Colobus (San Francisco Zoo).
Nevertheless, both the monkey and the gorilla live in groups – are social animals. Their social groupings rest in the balance of individual need for protection, provision, and access to resources with the necessity of the collective group. There is also the sexual similarity between the two primates. They both exhibit sexuality for mating and social relationship. They are both polygamous species – one dominant male and multi-females. Both the Colobus and the Western Lowland Gorilla are intelligent primates, capable of communicating and manipulating objects. With no vocal cords, these two primates could use sign language, vocalizations, bodily expressions, and gestures to inform others of their physical and psychological states and present concerns. It was also common to observe the two primates communicate affection through affiliative behaviors that included sitting close to one another, touching, and mutually grooming. Both the Colobus and the Gorilla showed mutual grooming to not only reinforce the male-female bond but to seek and build sexual relationships (San Francisco Zoo). One fundamental reason why there are differences between these two primates is that the colobus and the gorilla evolved following different paths (Sherwood, Subiaul, and Zawidzki). They, however, share some basic characteristics because they evolved from an extinct common ancestor. Their exploitation of different ecological niches and environments led to the difference we see between them today. Regardless of the differences, the colobus and the gorilla retains significant features they derived from their common ancestry several years ago.
Section Three: The Effect of Captivity
Increasing body of research indicate that captivity increases the potential for ‘domestication’ to occur as a by-product of the primates being kept and bred in confinement (O'regan and Kitchner). One striking observation was the loss of response to distractors and the alteration of primate defensive as well as sexual behaviors naturally expected in the wild varieties (Reynolds). Smulders assert that captive conditions evoke abnormal behavioral patterns such as repetitive rocking and self-mutilation in the held primates. Given the emotional and cognitive abilities of primates, the zoological collection can have significant effects on the animals. Social deprivation, localized movements, rigid diets, and frequent disturbances from zoo visitors can all have collective implications for the primates held in zoos. Unlike their wild counterparts, primates in captivity show limited and often altered reproductive behavior and cycles (Reynolds). They also show decreased exploratory behavior due to limited space and a heightened tendency to hide arising from such factors as habitat size limitations, forced closeness to humans, and frequent feeding conditions, check-up, and husbandry (Hosey).
Because of habitat differences, I would expect these animals to act differently in the wild. The first step in identifying the primate responses in the zoo environment with their responses in the wild is to compare the effects of the variables of the zoo setting with those in the wild (Reynolds). Notable variables include the constant presence of numerous people in zoos (Hosey). These people are usually unfamiliar to the primates unlike in natural environments where such encounters are minimal. There is also the effect of the restricted space. In fact, the physical space available for primates in zoological collections is usually much less, than the animals would range over in the world environments. Another and perhaps the most important variable that affects the primates in captivity is the aspect of management. This attribute would conspicuously be absent if the animals were in the wild (Hosey). For those in confinement, group numbers, membership, feeding routines, health and reproduction cycles are managed to some extent by the zoo. In this perspective, it is likely that the behavior of primates in zoos is affected not by a single factor but by an interplay of a combination of several zoo-related variables acting together (Hosey).
Section Four: Insights into Human Behavior
The studies of primates, therefore, provide essential clues in the reconstruction of evolution, adaptations, and behavior patterns of our earliest ancestors. The differences that exist among the species themselves and between humans show that the animals have all changed in various ways from their earlier times. The different changes in structure and physical attributes also indicate that certain forms of such qualities that the animals now exhibit were not present among the original ancestors (Smulders). Ultimately, therefore, studying the primates tell us that humans share some traits with the primates for two main reasons. First, the humans and primates are closely related, and they have inherited the traits in question from a common ancestry. Secondly, the study shows that the shared characteristics between humans and the primates are an adaptation to similar environment and evolutionary pressures (Smulders; O'regan and Kitchner). Therefore, understanding these differences and similarities is enlightening when trying to understand the very nature of humanity.
Works Cited
Hosey, Geoffrey R. "How does the zoo environment affect the behaviour of captive primates?" Applied Animal Behaviour Science 90.2 (2005): 107-129. Print.
Noyes, Dan. "San Francisco Zoo knew dangers years before baby gorilla died." ABC - Eye Witness News [Los Angeles] 15 Nov. 2014: n. pag. Web. 1 May 2016. <http://abc7.com/news/san-francisco-zoo-knew-dangers-years-before-baby-gorilla-died/396901/>.
O'regan, Hannah J., and Andrew C. Kitchner. "The effects of captivity on the morphology of captive, domesticated, and feral mammals." Mammal Review 35.3-4 (2005): 215-230. Print.
Reynolds, V. "Some Behavioral Comparisons between the Chimpanzee and the Mountain Gorilla in the Wild." American Anthropologist 67.3 (1965): 691-706. Print.
San Francisco Zoo. "San Francisco Zoo." San Francisco Zoo. N.p., n.d. Web. 1 May 2016. <http://www.sfzoo.org/index.htm>.
Sherwood, Chet C., Francys Subiaul, and Tadeusz W. Zawidzki. "A natural history of the human mind: tracing evolutionary changes in brain and cognition." J Anatomy 212.4 (2008): 426-454. Print.
Smulders, Tom. "By Studying Animal Behaviour We Gain an Insight into Our Own." The Conversation. N.p., 8 Nov. 2013. Web. 1 May 2016. <http://theconversation.com/by-studying-animal-behaviour-we-gain-an-insight-into-our-own-20001>.
