Primates are some of the most interesting animals to watch and learn about whether it be in person at a zoo or seeing a film or documentary on wild ones in a natural environment. Part of this reason is due to the incredible amount of similarities found in between primates and humans. After observing two different primate species at a local zoo, I found out that by observing their behavior, we gain a small insight into human behaviors and their roots. Today I will discuss the different types of behavior I observed as well as the effects of being in captivity and how this helps us understand hunan behavior. On sunny April 19th this year, I visited the San Francisco Zoo and the first species I observed were the gorillas, also known as Gorilla Beringei. Upon approaching the gorilla habitat, at about 1:30 p.m., I noticed the enclosure was roughly about fifty yards in diameter. Throughout the enclosure, there were different levels of ground elevation varying from small hills, to large rock structures placed about twenty feet away from the gorilla cages inside the habitat. There were also many plant or bush like shrubs around as well as trees varying from shape and size throughout the enclosure. The overall shape of the enclosure was similar to an octagon which supported different observational vantage points from a few different sides. The gorillas are the largest primates still existing today. The gorillas in the enclosure varied in size and appearances. All the females were much smaller then the male silverback, however within the female group, their sizes also varied. Some females within the group were less massive and more lengthy then for example the female in charge of the newborn gorilla. The “mother” of the baby gorilla, Kabibe, was much larger then the other females and she seemed to have more authority within the social group.
The male silverback, Oscar Jones, was impressively larger then any other gorillas in the enclosure and had a much larger head and arms in comparison. He had long thick black hair with a patch of silver on his back symbolizing maturity. In total, I observed about six to eight gorillas out of the cages and interacting within the enclosure. The second species I observed around 3:40 pm were the siamangs, or symphalangus syndactylus. Their enclosure was much different then the previously observed gorillas enclosure. This one was about fifty feet high, 30 feet long, and 20 feet wide and in the shape of the letter “L”. It’s made of reinforced glass from the bottom to about 10 feet high, then becomes a chain linked metal cage the rest of the way up. The structure contained many different objects from which the siamangs were able to use to climb up or down. Some of these objects included, climbing logs, swings, many thick pieces of rope, cylindrical shaped rubber tubes, planks of wood, and many other suspended objects. Towards the bottom of the enclosure, there were also a lot of plant life and bushes or flower like things where the siamangs could sit or interact with one another when not climbing around. Within the enclosure, there were two siamangs. Although not labeled, since siamangs are monogamous primates, I assume one was male and one was female. Physically, the siamangs are just a bit larger then the other gibbons however still small in comparison to the apes. They have no tails, are slender and long armed as they are arboreal lesser apes. They are covered with long dense black hair and have long hooked nails.
Siamangs are also known to have large throat sacs which they can use to let out a very loud call to warn against predators. However, neither of these siamangs had the adaptive throat sacs. Also, there was not much difference in size between the male and female gender. After observing the two primate species and reviewing my field notes, I noticed the two species although both part of the ape family, are not that similar in fact. For example, the gorillas social organization consists of a one male, multi female group with the male being the alpha leader. He ensures that it is his genetics being passed on to the offspring and that is the only way he will protect and partake in the baby’s life. Due to being a one male, multi female group, it is not uncommon for gorilla males to kill any infant they assume is not theirs. There also seemed to be a sense of hierarchy amongst the females themselves, with Kabibe’s mother, at the top of the female group. However, the male silverback Oscar Jones, was still maintaing authority amongst the entire group by charging the females. On the other hand, the siamangs are a pair bonded group whom select mates for life and have a family. In the enclosure I observed, there were only two siamangs present who behaved very differently from one another.
One siamang continued to be very active, swinging throughout the cage and constantly climbing up and down the metal fence. However, the other siamang, which I believed to be female, sat on a small rock towards the bottom corner of the enclosure and did not interact with any bystanders or the other siamang at all. Also, my friend and I noticed this sitting siamang also seemed to appear as if it were depressed. Many times the active siamang would swing down and try and interact with his partner and the other siamang would just ignore him and continue staring down or out the glass. One of the gorillas I was observing displayed a way of acquiring food which I thought was quite intelligent. She grabbed a thin leaf filled branch from a tree and placed her hand at the top of the branch. Starting from the top she pulled her hand down towards the other end pulling any leaves out together instead of one by one. She then disposed of the branch by throwing it a few feet away from her. This showed a level of intelligence I have not seen in other primates. The gorillas mainly stick to eating leaves and vegetation found in their enclosure from many trees and plants around. This similar to their natural habitat, does not offer them lots of nutritional value, however is available in large quantities and available year round. I am also assuming they are fed fruits by zoo employees as well for nutritional quality and value. The three females outside in the enclosure seemed to be isolated about 20 feet away from each other and spread around the enclosure. They did not seem to be sharing any source of food or interact much with one another unless they were nearing the cage door within the enclosure.
The siamangs did not seem to display any signs of higher intelligence. One continued to constantly move around the cage by climbing up then swinging back down. The other siamang just sat in isolation and was not physically active much at all. They did not share anything amongst themselves and did not interact much either. The two primate species I observed did not have much in common, except for their diet. Both the gorillas and the siamangs are both primarily vegetarians and consume different types of leaves, fruits, and other plants found in their habitats. I was not able to observe how the siamangs acquired their food or how they react to “meal time”, however based on my observations I assume the siamangs would not share much either due to their lack of interaction with one another. This throws me off because according to what I have learned in class, the siamangs are in fact mates with one another for life and yet they did not interact with one another at all during my observations at the zoo. I believe these similarities in diet exist because that the siamangs and gorillas are part of the ape family. However, the differences in behavior, mating, social organization, and intelligence also exist due to the fact that they are separated between the “lesser apes” (siamangs), and the “great apes” (gorillas). Another reason why these differences might exist is due to where the species originated from.
Gorillas originally were from Africa while Gibbons were found from Southeast Asia. Overall after reviewing my notes, I noticed that the Siamangs are much less intelligent then the gorillas, yet more active. I believe this is because the siamangs are much smaller, requiring less energy to move about their enclosure in such a fast and excited manner. The gorillas on the other hand are much more complex in behavior as they actually interact with one another by expressing sounds and or physical actions. They also seem to be aware the fact that many people are around them watching, and they also react to this by hiding back in the cages or moving away behind a tree or rock structure. I have always believed that being held captive in a zoo, is no where close to being free in your natural habitat. How can one take an animal who should have the ability to roam endless land and have the need to survive in the “natural” world and put them in a restricted enclosure, a fraction the size of their natural habitats and claim that these animals are happy there? I personally believe being in captivity and on display in a zoo has many negative effects on these animals. While observing the gorillas, they seemed to be heavily affected by their environment and surroundings. In a gorillas natural habitat, you would most likely find them playing with one another, acquiring food, and being active. However, most times in zoo’s you simply find the gorillas not really doing anything besides just sitting there.
These are most likely due to psychological effects brought on by being captive and put on display to thousands of people all the time. While observing, I noticed the gorillas did not really do much besides move around to their own spot of the enclosure, about twenty feet away from one another, and just sit there and stare at the people watching them. Also, these gorillas suffer mental trauma from being teased or provoked to a level where they feel threatened by all these yelling kids and or adults. I do not believe the behaviors exhibited by gorillas in captivity are “natural” due to the fact that gorillas are very intelligent. According to GorillasWorld.com, “As humans are watching them they will be watching as well. This is why they often pick up behaviors from people.” As a result, behaviors seen by gorillas in a zoo would not be the same behaviors shown by wild gorillas in natural environment. With thousands of people standing around the enclosure yelling and making gestures towards the gorilla, it is safe to say the gorillas observe the humans behavior and repeat behaviors they have learned. The siamangs I observed also display a bit of natural and unnatural behaviors as well. For example, siamangs are arboreal primates who live in tree top canopies and are rarely seen walking on the ground. They use their long limbs and fingers as hooks to swing from branch or vine to another and that is how they maneuver throughout the forests.
One of the siamangs I was watching was very active and continued to swing back and forth throughout his enclosure almost the entire time I was watching. He would use logs and ropes to climb up to the top corner of the cage, then he would observe from up there for a few seconds. After, he would make his way back down towards the bottom of the enclosure and would leap around. This is natural behavior to be seen by a siamang even in the wild. However, the other siamang within the enclosure exhibited some worrying signs of unnatural behavior. This siamang was sitting on a rock of some sort around the enclosure floor and would stare down towards the ground or look out the glass. However, she would not move at all throughout my entire observation time and really seemed depressed. At one point, the other active siamang swung down and got very close to her and still she did not move or interact at all. Im assuming this is a psychological effect brought on by being trapped in such a small containment instead of being able to roam about the forest and be free. I believe that this specific siamang has been held in captivity for a while longer due to the behavior shown. Observing these primates in their natural wild environment would have significantly different behavior observations. Living in the wild, these primates experience struggles to survive such as finding sources of food, competition for mating, and also predators and dangers.
These are not really things captive animals in zoos experience due to human intervention. For example in the wild, gorillas are moving to a new “camping ground” very often due to predators such as large cats and build a sleeping nest to stay protected. This is natural adaptive behavior found in gorillas; however, you will not see this in captive gorillas because the only predators they experience are humans taunting or screaming at them and they do not have enough space available to travel distances. As a result of these observations, primates and other animals in captivity may not exhibit natural behaviors observed in their natural environment. After spending the day observing the behaviors of both the gorillas and the siamangs, I see some behavior patterns that I also see in humans. For example, the siamangs find mates for life and raise a family and that is their social group. This is basically most families around the world. Our social group normally consists of us with a single mate whom we raise children with. I believe the fact that we as humans ideally choose to settle down with a single partner and raise children has to do with our culture and not necessarily as an instinctual choice such as the siamangs.
As humans most of us find it wrong to have more then one mate or parter and we call it “cheating.” However, based on my observations of the primates, it is a natural and instinctual decision to try and mate as much as possible to ensure your genetics being passed on and carried through the future since that is life’s main objective. Another example is the effects of captivity the depressed siamang suffered from. This is very common in humans as well to become anti social or depressed when placed in a small room such as a jail cell. Studying primates can help us understand more of where humans came from due to our recent shared common ancestor. We are able to see some behavior patterns from the primates found in humans as well, however there are many behavioral patterns in the primates which is uncommon for humans. For example, the gorillas tended to be in isolation and spread out throughout the enclosure for most of the time. Humans on the other hand, if having to live together for a long period of time such as the gorillas, are more likely to build a tight knit group and have lots of interactions with one another.
Based on my observations, there are some behavioral patterns found in both primates and humans. However the cause of these patterns differ based on instinct and adaptations in primates compared to culture and morality in humans. I believe that by studying and observing behavioral patterns in primates, we can better understand where some of our own actions and behaviors derived from, and whether its something that is instinctual and preprogrammed, or if it is something we have created and added to part of our culture as humans.
Cawthon Lang KA. 2005 October 4. Primate Factsheets: Gorilla (Gorilla) Behavior . <http://pin.primate.wisc.edu/factsheets/entry/gorilla/behav web 2014 http://www.enchantedlearning.com/subjects/apes/siamang/ web. 1999 O’neil, Dennis. http://anthro.palomar.edu/primate/prim_7.htm web. 2012 http://www.gorillas-world.com/gorillas-in-captivity/. web 2014