Greensboro Science Center Reflection

I deeply enjoyed our trip to the Greensboro Science Center today. It was interesting to notice and feel the difference between the North Carolina Zoo in Asheboro and the Greensboro Science Center. I enjoyed the Science Center more- because of the more intimate feel. Despite the Science Center functioning on a smaller level than the North Carolina Zoo- we saw a shockingly diverse set of primates. Javan gibbons, Ring-tailed lemurs, Red ruffed lemurs, Mongoose lemurs, and Black howler monkeys. The lemurs might have been my favorite to observe. Because there were three different species in one enclosure- it provided me with a greater opportunity to compare and see whether rank comes into play with species. We were able to see how well lemurs can blend in with their surroundings- it took us a while to spot the Mongoose lemurs. They slept during most of our time while the Ring-tailed lemurs spent the most time actively climbing, playing, and exploring. The Red ruffed lemur for the first half of our time at the lemur exhibit. About 10 minutes in, he or she jumped down from the perch onto a log that was a Ring-tailed lemur was situated on. When the Red Ruffed lemur climbing down onto the long- I realized just how big it was. The Ring-tailed lemur realized the Red Ruffed lemur had climbed onto the end of the log- and quickly scurried away into the barrel hanging from the ceiling. The Red ruffed lemur comfortably situated itself in the Ring-tailed lemurs place. I wondered to myself whether this was a power display- the Red ruffed lemur seemed more dominant than the Ring-tailed. I watched for any subsequent displays but found none- the Red ruffed lemur was didn’t move from its spot once acquired. This was the only dominant behavior I really saw while at the zoo- which surprised me. The Javan Gibbons were very docile and we saw a variety of grooming behavior between the two adults. We also saw grooming among the Ring-tailed lemurs. The Howler monkeys were curious about everything when we observed. It was interesting to see the different demeanors and interactions between pairs.

I also very much enjoyed watching the Javan Gibbons playing with their young infant. The family of three sat on a ledge in their enclosure. I assume the mother was on the top ledge and the father was on the ledge just below her (I was not able to distinguish mother and father). But the infant sat on the top ledge- eager to play with the two ropes above their heads. The infant jumped up and swung back and forth- from mother to father. The father (I assume) reached out halfheartedly towards the infant when he seemed to want to return to the ledge. The mother (I assume) had a habit of sticking her hand out and rapping the father when the father made a halfhearted attempt. The infant always swung back to the top ledge and returned to the group up by the mother (I assume). I really wish I had been able to distinguish mother from father during this moment! If the mother was on the top ledge, the situation would say a lot about mother-juvenile relationships and father-juvenile relationships. If anything, the situation was great to watch.

leon-and-isabella-together

Overall, I really enjoyed my time at the Science Center. I enjoyed the casual observations- I didn’t need to quickly scribble down every movement like during the gorilla observations. These observations were much looser and I was able to discern interesting moments based on my interest.

Picture: http://greensborosciencecenter.wordpress.com/tag/javan-gibbons/

Polyspecific Associations

Polyspecific associations are associations between species. As primates often live in areas lush, fertile, and viable forests- density of species is a natural result. However this closeness is emphasized when food resources are similar. This will result in species exploiting certain food areas. Regarding food, members of the same species, will bond together to get group access to a certain food source. In Primate Behavior Ecology, Strier gives us a loose diagram of all the factors that go into interspecies associations and it’s clear to see how many diverse and complex factors will play a role. Some of the factors include dietary diversity within species, population densities, distribution of food, predation pressure, and availability of potential partners, geography, presence or absence of competitors. Strier makes it very clear that polyspecific associations are the result of a myriad of circumstances and realities in the primate world.

An example exists in Manu Nation Park, Peru where squirrel monkeys associate with brown capuchin monkeys. Brown capuchins are larger than squirrel monkeys and can physically win out in a confrontation. Strier states that squirrel monkeys maintain the associations because capuchins have strong jaws that are able to open difficult nuts and fruits. Squirrel monkeys do not have this ability so their associate with capuchins effect their diets. The nuts and fruits that have been discarded by capuchins will likely be eaten by squirrel monkeys. This is an example of a polyspecific association that benefits one group and not the other.

squirrel_monkey6 Cebus_apella_macrocephalus_(Brown_Capuchin_Monkey)

(Squirrel Monkey top, Brown Capuchin on bottom)

Strier gives another example of a beneficial polyspecific association at the same location between saddle-back tamarins and mustached tamarins. These two species have formed a permanent association. These species forge together, defend the same range, habitat preferences, and eat a similar diet. Their diet is really what brings these two species together. Saddle-back tamarins remain on the group and mustached tamarins forage in the trees. Insects that are dropped by the mustached tamarins are often caught by the scavenging saddle back tamarins below. It has also been recorded that species will follow one another to food sources that are less known or more abundant. However, diets change with the season- so polyspecific associations often change with the seasons. I found primates motivated to form polyspecific associations due to food to be slightly more interesting then predator-prey associations because the way in which a primate accesses and maintains a food source fascinates me. The way primates will adapt their behavior, form alliances, and shrewdly create a system beneficial to themselves (like squirrel monkeys) is a sign of developed cognition and awareness.

References:

Strier, Karen B. Primate Behavioral Ecology. Boston: Allyn and Bacon, 2000. Print.

Pictures: http://commons.wikimedia.org/wiki/File:Cebus_apella_macrocephalus_(Brown_Capuchin_Monkey).jpg

http://a-z-animals.com/animals/squirrel-monkey/

How do we assess cognition?

I did like Ape Genius- I thought it brought up great observations about rational and logical characteristics of primates. But like many other mediums that focus around primatology- the film was still focused around humans. It studied the cognition and learning abilities of primates but in relation to ourselves. “What can we learn about us?” “What makes us human?” It’s the evolutionary story of how we arrived.” I do understand that discovering more about the human condition and our historical story is a noble goal, but I prefer learning about primates as a species rather than filtering their life and skills through the human experience.

Cognition often involves intention and understanding. According to Strier, Researchers measure cognitive abilities in three major ways. First, researchers can examine the mechanism by which primates learn their cognitive abilities. Often times, tasks are created, manipulation of circumstances are carried out to assess in what ways primates learn and understand. The second way involve ecological pressures. In other words pushing primates to prove their intelligence by affecting say food resources or involving the necessity of tools for survival. The third way involves examining social hierarchies. Participation in hierarchies requires understanding, negotiation, and bargaining. Strier states that in each case “apes demonstrate abilities that prosimians and monkeys evidently lack” (258). I think the ways to measure cognition speak to the complexity of the abstract concept of “cognition” and understanding. I personally think cognition to primatologists, researchers, and scientists in general means a heightened sense of awareness. That heightened sense of awareness is usually determined by humanity’s achievements. We create the measuring stick through our own experiences. As a result, we judge species by their ability to reach a similar level of understanding and learning as our own.  The distinction between learning and imitation is arbitrary in my opinion. Strier states “Young primates have ample opportunities to observe their mothers, and in most species, other group mothers. Yet there is little evidence of active teaching among any primates except humans and possibly chimpanzees” (258). I think from this statement I am supposed to assume that humans teach their young- and they learn rather than imitate. Whereas in general, primate infants imitate their mothers- and their mother’s don’t actively them- the juveniles simply imitate. I don’t see the evidence to back up a statement like this. No scientist can assuredly say that primates don’t teach their young because it’s clear that they do- otherwise primate species would cease to exist if the juveniles were not taught by their parents how to survive. There always seems to be a fine yet defined line that scientists draw between humans and primates. We are so similar- but humans are more developed and complex and intelligent. That difference creates a space where it is acceptable to impact several species to fit our desire for more knowledge. It currently is acceptable to use primates in experiments because they do not have the same levels of awareness or intellect as we do. It’s interesting because as scientists are discovering more and more about the cognitive abilities of primates- it will become more and more difficult to justify keeping primates in captivity to serve our purposes. Human-like cognitive abilities seem to be a get out of jail free card. I am interested to see whether these new cognitive discoveries will blur that fine line between humans and primates. Will impressive levels of cognition and awareness save a species from human interference? Time will tell.

References 

Strier, Karen B. Primate Behavioral Ecology. Boston: Allyn and Bacon, 2000. Print.

Second Article Review

This week I will be reviewing an article from the Journal of Pragmatics published in 1988. The article written by Francine Patterson, Joanne Tanner, and Nancy Mayer is titled Pragmatic analysis of Gorilla Utterances: Early Communicative development in the Gorilla Koko. Koko is a female gorilla born on July 4th 1971. When she was one, Koko began to participate in a language project aimed at discovering the possibility of inter-species communication. The first 11 months of the project occurred publicly at the San Francisco Children’s Zoo Nursery. Koko spent 5 hours a day with trainers for the first 11 months. Then her exposure to the public was brought down and trainers began signing with her 8-12 hours a day. According to the article “Koko was exposed to simultaneous communication (SIMCOM), the use of American Sign Language accompanied by spoken English, in an environment designed to approximate that of a human child” (4). Vocabulary was taught by molding and imitation. Molding takes place when trainers mold the student’s hand into the proper motion. Imitation or “modeling” requires the student to imitate the chosen sign of the teacher. Koko progressed wonderfully- with major cognitive advances coming monthly. In the tenth month of the project, Koko began to announce her intentions through sign language. Her vocabulary began more varied and Koko expressed more of her desires and wishes. She began to use signs for functions that she once used vocalizations for. When left alone in a room, Koko would cry out or shriek, but towards the end of the project, she was signing in response to situations like that. Signing “come” rather than shrieking.  

The researchers conclude that the data collected from Koko indicates that “Koko made use of a range of pragmatic functions- labeling, practicing, repeating, requesting action, protesting, answering, questioning, greeting, and calling” (20). Patterson, Tanner, and Mayer believe that the behaviors observed in Koko are similar to those “expressed by human children in the early stages of language acquisition” (20).There is a great debate surrounding Koko and her acquisition of sign language. Her trainers believe that she mastered sign language and is able to effectively communicate. Whereas critics claim that Koko does not understand the meaning of her actions- and simply repeats signs with her trainers because she learned under operant conditioning. As in- Koko’s ability to sign is no different from my dog sitting down when I have a treat in my hand.

I found this article to be fascinating because it says a lot about language possibilities between species and the very core of this experiment says a lot about human nature. I disagree with critics of the Koko experiment who label Koko as being ignorant to watch she is saying. I think Patterson, Tanner, and Mayer arranged the experiment in a way that sign was used to further Koko’s needs or desires. Sign wasn’t used simply for experimenters to explain their actions to Koko. The researchers taught Koko how to sign and then let Koko adapt, manipulate, and use the language to further her own desires. If she wanted food- she could sign “more milk” or “need more”. It’s clear that Koko was deliberate and knowledgeable in her actions because they were often her trying to explain herself. I also think the experiment says a lot about human nature. This project was conducted in the 1980s. It’s very interesting to me that the premise of the experiment was- let’s see if young gorillas are similar to children in learning language. It says a lot about how many experiments are carried out- Koko was held up against the cognitive ability of a child- because that’s what we know. We understand how children respond to learning languages- so comparing it to measured results is easy. This experiment shows our desire to define the animal kingdom in terms of our own species.

Reference: 

Patterson, F., Tanner, J., & Mayer, N. (1988). Pragmatic analysis of gorilla utterances: Early communicative development in the gorilla koko. Journal of Pragmatics, 12(1), 35-54.

Picture: 

http://www.telegraph.co.uk/earth/wildlife/8765172/An-audience-with-Koko-the-talking-gorilla.htmlImage

Proposed Paper Topic

HarryHarlow1

For my final paper, I want to focus on the experiments and discoveries of Dr. Harry Harlow. Dr. Harlow conducted highly questionable experiments on Rhesus macaques in the 1930s. His experiments produced viable results but his methods today are considered unethical. It can be said that Dr. Harlow’s experiments heightened awareness of laboratory animals and lead to the creation of today’s ethic regulatory boards. In my paper I want to look at the reactions of not only today’s scientists but Dr. Harlow’s fellows as well. His experiments were considered slightly radical in the 30s- the difference is there were no ethical boards to stop Dr. Harlow. I want this paper to accomplish two goals- one to examine the methods and experiments of Dr. Harlow (including his motivations and actions upon completion because in some cases he attempted to rehabilitate monkeys that had been subjected to isolation). And I also want to study the ethical ramifications of his actions both during his time and during our time.

harlow

 

Zoo Impressions

I enjoyed myself that the North Carolina Zoo. I was surprised at how expansive the area is. It took me around 30 minutes to reach the Africa part of the park from the North America entrance. My observing experience was a little different- I observed the gorillas with the presence of visitors. Mainly families with small children. In a way I felt like I was observing both the gorillas and the families. It was interesting because most of these families were mothers and their children. And within the Gorilla exhibit were two mothers and their children. I started out not knowing who was who. It was difficult to get close to the board telling you which gorillas was male and which was female. I quickly discovered saw the two infants- Bomassa and Apollo. I noticed a gorilla lying in the right, front corner of the exhibit and one in the far left, front corner. I soon realized Olympia was on the right and Jamani was on the left. When I arrived Bomassa was extremely active, wandering around the rock formation at the front of the exhibit, playing with the hay, trying to incite action from Apollo. Apollo however was trying to rest with Olympia who was resting on her back- always touching at least one of the infants. Jamani was in the left corner, attempting to almost blend into the wall- pushing herself into a small, rather narrow corner. She was not engaging with Bomassa in the beginning. Both females were so lethargic that I wondered whether the warm weather was exhausting to them- but upon realization- gorillas need to rest a lot.

I could tell my presence was somewhat off putting to many of the visitors. A twenty year old- concentrating intently on the gorillas- often blocking the view of babies and small children to see what was happening- all the while scribbling furiously an observation sheet. I was in the way of many pictures. Every time I heard a collective exclamation of joy or shock from a group- I rushed to their side to see what had happened. I was asked constantly if I worked for the zoo or was researching gorillas. It was an odd- but interesting position to be in.

What I liked most about my time was that I was really able to concentrate of the gorillas and see their ordinary behavior while subconsciously doing a small case study on people’s reactions to gorillas. Children naturally called them monkeys. Adult tried- in vain- to correct them and would attempt to explain the difference between gorillas and monkeys. People expressed their shock at how well the mothers took care of their infants- and the close bonds between mother and young. I also had to admit my shock at the relationships between mothers and young. Each mother nursed twice while I was observing and made time to play with or simply hold their infants often. I was surprised at how small the gorilla’s enclosure was. I thought it would have had more room- the elephant exhibit is enormous. It seemed to be that the gorillas would have welcomed more space. Ultimately I had a good time at the zoo. It did however alert me to the backward ways children view zoo animals- and as zoos constantly state their commitment to education- I think this is a problem. Children believe that those are natural habitats. Rarely do parents even explain or read the written aside about the true origins of most zoo animals and that presents a false picture.

 

Dian Fossey Archives

Dian Fossey (1932-1985) was an American primatologist who dedicated her life to studying Mountain Gorillas (Gorilla beringei beringei) in the Rwandan mountains for almost two decades. Fossey was one of the many primatologists influenced and encouraged by Louis Leakey. Leakey was also the mentor of Jane Goodall and established Orangutan Foundation International in Indonesia. Dian Fossey spent her time observing the gorillas, recording behaviors, attempting to understand their personal relationships, and even learning how to gain trust. She actively fought poachers in Rwanda and petitioned the government for stronger laws and enforcement. She dealt with the deaths of her favorite gorillas such as Digit, Uncle Bert, Sweli, and Macho. Fossey was found on December 27th, 1985 murdered in her cabin, presumably by poachers, but it is unknown. Her killer has never been found.

Wake Forest is fortunate enough to have access to the Harold Hayes documents in the Special Collections section of the library. Hayes was fascinated by Fossey and wrote a novel: The Dark Romance of Dian Fossey. Hayes collected countless letters, field notes, and interviews by and about the life of Dian Fossey. What is most extraordinary about the archives are the letters written by Fossey. She wrote so often and to so many people. In some letters she is petitioning for money, describing her work, looking for new help, or simply detailing her life at that moment. She was a very cheeky woman- a lot of her letters to fellow researchers were great because they had both interesting observational information but also personal tidbits and brief windows into her personality.

I reviewed a letter written on March 3rd 1977. She writes to a man named Richard- I was informed in the library that this man is Richard Rombach (a friend and fellow researcher). She discusses how things have been going for her lately, she mentioned difficulty in nailing down a possible applicant interested in working with her. She then lapses into observational notes. Fossey describes that the birth her team had been waiting for had finally happened. The gorilla- called Marchessa- is believed to have given birth on Sunday night. Fossey’s assistant sees the offspring on Monday and describes it as “all pink and very small.” She states that she becomes cranky because the trail route wasn’t properly followed and she wanted afterbirth and blood collected. She then goes back to follow the trail but runs into the mother and child again but realized the mother isn’t Marchessa- it’s Pantsy! She chides herself for not knowing that Marchessa had been mistaken for Pantsy. She observes the baby and the mother. Then Marchessa arrives and she has a baby too! She then realizes the two females have given birth. She runs to each nest and collects the afterbirth and blood- she states that “it’s all too exciting for words.”

I found Fossey’s strict policy about following the trail route and observing every day to be the best part of the letter. She really underlines the importance of observation and field notes. She takes such personal responsibility when the field notes are not taken as if she has failed the gorillas. It really is necessary to observe every day because otherwise- new developments will slip through the cracks. It’s impossible to carefully monitor process if records and observations are neglected or forgotten.

dian-fossey-mountain-gorillas_44342_600x450

Photo: http://www.fromquarkstoquasars.com/wp-content/uploads/2014/01/dian-fossey-mountain-gorillas_44342_600x450.jpg

http://www.biography.com/people/dian-fossey-9299545?page=2

http://wakespace.lib.wfu.edu/handle/10339/36412

http://www.unmuseum.org/fossey.htm

Fossey, Dian. Letters January- March 1977. Dian Fossey Collection: Box 13. Howard T.P. Hayes Special Collections. Wake Forest University, Winston-Salem, NC. Accessed Febuary 25, 2014. Print.

Food and Social Organization

Gathering food requires social interaction and cooperation. Primate must foraging during their waking hours in order to sustain themselves and their social communities. Primates have adapted to particular dietary niches over time and are very much in tune with seasonality. Female primates have a particularly invested interest in food because they need to be nourished enough to sustain either a fetus or growing offspring that relies completely on the mother for food. Adult females are always exerting themselves for their offspring. During pregnancy, they are giving the fetus nutrients through their bodies. Once the fetus is born, females lactate to sustain their offspring. And as offspring grow, females continue to forage for and usually carry their fetuses. According to Strier “Most primate mothers bear most of all of the burden of caring for their infants until they are able to find food and move about on their own” (146).

Lactating is extremely nutrient draining and energy costing for females. As a result, lactating females spend more of their time eating food with high energy contents. In other words they must consume a high quality diet vs. a low quality diet. A high quality diet is defined by rich, easily digestible energy, rich in both protein and nutrients. A low quality diet is poor in nutrients.

Males and females actually have different dietary needs. Males are often heavier than females. Females must ingest enough to sustain their bodies during reproduction. Strier states “Sex differences in diet can be very compelling in highly dimorphic primates. In fact, some researchers have suggested that sexual dimorphism in body size reflects ecological selection pressures favoring the avoidance of feeding competition between the sexes (Selander, 1972; Demment, 1983, Kamiliar and Pokempner, 2008). Dietary difference is evident in both food choices and fallback foods that each sex rely on.

Spacial distribution of food is also an important factor. Valuable primate food resources exist in good patches. High quality foods are found in patchier areas than low quality food like leaves. Seasonality also affect primate food resources. High quality foods are not fully available throughout the year. Many factors affect food availability, a few are closeness to the equator, temperature, and rainfall. They effect the availability of certain foods. Interestingly, dietary switching is very common to primates more common than habitat shift or grouping shifts.

However, primates are very good knowing when to conserve and exert energy. They will travel shorter distances for concentrated food sources because those sources are generally a lower quality. But they will exert a great deal of energy and travel long distances for high quality food which is often widely dispersed and patchy. Finally the use of torpor is another way primates save energy. For example the nocturnal species Cheirogalidae go into daily torpor. They put on fat, lower their temperatures and metabolic rate (Strier). Ultimately, food is an extremely social subject. Whoever forages the food and whoever gets best pick of the food speaks to the sociological structure of groups.  

Image

Strier, Karen B. Primate Behavioral Ecology. Boston: Allyn and Bacon, 2000. Print.

Picture: https://lookfordiagnosis.com/mesh_info.php?term=Cheirogaleidae&lang=1

 

Bonobo Sexuality

PAN PANISCUS

Bonobo society differs greatly from that of chimpanzees. Bonobos have been discovered to be much more free sexually than chimpanzees. However in bonobo society sex has extreme importance. Research has shown that bonobos social systems are based on sex rather than warfare and aggression (Parish 2). It is becoming increasingly apparent that chimpanzees and bonobos, while close species within the same genus, have completely different approaches to social structures, gender dominance, and sexual nature. Parish gives four methods that have created a separate sphere for bonobos. First is that the bonobo should be characterized as a “specialized anomaly” that should be discarded as a model of the last shared ancestor. The next two strategies sit upon the idea that chimpanzees and bonobos should not be referred to in the same context. Finally, Parish questions whether bonobo data contains “contextual biases” there for data collected is not fully reliable (Parish 3).

Bonobo society is known for being female dominant, egalitarian, and focused on sex rather than aggression (Waal). Females are usually granted feeding priority. Males usually locate the food but the females control the access and distribute based on favor (Parish). They can be very influential and often gain the upper hand more than most primates. They form alliances with fellow females and attack the males when provoked. The rank of male primates is determined by their mother’s rank. Bonobos, like chimpanzees, live in fission-fusion societies. The make of the group is fluid and changing sometimes containing many males or many females or a small amount of members. Females are more migratory than males however. The males stay with their natal group where as the females migrate during adolescence (Waal). This means that females are more adapt at dealing with unfamiliar, new usually dominant group members. However once in a group, bonobo mothers are extremely important. Males remain attached to their mothers both emotionally and physically. They rely on maternal protection and they remain constantly close- following their mothers through habitats. While male chimps fight independently and form alliances with other males, bonobos are very centered around female dominance.

Bonobos and chimpanzees social structures can reveal a lot about human society. But personally I think the value of studying their societies goes beyond simply applying it our society. These structures speak to how diverse social structures can be between close species. Bonobos were originally called “pygmy chimpanzees.” Now we are discovering so many formally held beliefs about primates are not valid.

Parish puts it best. “Until recently, primatology textbooks described gorillas as terrestrial and folivorous, gibbons as living in “monogamous” nuclear family units, and orangutans as solitary and asocial. Yet recent observations reveal that some gorilla populations are arboreal and frugivorous, that individuals in some gibbon groups engage in extra-pair copulations and form flexible living arrangements involving multiple adult individuals of the same sex, and that orangutan females in some populations coalesce and socialize when ecologically feasible” (2). This line demonstrates just how our knowledge is still growing about primate societies. We need to be wary of declaring facts in stone because ultimately these are complex societies and need to be treated as such.

Works Cited

De Waal, Frans BM. “Bonobo Sex and Society.” Bonobo ( ‘Pygmy Chimpanzee’ ) Sex and Society. Scientific American, Mar. 1995. Web. 20 Feb. 2014.

Parish, Amy R., Frans B. M. De Waal, and David Haig. “The Other “Closest Living Relative”: How Bonobos (Pan Paniscus) Challenge Traditional Assumptions about Females, Dominance, Intra- and Intersexual Interactions, and Hominid

photo cred: http://gifts.worldwildlife.org/gift-center/Images/large-species-photo/large-Bonobo-photo.jpg

Orangutan Vocalization

I chose to review an article written by the Orang Utan Republik Foundation (OURF) dealing with the Orangutan’s diverse vocalization- focusing specifically on the long call. “[Orangutans] have a surprisingly varied vocal repertoire, with geographic differences in size, development and acoustic structure, indicating a form of language in orangutan society and cultural variations between populations” (OURF). The most famous form of vocalization is the long call. Flanged males or orangutans that show the secondary sexual characteristics of maturity preform long calls. Long calls last around two minutes and can be intercepted several kilometers away. According to OURF, the call is the loudest acoustic signal in the orangutan vocal repertoire. Several forms are possible and the call is increased by the cheek pads and the laryngeal chambers of the males which help reverberate the sound further and last longer. Primatologists are not certain what the purpose of the long call is but OURF believes that its function is a spacing mechanism and mating strategy.  Orangutans live in overlapping, close range homes. Visibility is often a problem due to canopies and as a result they need vocalizing to help distinguish where one another are. A powerful long call helps flanged males indicate their position in relation to other males. Responses to the long call depend on the other males’ sense of dominance. Longer ranked males tend to move away from aggressive long calls. Potential rivals are warned away from the area as well.

45med

However the long call is also utilized for mating practices. Long calls are often produced when flanged males are without a female. Females then respond to the calls or even coordinate their ranging patter with the locally dominate flanged male. OURF supports this claim with research from primatologist Dr. Roberto Delgado. “Current data for the role of long calls as a female attraction function are more extensively studied in Sumatra, where research has shown that females selectively approach after long calls by the current dominant male, rather than those of non-dominant males, and spend 90% of their time in earshot of the dominant flanged male, as opposed to the 70% of their time spent in audible range of lesser status flanged males.” Studies show that long calls vary geographically and from orangutan to orangutan so it’s impossible for there to be a “standard long call.” Orangutan vocalization is a subject that is growing in research but difficult to follow because of the semi-solitary lives of orangutans.

Article: http://www.orangutanrepublik.org/become-aware/orangutan-specifics-40237/vocal-repertoire

Picture: http://pin.primate.wisc.edu/factsheets/entry/orangutan/behav