Thursday, January 10, 2013

Homosexuality and Bisexuality in Female Bonobos




            Field research on bonobos started in the 1970s, making this a relatively new field. The bonobo was discovered by science in 1929, and was given the Latin name Pan paniscus, or Diminutive Pan. Bonobos were also known as pygmy chimpanzees. The archaic term for the chimpanzee, Pan satyrus, would have been a much better name for bonobos, since a Satyr was a lustful creature in Greek mythology (de Waal, 32).

            Bonobos share about 98% of their DNA with humans (de Wall, 32). Bonobo behaviour is fascinating because we hope that it may explain how we, as a species evolved, as well as make more sense of our own behaviour. Oftentimes we humans find the behavior of our own species perplexing as well.

            Yes, there has been a lot of talk within the scientific community of bonobos being peaceful, and how we humans, as a species, could learn how to “Make Love Not War” like bonobos do, but all is not as it seems. Bonobos have also been found to exhibit more aggression in relation to food than chimpanzees (Stanford, 407). Just recently, researchers in Salonga National Park have observed bonobos hunting and eating immature Redtail (Cercopithecus ascanius), Black Mangabey (Cerccebus aterrimus), and Wolf’s Guenon (Cercophithecus wolfi) monkeys. Researchers believe that both bonobo and chimpanzee hunting is relatively rare and that observation has to be at close-range and fairly frequent in order to detect hunting behaviour. Unlike chimpanzee hunting parties, which consist of nothing but males, the bonobo hunting parties which were observed consisted of mostly females: 4 female, 1 male; 3 female, 1 male; 5 female, 2 male; 3 female, 2 male; 4 female; 2 male. (Surbeck, R906). These new findings indicate that there is more research which has to be conducted in an effort to reassess our perception of bonobos.

            Bonobos live in a fission-fusion society, which is characterized by small groups being formed for foraging purposes, which join with larger groups within the community (Hohmann, 113). Bonobo society is matriarchal, meaning that women are the dominant sex in your society (Stanford, 404). The oldest females tend to occupy the highest-rankings in bonobo society (Stanford, 402). Females appear to have stronger bonds with other females than males do with other males. This is different from what we know of chimpanzees, where males are the dominant sex and have stronger bonds with other males than females have with each other (de Waal, 36). 

            Bonobo sexuality is complex, as well. Bonobos stare into each others eyes during coitus and engage in face-to-face positions one out of every three times in the wild (de Waal, 34). Female bonobos engage in Genitogenital rubbing (G-G rubbing) with other females. G-G rubbing consists of two females embracing each other in a face-to-face position and rubbing their engorged genitals together (Hohmann, 108). G-G rubbing is the most common form of sexual behaviour in bonobos, and is absent in chimpanzee sexuality (Stanford, 407). Female bonobos have a rather large and well-developed clitoris and clitoral penetration has been observed (Bagemihl, 270).  The average sexual contact between females lasts about 13 seconds (de Waal, 34).

            For the longest, it was believed that humans were the only primate who engaged in a face-to-face sexual position, that is, until we observed bonobos in face-to-face positions. Bonobo females have a more ventrally positioned vagina than chimpanzees do, thus making such a position possible. It was once believed that this positioning of the vagina, face-to-face copulation, and female orgasm were all results of bipedalism (Lloyd, 69). Although bonobos have been observed to walk upright, thus enabling them to be more effective at carrying food, they are still not considered to be fully bipedal (Nova/BBC).

            As far as your chances with the ladies are concerned, there is much evidence of bisexual behaviour within bonobos of both sexes, so it depends on which part of an estrus cycle the female is in and if she wishes to mate with a male. One study has shown that the female rate of copulation with males increases if the size of the mixed-sex group she travels with increases (Hohmann, 114).  roup size varies seasonally depending on availability of food (Hohmann, 117).

            There are two male equivalents to G-G rubbing: Penis-fencing, in which two males hang from a branch and rub penises together while in a face-to-face position; and Scrotum rubbing, which is similar in nature to G-G rubbing (de Waal, 34). Penile penetration has not been observed in male bonobo homosexual activity (Bagemihl, 272).

            Laboratory experiments conducted on female Stump-tailed Macaques (Macaca arctoides) show that they experience orgasm (de Waal, 34). Researchers have also observed orgasmic muscle spasms in female bonobos during G-G rubbing (Lloyd, 128).

           

            Female G-G rubbing serves many purposes in bonobo society. First of all, it helps to alleviate tensions between individuals. For example, if food is scarce, groups of bonobos foraging run the risk of getting aggressive with each other, sex is used as a way to calm tensions. Genital contact is initiated by lower-ranking individuals: they solicit sex from higher-ranking individuals. It is interesting to note that the higher-ranking individuals are in closer proximity to food, thus, lower-ranking individuals have to be close to the higher-ranking bonobo in order to have sex, thus increasing their own proximity to the food (Hohmann, 115).

            Another purpose for G-G rubbing is reconciliation. If there is a have an agonistic encounter between two individuals, the lower-ranking individual will solicit the higher-ranking individual for sex after such an encounter. As a form of conflict resolution, it appears to be quite effective (Hohmann, 112).

            The last use of G-G rubbing is for expression of social status. Subordinate females who solicit sex from a dominant female assume the mountee (bottom position), and the higher-ranking female is the mounter (top position) (Hohmann, 115).

            Bonobo sexuality is fascinating because it varies in many different ways: sexual positions, sexual orientation, and the fact that bonobos engage in sex for non-reproductive reasons (tension regulation, reconciliation after conflicts, and as an expression of social status). This difference distinguishes bonobos from many other species in the animal kingdom who only engage in sex when they are in heat or estrus. Bonobos, like humans, engage in sex year-round and for a myriad of reasons. Bonobo research is a new area of study. The fact that we just discovered that bonobos kill and eat other monkey demonstrates that we are still in the dark about their behaviour and society. The fact that we looked to bonobos to convince us that peaceful cohabitation is and can be natural, speaks volumes about how we as a species hope to find an answer to our own violent behaviour.

            Humans look to our nearest primate relatives (bonobos and chimpanzees) to answer our questions about human nature. I suspect that, as any study of behavior has shown, for every question that gets answered, ten more questions will appear to take its place.


Origins and Meanings of the Latin Scientific Classifications

Black Mangabey (Cercocebus aterrimus)

Ater (Latin) black, hence aterrimus (Latin) very black. Inhabiting forests of southern Congo (Gotch, 517).

 

Red-tailed Monkey (Cercophithecus ascanius)

Ascanius was the legendary son of Aeneas and Creusa in Greek mythology. This monkey is olive-green with a red tail living in a small region in western Africa (Grotch, 519).

 

Pygmy Chimpanzee (Pan paniscus)

-iscus (Latin) diminutive, suffix, ‘little Pan’: another common name was Dwarf Chimpanzee. The name chimpanzee is from a Zaire native name kimpenzi (Grotch, 523)

 

Stump-tailed Macaque (Macaca arctoides) formerly speciosa

Arktos (Greek) a bear –oides (New Latin), from eidos (Greek) apparent shape, form; ‘bear-like’; This monkey is very hairy and heavily built with a stumpy tail about 2 in
(5 cm) long. Inhabiting south-east Asia (Grotch, 516).


References Cited

Bagemihl, B., (1999). Biological Exuberance: Animal homosexuality and Natural Diversity, St Martin’s Press: New York, pp 269-275.

 

BBC documentary on Youtube, http://www.youtube.com/watch?v=eubDSQrFako

 

Grotch, A. F., (1995) Latin Names Explained: A Guide to the Scientific Classification of Reptiles, Birds, and Mammals. Facts on File, New York, pp 515-523.

 

Hohmann, G. and Fruth, B., (2000). Use and Function of Genital Contacts Among Female Bonobos. Animal Behaviour, 60, pp 107-120.   http://www.eva.mpg.de/primat/pdf/AB-paper-July-00.pdf

 

Lloyd, Elisabeth A., (2005). The Case of the Female Orgasm: Bias in the Science of Evolution. Harvard University Press: Cambridge, MA, pp 69-129.

 

Nova: The Bonobo in All of Us. Video. http://www.pbs.org/wgbh/nova/nature/bonobo-all-us.html

 
Stanford, Craig B., (1998). The Social Behavior of Chimpanzees and Bonobos: Empirical Evidence and Shifting Assumptions. Current Anthropology. Vol 39, N 4, Aug. – Oct. 1998. http://jstor.org/pss/3031103

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