User:Cem022591/sandbox

Overview

   Animal co-opted sexual behavior is sexual activities animals participate in that do not lead to the reproduction of the species. Though procreation continues to be the primary explanation for sexual behavior in animals, recent observations on animal behavior has given alternative reasons for the engagement in sexual activities by animals. The general explanation for sexual activity in the animal kingdom is now being disputed with recent observations, such as a mature male fruit fly courting immature male fruit fly.
   Animals have been observed to engage in sex for social interaction, demonstration of dominance, aggression relief, exchange for significant materials, and sexual stimulation.1 3 General examples of sexual activities that have recently been observed are genital stimulation and acts of affection. There have also been observations of animals engaging in homosexual behaviors. 

Social Interaction/ Bonding

    Lions are known to engage in sex to create bonds and interact with each other. Lions live in a social group known as a pride that consists of 2-18 females and 1-7 males. The females found in these prides were born into the pride. The males enter the pride from other prides.  The success of reproduction for each individual lion is dependent on the number of male lions found in their social group.  Male lions create coalitions and search for prides to take over.  Successful coalitions usually have created a strong bond with each other and will take over prides. Once wining in a competition, all current males in the pride will be kicked out and left to find another pride. While in search for another pride these males will often engage in sexual behavior with each other; creating a strong bond in this new coalition created.     
    Sex is a basic form of communication in bonobos’ life. It seems to infuse everything from simple expressions of affection to the establishment of dominance. Female bonobos have been observed to engage in sexual activities to create bonds with dominate bonobos. Having created this bond with the male, they will share food with each other and not compete with each other.  All members of the group are potential sex partners, males participate in sexual activity with other males, as though females with other females. These bonds are made between females are for protection against male bonobos. If a male bonobo attempts to harass a female bonobo, the other females will help the female defend herself because of the strong bonds they have with each other.<ref name="Bagemihl"Bagemihl, B. Biological exuberance: Animal homosexuality and natural diversity. New York, NY : Profile Books Limited (1999)</ref>

Aggression

         Several species in the animal kingdom turn to sexual activity as a way to solve a disagreement. Bonobos are one species notoriously known for using sexual behavior to relieve their aggression with each other. 3 Sex is part of bonobo’s daily routine and social life. Unlike other primates aggression is substituted with sex. Sexual activity in bonobos is very high, yet the rate of reproduction is the same as a chimpanzee. 1
    In a study concentrated on primate aggression, researchers wanted to observe primates in conflict. How primates coped and resolved conflicts was a main concern in this study. Researchers stated that after primates participated in a heated, physical fight; both primates involved in the fight would hug and have a mouth-to-mouth kiss. This action was considered as a demonstration of affection and reconciliation. 1
  Sexual interaction has also been witness in female bonobos to avoid aggression. When hungry, the female bonobo will approach a male bonobo and engage in sexual activity to avoid aggression. After their quick sexual activity, the female will bravely take a portion of the male’s food. The male will not demonstrate any form of aggression towards the female. 3

Proximate causes

      Awareness in species is difficult to determine. Learned behaviors that have been demonstrated in laboratories have provided good evidence that animals have instinct and a reward system. The behavior that laboratory animals demonstrate a mental experience where the animals instincts tell it if is carries out a certain action, it will then receive what it needs.12  For example, the lab rat will push the lever because it knows food will fall out of the hole in the wall. It doesn’t need awareness, but it does seem to work on a reward system. The lab rat learned the action needed to be fed.
   Studies of the brain have proven that pleasure and displeasure are an important component in the lives of animals.10  It has been established that the limbic neural mechanism that generates reactions are very similar across all mammals. Many studies have concentrated on the brain reward system and how similar it is across mammals.10 Through extensive research, scientist have been able to conclude that the brain reward system in animals is extremely similarly to that of humans. The mechanism of core pleasure reaction is significantly important for animals and humans. 10 

Case study

  In a case study, female Japanese macaques were studied to find evidence of possible female copulatory orgasms. Through the study the frequency of orgasms did not correlate with the age of the Japanese macaques or the rank. Researchers observed that the longer and higher number of thrust with the pelvic, the longer copulation lasted. There was an orgasmic response in 80 of the 240 Japanese macauques studied. 14
   Evolutionary principles have predicted that the reward system is part of the proximate mechanism underlying the behavior. Being that animals have the brain reward system they are motivated to perform in different ways by desire and reinforced by pleasure.10  Animals establish security of food, shelter, social contact, and mating because proximate mechanism, if they do not seek these necessities they will not survive.11 
   All vertebrates share similarities in body structure; they all have a skeleton, a nervous system, a circulatory system, a digestive system and excretory system. Similar to humans, animals also have a sensory system. The sensory system is responsible for the basic five senses from touch to tasting. Most of the physiological and biochemical responses found in animals are found in humans. Neurophysiologists have not found any fundamental difference between the structure and function of neurons and synapse between humans and other animals.12     

 Case study
     Recent studies using Positron Emission Tomography (PET) and Magnetic Resonance Imaging (MRI) has provided evidence proving that chemical changes that occur with emotions are similar between humans and animals. In a study comparing guinea pigs and humans, it was determined that the distress experienced by offspring separation in a guinea pig and a human going through depression activates the same region of the brain. The opiate receptor was also examined, allowing observation of the pleasure stimuli. In the procedure both human and a rat had their receptors blocked with a certain drug. Once receptors were blocked, both the rat and the human were exposed to pleasurable food, but both were disinclined to eat the food. 7 

Types of non-penetration sexual activity

   Engagements of sexual activities during non-breeding seasons have been observed in the animal kingdom.  Dolphins and Japanese macaques are two of the many species that engage in sexual activities that do not lead to fertilization. Great varieties of non-copulatory mounting are expressed in several species. Male lions engage in mounting with other male lions, especially when in search for another pride.5 The varieties of mounting include mounting without erections, mounting with erection but no penetration, and mounting from the side. 
   Expressions of affection are displayed in the animal kingdom as well. Affectionate behaviors do not include penetration or genital rubbing, but are still seen as a manner of sexual behavior.  An affectionate activity can be as simple as licking.3 Male lions are known for head rubbing, bats engage in licking, and mountain sheep rub horns and faces with each other.8  Animals have also engaged in kissing, touching of noses, mouths and muzzles have been witnessed in African elephants, walruses, and mountain zebras.4 Primates also engage in kissing that is incredibly similarly to human display of kissing. Chimpanzees have full mouth-to-mouth contact, and bonobos kiss with their mouth open and mutual tongue stimulation. 3 There are a variety of acts to show affection such as African elephants intertwining their trunks, giraffes engaging in “necking”, and Hanuman Langurs cuddling with each other in a front to back sitting position.
    Non-penetration genital stimulation is very common throughout the animal kingdom. Different forms of self and partner genital stimulation have been observed in the animal kingdom. Oral sex has been observed throughout the animal kingdom, from dolphins to primates Bonobos have been observed to transition from a simple demonstration of affection to non-penetration gentile stimulation.8 1Animals perform oral sex by licking, sucking or nuzziling the genitals of their partner. 8 13 Another form of genital stimulation is masturbation. Masturbation is widespread throughout mammals for both males and females. It is less common in birds. There are several techniques, in which animals engage in masturbation from using paws, feet, flippers, tails, and sometimes using objects like sticks, pebbles, and leaves.13

Homosexuality

   Homosexuality has also been observed in over 400 different species in the animal kingdom.9 Animal homosexuality spectrum is complex compared to human homosexuality; by definition homosexuality is a sexual attraction or relationship with a member of the same sex. Homosexuality can be evolving penetration or non-penetration.   The different examples are homosexual pair-bonding, homosexual parenting and homosexual acts of affection. Homosexual behavior is certainly a sexual behavior animals engage in that will not result in procreation. Engaging in homosexual behaviors have allowed species obtain different benefits such as, gaining practice, relieving tension, and experiencing pleasure.11 8 3

Pair-bonding in homosexuality

   Homosexual pair-bonding can be established several ways; two of the main ways are pair bonding as partners or as companions.13 As partners, both animals will engage in sexual activities with each other. In companions bonding, sexual engagement is not necessary in the relationship. This form of homosexuality is more of a partnership and friendship; they spend all their time together. More than 70 species of birds engage in one of these two bonding.13  

Homosexual parenting

   Homosexual parenting is very common; especially in birds.13 Homosexual pairs have better skills and larger nests than heterosexual pairs. Homosexual pairing can occur different ways, one example would be two female animals with offspring coming together and helping each other raise their offspring.13 

References

  1.	Waal , F.  Bonobo sex and society. Scientific American, 272 (1995) 

2. Dukas, R. Causes and consequences of male–male courtship in fruit flies. Animal Behaviour 80, 913–919 (2010). 3. Dubuc, C. Alan F. Dixson: Primate Sexuality: Comparative Studies of the Prosimians, Monkeys, Apes, and Humans, 2nd Edition. International Journal of Primatology 34, 216–218 (2012). 4. Bailey, N. W. & Zuk, M. Same-sex sexual behavior and evolution. Trends in ecology & evolution 24, 439–46 (2009). 5. All, A. M. & Terms, J. The Evolution of Sex-Biased Dispersal in Lions Author ( s ): Anne E . Pusey and Craig Packer Reviewed work ( s ): Published by : BRILL Stable URL : http://www.jstor.org/stable/4534604 . 101, 275–310 (2013). 6. Cooperation, I. & Pusey, A. E. competition. 130, 636–642 (2013). 7. Berridge, K. C. & Kringelbach, M. L. Affective neuroscience of pleasure: reward in humans and animals. Psychopharmacology 199, 457–80 (2008). 8. Balcombe, J. Animal pleasure and its moral significance. Applied Animal Behaviour Science 118, 208–216 (2009). 9. Erickson, B. Queer Ecologies Sex, Nature, Politics, Desires. Indiana University Press (2010). 10.Balcombe, J. Pleasurable kingdom:animals and the nature of feeling good . New York, NY Macmillan (2006). 11. Hedricks , A., & Temeles , E. The evolution of sexual dimorphism in animals: Hypotheses and tests. Cell Press , 4 (1989). 12. Griffin, D. Question of animal awareness: Evolutionary continuity of mental experience. New York, NY : William Kaufmann Inc (1981). 13. Bagemihl, B. Biological exuberance: Animal homosexuality and natural diversity. New York, NY : Profile Books Limited (1999). 14. Troisi, A. Carosi, M. Female orgasm rate increases with male dominance in Japanese macaques. Animal Behaviours 56. 1261-1266 (1998).