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Homosexuality in Animals

JJ's picture
Homosexuality in Animals
            While human observations have long noted homosexual behavior in animals, more recent studies have focused specifically on homosexuality and its causes and effects amongst animal species. The importance of diversity- including homosexuality- within a species has been long debated; Darwin thought of diversity as having numerous possibilities for a species but contrarily sometimes believed that it left more chances for impurities and "bad" genes to be passed on. Several examples exhibit various potential reasons for the development of homosexual behavior in animals. Homosexuality in ape and monkey species is perhaps the most recognized one, but there is a huge variety of examples, including some lizard species and sheep.
            When considering aspects of homosexual behavior in animals, I chose three main questions on which to focus. The first, and perhaps most broad, relates to general biological interest: What is relevant about this topic and why should we as everyday scientists care? With the second I focused more on the effects: What is the usefulness to a particular animal or species of being homosexual or behaving in homosexual ways? With my third question I tried to tie the topic into human issues: What are the practical problems related to homosexual behavior in animals, particularly those used by humans?
            The idea of some animals being “predisposed” biologically to homosexual tendencies is relevant to the current debates in human diversity. Scientists have done tests on species such as birds and sheep to see what may push them to have a same-sex partner. Significant portions of rams, up to 16 percent, never mate with a female during the breeding season. (1). Despite having choice and free-range with the females, the males do not mate with them or instead, mount males. I think that the crucial part of this research is that the male is given every opportunity and a natural environment to determine whom he mates with. 
Added to research is the more biological or experimental side. Scientists have started to make new observations about biological reasons for homosexuality. Certain hormones, castration, and prevention of enzymes may cause animals to prefer their own sex. Injecting pregnant females with specific hormones “greatly increases the mothers’ odds of producing homosexual offspring” (1). This is a concrete new story that I am willing to believe points directly to a legitimate chemical reason for animals (and hence humans) to have homosexual tendencies. If a hormone, surgical procedure, or alteration of some biological aspect of an animal can change or predispose it towards its own sex, that legitimizes the idea of sexual preference being within one’s brain and out of the range of being a choice. The idea of choice is crucial to human thoughts on sexuality as it has been common to claim that homosexuals make a choice to be gay. The research on animals, while not “proven” on people yet, leads me to understand that sexual preference is much more biological than may have been previously thought by both scientists and average people. 
            Other examples show more of the potential benefits for animals that are homosexual or practice homosexual behaviors. In the case of the purple swamp hen, up to 10 percent of the population mates or attempts to mate with its own sex (2). This could be beneficial in multiple ways. The female-female mating could possibly determine the number of eggs the female lays; also, the body language given in mating might help to decrease aggressiveness amongst the flock (2). In a situation such as this, the homosexual behaviors are not only natural but also help the species to regulate its population size and general attitude. 
            In a much more peculiar case, scientists studied the all-female species of whiptail lizards. Although the species clones itself and thus requires only one gender of animal, they continue to undergo a courtship process that is not only as intricate as the male-female mating but also leads to an increased production of eggs. The species is also much more peaceful than similar species with two genders (2). I see this as a very beneficial relationship: the lizards live more peacefully and cooperatively while increasing their population at a greater rate than they would by themselves. By maintaining important rituals found in generally heterosexual lizards, I find it hard not to believe that the female lizards really feel a connection that allows them to better their communities.
            Despite the more positive aspects of homosexuality in animals, there are negatives visible mainly to humans. We use, eat, and raise animals in mass. There are huge economies dependent on the amount of animals produced, so an animal that does not mate with the opposite sex to produce young is a detriment to the farm and economy. Farmers need animals that produce and in this way homosexuality is clearly not something that a human would be willing to accept. Homosexual rams, for example, can store similar amounts of estradiol in their systems, something found in female rams (1). For practical human purposes, being able to find out their rams’ preferences could help their success in breeding. As more research comes out and people become more open to the idea of homosexuality in both animals and people, I would imagine that scientists would attempt to focus much more on the biological and chemical differences that determine animals’ sexuality.
            Aside from human uses, homosexuality does not appear to be detrimental to a species. I have pointed out some of the benefits it may have for particular species. The fact that it can help a population be more peaceful, productive, and potentially produce more offspring is very beneficial for any animal. Aside from the above-mentioned possible benefits of homosexuality in animals, I think that it could also be another evolutionary method of keeping a population under control. That is something I think should be pursued further: if a population is growing too much or suffering from lack of resources, do some animals display more homosexual behaviors? I would like to see the scientific community continue to research on the reasons for homosexuality that can be found in the brain. If scientists could continue making new observations about specific chemicals that create homosexual behavior, I believe that it would help adjust the story and stigma many humans hold against our own kind who identify as homosexual.
(1) “Animal’s Fancies”, Tina Alder, Science News

(2) Evolution’s Rainbow, Joan Roughgarden, University of California Press 


Michael S. Teruya's picture

animal homosexuality

Among Animals, Homosexuality Is a Waste Product

The survival instinct in animals is basically accepted as survival of the fittest, or based on natural selection. The predominate instinct falls upon males who fight for the right to reproduce. In the female sector, instinct may deviate in other more destructive ways such as female dogs killing a pup that is touched by a human. They don't know what they are doing.

Once the fittest male earns the right, the rest of the male population are considered waste product. Their instinct is frustrated and are allowed to waste away in anomalous behavior. Whereas, natural instinct remains intact among the stud and breeders.

In humans, being intelligent, our survival is different. We accommodate the belief that there is a woman for every man and a man for every woman, so there is no waste product. We also have tribal culture and species pride, in that our instinct is one of perpetuating intelligence and awareness, so our survival instinct also includes culture, religion, social order, and compassion: our way of life as well as existence.

The conclusion is that there is no homosexuality in nature as an alternative lifestyle. Any anomaly and deviation is a waste product. In humanity, singleness is a choice, and one is either beneficial or not, and society determines the virtue or vice.

Paul Grobstein's picture

learning from homosexuality in other organisms

It would, I think, be worth further exploring the question of benefits gained from homosexual behavior in biological systems generally, and perhaps using that as a foundation for asking whether similar benefits are gained in humans.  I'm less sure its useful to know more "about specific chemicals that create homosexual behavior."  Yes, chemicals can alter all sorts of behavior, including sexual preferences, and yes, that tends to imply something going on in the brain.  But among the things that go on in the brain is "choice," so its not entirely clear to me what is gained by saying that sexual behavior can be influenced by influences on the brain.