Recent research has found that homosexual behavior in animals may be much more common than previously thought. Currently, homosexual behavior has been documented in over different animal species worldwide. Yet another example is lizards of the genus Teiidae, which can copulate with both male and female mates. Biologists Nathan W. Bailey and Marlene Zuk from the University of California, Riverside have investigated the evolutionary consequences and implications of same-sex behavior, and their findings demonstrate benefits to what seems to be an evolutionary paradox.
Loving this. Namespaces Article Talk. It's not clear whether the same thing happens in aniimals sheep, and if LeVay's explanation is right it probably doesn't. Researchers aren't searching for one genetic marker or one cause but a combination of factors that give rise to certain behaviours under specific circumstances. The genetically modified flies displayed drastically different sexual patterns, such as females engaging in active courtship, males becoming sexually passive, and male fruit Homo sexuality in animals attempting to mate with other males. Resko, John N. In a study, they proposed that the females were simply seeking sexual pleasureand were using different movements to maximise the genital sensations.
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Males produce alarm pheromones to reduce such homosexual mating. Having evolved with no natural predators, the birds have no fight-or-flight instinct — you Hot grannies home videos basically go right up to one and grab it. Yet, this list lacks detailed descriptions, and a more comprehensive summary of its prevalence in invertebrates, as well as ethology, causes, implications, and evolution of this behavior, remains lacking". Retrieved 13 November In the context of sexuality, lesbian refers only to female homosexuality. Palmer, Stanley M. June 10, This seems quite different from all the other cases of homosexual behaviour, because it is hard to see how it could possibly benefit the males. And only this month, President Bush vowed to continue his bid to ban gay marriages after the Senate blocked the proposal. They're gay. Measuring the prevalence of homosexuality presents difficulties. The article also referred imprecisely to the referencing of a book about the Homo sexuality in animals in a Supreme Court case that overturned a Texas sodomy law.
In its effort to present homosexuality as normal, the homosexual movement 1 turned to science in an attempt to prove three major premises: 1.
- Homosexuality is romantic attraction, sexual attraction , or sexual behavior between members of the same sex or gender.
- Lots of animals engage in homosexual behaviour, but whether they are truly homosexual is another matter entirely.
- All rights reserved.
- The Laysan albatross is a downy seabird with a seven-foot wingspan and a notched, pale yellow beak.
- Andrew Blackstone.
Imperial researchers are using a new approach to understand why same-sex behaviour is so common across the animal kingdom. In , a team of scientists set off on the Terra Nova Expedition to explore Antarctica. He chronicled the animals' daily activities in great detail. In his notebooks, he described their sexual behaviour , including sex between male birds.
However, none of these notes would appear in Levick's published papers. The last remaining copy was recently unearthed providing valuable insights into animal homosexuality research.
But forays into animal homosexuality research long predate Levick, with observations published as far back as the s and s. More than years later, research has moved past some of the taboos those early researchers faced and shown that homosexuality is much more common than previously thought.
Same- sex behaviour ranging from co-parenting to sex has been observed in over 1, species with likely many more as researchers begin to look for the behaviour explicitly. Homosexuality is widespread, with bisexuality even more prevalent across species. Researchers are now going beyond just observing it though, with researchers at Imperial leading the way in unravelling how, and why, homosexuality is found across nature.
With this behaviour seen across species from birds and insects to reptiles and mammals — including humans — researchers are trying to understand why. In the past, homosexual behaviour was often ignored because it supposedly contradicted Darwin's theory of evolution.
Scientists argued homosexuality was a sort of 'Darwinian paradox' because it involved sexual behaviour that was non-reproductive. Recent evidence however suggests homosexual behaviour could play important roles in reproduction and evolution. Savolainen is a world-renowned evolutionary biologist who approaches many of the same questions Darwin did, but from a contemporary perspective.
Savolainen's contributions range from solving Darwin's "abominable mystery" of flowering plants to elucidating how great white sharks evolved to be super-predatory fast-swimmers.
Savolainen explains: "I tackle big evolutionary biology questions. It doesn't really matter what organism, at the end of the day it's all about how genes have evolved either to produce a species or a new behaviour.
The overarching aim of his lab can be summed up with the saying: "Nothing in biology makes sense except in the light of evolution. Savolainen has turned this philosophy to 'Darwin's paradox'. In , Savolainen started some work on animal homosexuality, beginning with a chapter on the Evolution of Homosexuality. Since then, he has assembled a collaborative team of researchers to examine the question through field work, genomic sequencing and new theoretical models. It will be his second of many months-long trips to observe rhesus macaques in the wild.
Female homosexuality has been well studied in Japanese macaques, but Clive's research would examine how homosexual behaviour differs in males and across environments. Clive explains: "Behavioural studies take a long time especially for these unpredictable and infrequent behaviours, which includes almost all sexual behaviours. You have to do a lot of sitting around and watching while also being quite alert.
It takes quite a lot of effort to recognize these individual primates. In one social group I have to recognize males individually. Before beginning his Ph. He noticed mounting between male gorillas, though that was not the main focus of his research at the time. I can give you papers on beetles, spiders, flies, fish, flamingos, geese, bison, deer, gibbons, bats — loads of bats, bats get up to all sorts," he says. It's early days for the Imperial research team.
Recording homosexual behaviour in the wild and collecting blood samples are the first steps for Clive; the next is sequencing DNA to search for connections between the behaviour and genetic markers. In there was a media frenzy over the discovery of the 'gay gene'. This idea stemmed from a study showing a correlation between genetic marker Xq28 and male homosexuality, although there were statistical uncertainties about some of the findings.
Scientists have successfully modelled other complex or polygenic traits like height. There is not a single 'tall' or 'short'. Instead, height is determined by changes across hundreds of genes in combination with environmental factors. To understand what gives rise to complex traits and behaviours, researchers must identify where the genetic changes take place and what underlying processes are driving them.
Then they can see what this should look like in the real world. The biological and hereditary factors of homosexuality are most certainly not tied to a single gene.
Researchers aren't searching for one genetic marker or one cause but a combination of factors that give rise to certain behaviours under specific circumstances. To create models of homosexuality, Savolainen recruited Ewan Flintham as a Ph. Flintham previously worked on models for speciation— the formation of new and distinct species in the course of evolution—as well as sexual behaviour in fruit flies.
He says: "We have the capacity to model complex behaviours and pull on massive amounts of data. However, creating a complex model isn't beneficial unless it is modelling a useful concept.
There are many theories about why homosexuality is important for reproduction and evolution. Savolainen has outlined some leading models. One is the "bisexual advantage" model where animals with a more fluid sexuality are more likely to reproduce. Savolainen's lab looks at a range of sexual behaviours from strict heterosexuality to homosexuality. Bisexuality may be "an evolutionary optimum phenotype in many species, including humans," according to Savolainen's review.
Other models consider whether a gene is beneficial for a specific sex. For example, if the gene were 'feminizing' in the sense that it would lead to females having more offspring so it would be passed on in spite of being disadvantageous for a male's own reproduction, i.
Meanwhile, others posit that homosexuality could also play a role in evolution through co-parenting or helping to raise relatives' offspring. These explanations are not exclusive of one another, and it is likely that a combination of factors are important for the evolution of homosexuality. With these new models, researchers can test many theories in combination and vary the data inputs accordingly.
The "golden standard" would use the original genetic and behavioural data from the macaque field work and fit them to different theories to see how each could be applied to other populations and animals.
The primates Savolainen's lab is currently studying are of course closely related to humans. Studying non-human primates is helpful because it provides clearer data and separates the behaviour from culture while at the same time offering new insights on human sexuality and evolution.
His previous research examined how body-to-limb ratio makes men more attractive. In Savolainen's lab, he's taking a broader and more technical approach. He will create 3-D face models of couples to compare shape, structure, and proportions.
Ultimately, the project will combine questionnaires, facial modelling and genetic sequencing to examine similarities between couples and investigate whether mate-choice decisions are being driven by considerations of biological or social compatibility.
Importantly, this will include exploration of homosexual partners in the hope of understanding different mate-choice strategies in reproductive and non-reproductive contexts. Versluys is currently recruiting heterosexual and homosexual couples among Imperial students and staff for his research. If you would like to know how similar you and your partner are or would just like 3-D models of your faces , please get in touch with him at tmv ic.
Versluys says: "Homosexuality is still something that's not always well understood among the scientific community and maybe even more poorly understood among the general population. It's currently being reframed, in our lab and elsewhere, as a normal behaviour rather than something that's abhorrent or problematic. The hope is that as homosexuality is better understood, research will dispel people's misconceptions.
However, many of the historical cultural challenges persist. And despite the acknowledgement of how widespread homosexuality is in nature, researchers have to contend with a dearth of research that should have been built up over decades. Savolainen explains: "It's still risky and unusual research that is difficult to support through traditional funding routes.
We're looking for organizations or individuals that believe in this research and are willing to take that risk. Vincent Savolainen et al. DOI: Thomas M. Versluys et al. The influence of leg-to-body ratio, arm-to-body ratio and intra-limb ratio on male human attractiveness, Royal Society Open Science More from Biology and Medical.
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Marc; Vilain, Eric; Epprecht, Marc Pan American Health Organization. Laysan albatrosses are not nearly as graceful on land as they are in the air; even they seem surprised by the size of their feet. This may include same-sex sexual activity , courtship , affection , pair bonding , and parenting among same-sex animal pairs. Journal of Consulting and Clinical Psychology.
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Researchers speculate that young male bottlenose dolphins mount one another simply to establish trust and form bonds — but those bonds actually turn out to be critical to reproduction, since when males mature, they work in groups to cooperatively gain access to females. These ideas generally aim to explain only particular behaviors in a particular species.
So do journalists, he added — all people, really. My take on it is that homosexual behavior is not a uniform phenomenon. The point of heterosexual sex, Vasey said, no matter what kind of animal is doing it, is primarily reproduction. Even what the same-sex animals are doing varies tremendously from species to species.
When I visited Zuk at her lab at the University of California at Riverside last December, an online video clip of an octopus carrying a coconut shell around the seafloor, and periodically hiding under it, was starting to go viral. For a few days, people everywhere were flipping out about how intelligent and wily this octopus was.
Not Zuk, though. Nor is it doing something so uncommon in the animal world. Zuk explained that caddis-fly larvae collect rocks and loom them together into intricate shelters. Something similar may be happening with what we perceive to be homosexual sex in an array of animal species: we may be grouping together a big grab bag of behaviors based on only a superficial similarity.
Within the logic of each species, or group of species, many of these behaviors appear to have their own causes and consequences — their own evolutionary meanings, so to speak.
For the last 15 years, for example, Paul Vasey has been studying Japanese macaques, a species of two-and-a-half-foot-tall, pink-faced monkey. He has looked almost exclusively at why female macaques mount one another during the mating season.
Female macaques regularly mount males too, Vasey explained, probably to focus their attention and reinforce their bond as mates. The females are physically capable of mounting any gender of macaque. Laysan albatrosses are not nearly as graceful on land as they are in the air; even they seem surprised by the size of their feet. Later that week, at a nearby resort, I would recognize their gait while watching an out-of-shape snorkeler toddle back to his beach towel in rented flippers.
This is the luxury of studying Laysan albatrosses. Having evolved with no natural predators, the birds have no fight-or-flight instinct — you can basically go right up to one and grab it. In fact, Young did just this a short while later, slinking up to a male on all fours, sweeping it in by its flank and, in one expert motion, straightjacketing the wings under one arm and clamping the beak shut in her other hand.
Young and Marlene Zuk are now applying for a year National Science Foundation grant to continue studying the female albatross pairs. One of the first questions they want to answer is how these birds are winding up with fertilized eggs.
She was staking out Kaena Point on a daily basis, trying to watch these illicit copulations unfold for herself.
Young and I ambled around for half an hour, maybe more. They sat under a spindly, native Hawaiian naio bush. They made baa sounds at each other. After a while, Young and I got up. Another hour passed. Usually, Young brings along a camping chair. Occasionally, albatrosses danced in groups of two or three, raising their necks, groaning like vibrating cellphones, clacking their beaks or stomping. Homosexual activity is often observed in animal populations with a shortage of one sex — in the wild but more frequently at zoos.
Quickly mating with an otherwise-committed male, then pairing with another single female to incubate the egg, is a way to raise those odds. Still, pairing off with another female creates its own problems: nearly every female lays an egg in November whether she has managed to get it fertilized or not, and the small, craterlike nests that albatross pairs build in the dirt can accommodate only one egg and one bird. So Young was also trying to figure out how a female-female pair decides which of its two eggs to incubate and which to chuck out of the nest — if the birds are deciding at all, and not just knocking one egg out accidentally.
And these were only preambles to more questions. Ultimately, either the rules of albatrossdom were breaking down and the lesbian couples were booting up some alternate suite of behaviors, governed by its own set of rules, or else science had never thoroughly understood the rules of albatrossdom to begin with. Many people who contacted Young after the publication of her first albatross paper assumed she was a lesbian.
She is not. Young found the assumption offensive — not because she was being mistaken for gay, but because she was being mistaken for a bad scientist; these people seemed to presume that her research was compromised by a personal agenda. Still, some of the biologists doing the most incisive work on animal homosexuality are in fact gay.
View all New York Times newsletters. Only a few months before I visited Kaena Point, two penguins at the San Francisco Zoo became the latest in a tradition of captive same-sex penguin couples making global headlines. After six years together — in which the two birds even fostered a son, named Chuck Norris — the penguins split up when one of the males ran off with a female named Linda.
On the other hand, an Australian drag queen known as Dr. The book has also been cited in a brief filed for the Supreme Court case that overturned a Texas state ban on sodomy and, similarly, in a legislative debate on the floor of the British Parliament. James Esseks, director of the Lesbian, Gay, Bisexual and Transgender Project at the American Civil Liberties Union , told me he has never incorporated facts about animal behavior into a legal argument about the rights of human beings.
This is normal. This is part of the normal spectrum of humanity — or life. But later in our conversation, Esseks paused and stayed silent for a while. He was thinking like a lawyer again now, and found a hole in that line of reasoning. How could we, as humans, ever know? One e-mail message compared him with Dr. Still, many people who contacted Featherstone were actually grateful — for the same, baseless prospect.
There were poignant phone calls from parents, concerned about their gay children. It was hard not to be moved, and he would try to explain the implications of his research, or lack thereof, politely. Let your son be your son. Not long ago, more than two years after the publication of the fruit-fly paper, a woman wrote to Featherstone about her college-aged daughter. She was now contemplating suicide. The mother begged Featherstone to rethink his unwillingness to turn his fruit-fly research into a treatment.
Since , in addition to his investigation of female-female macaque sex, Vasey has also been studying a particular group of men in Samoa. In a paper published earlier this year, Vasey and one of his graduate students at the University of Lethbridge, Doug P. They are a kind of superuncle. Those family members will, after all, share a lot of the same genes. I was more likely to put the two hypotheses together because I was just more sensitive, I guess, to the reality that the world.
Humans are just another species. But unlike many biologists I spoke to, Vasey still seemed at ease discussing the speculative and even philosophical ties between animal and human sexuality.
They were right below her, 10 yards away on a flat, vegetated ridge. It was late afternoon. One albatross lay on its stomach, wobbling with its wings pulled back — the way penguins slide over ice — while a second stood upright behind it, fat rippling down its telescoping neck, as it pumped its pelvis.
The birds carried on for a while. Then the male shivered and retracted. The female came to her feet and walked off. The bird was part of a female-female pair. The male had another mate. Young started scribbling notes, and we sat there rapidly rehashing the details. One study observed four different gangs of males forcing themselves on a single female, which lost an eye in the process. But these two birds hardly seemed in a rush. Young made more notes.
Leonard — tall, lanky and tan, with a ponytail and a few days of scruff — is an ornithologist but works a desk job now for a state wildlife agency and seemed to be enjoying a morning outside. Eventually, Young spotted a female from one of the female-female pairs calling to a male about 15 feet away.
The female was standing right where the male and his partner usually build their nest. Her head was straight up in the air, and she clapped her beak animatedly. We sat on the ground expectantly for a while. Eventually, the male albatross took a few steps toward the calling female.
Living in highly social colonies, bonobos are more good-natured compared to their frequently violent chimpanzee relatives. Since many of the conflicts occur between two males or between two females, homosexual bonding is a frequent occurrence among these amorous apes. Bonobos are critically endangered, and they require the utmost effort from conservationists to keep them in the wild. Natural selection has led to some rather outlandish feather adornments. Remarkably, up to forty percent of males engage in same sex activity.
Unlike the seabirds previously discussed, only the male birds of this species seek homosexual encounters. It is possible that the gay behavior stems from high population densities, and extensive competition for females. African lions are frequently invoked as symbols of traditional rulership, especially in patriarchal societies which involve female harems.
A certain percentage of male African lions, however, forsake the available females in order to form their own same-sex group gatherings. Male lions have been documented mounting other males, and engaging in a variety of behaviors normally reserved for single pairs of opposite-sex couples. Though many other animal societies are structured in a way that might occasionally favor same-gender pairing, the reason for male lion associations is unknown. Lions have some of the strongest sex drives of any cat species, meaning that the encounters are probably more.
Homosexual behavior has been documented in wild Australian black swans, which sometimes form threesomes involving two males as they establish a nest site. Incredibly, such arrangements involving two males actually led to higher breeding success, due to the effectiveness of the males in defending the nest site from predators. Additionally, two male penguins made headlines after they paired up in a zoo, and were given an egg which they successfully raised.
Prior to being given an egg of their own, the gay penguins attempted to steal eggs from straight penguin couples. Ornithologists exploring the phenomenon have observed that, generally speaking, male bird pairs form among the more promiscuous songbird species, while female pairs form among monogamous species.
While such behavior was naturally established in some bird species, scientific research has indicated that increased rates of same sex pairing among the South American ibis may be the result of mercury pollution from mining operations, which changes sex hormones. Convergent evolution has given them a resemblance to the huge albatrosses, along with a similar mating system—again sometimes involving two females.
The more expressive gull pairs may even engage in mounting behaviors. This diversity in the colonies was first noticed when some nests were found to contain surprisingly large numbers of eggs. Young male giraffes , prior to mating with a female, sometimes engage in same-sex encounters and short term alliances.
Scientists theorize that the purpose of the same-gender interactions is to develop a familiarity with the mating techniques before using them to court the appropriate female giraffe.
Scientists explore the evolution of animal homosexuality
All rights reserved. Porter, who first hit it big in the s, wouldn't risk parading his homosexuality in public. In his day "the birds and the bees" generally meant only one thing—sex between a male and female.
But, actually, some same-sex birds do do it. So do beetles, sheep, fruit bats, dolphins , and orangutans. Zoologists are discovering that homosexual and bisexual activity is not unknown within the animal kingdom. They display classic pair-bonding behavior—entwining of necks, mutual preening, flipper flapping, and the rest. They also have sex, while ignoring potential female mates.
Wild birds exhibit similar behavior. There are male ostriches that only court their own gender, and pairs of male flamingos that mate, build nests, and even raise foster chicks. Filmmakers recently went in search of homosexual wild animals as part of a National Geographic Ultimate Explorer documentary about the female's role in the mating game. The film, Girl Power, will be screened in the U. S this Saturday at 8 p. ET, 5 p. The team caught female Japanese macaques engaged in intimate acts which, if observed in humans, would be in the X-rated category.
She argues that female macaques may enhance their social position through homosexual intimacy which in turn influences breeding success. Parish says, "Taking something that's nonreproductive, like mounting another female—if it leads to control of a resource or acquisition of a resource or a good alliance partner, that could directly impact your reproductive success.
On the other hand, they could just be enjoying themselves, suggests Paul Vasey, animal behavior professor at the University of Lethbridge, Alberta, Canada. It doesn't have any sort of adaptive payoff. Matthew Grober, biology professor at Georgia State University, agrees, saying, "If [sex] wasn't fun, we wouldn't have any kids around.
So I think that maybe Japanese macaques have taken the fun aspect of sex and really run with it. The bonobo, an African ape closely related to humans, has an even bigger sexual appetite.
Studies suggest 75 percent of bonobo sex is nonreproductive and that nearly all bonobos are bisexual. Frans de Waal, author of Bonobo: The Forgotten Ape, calls the species a "make love, not war" primate.
He believes bonobos use sex to resolve conflicts between individuals. Other animals appear to go through a homosexual phase before they become fully mature. For instance, male dolphin calves often form temporary sexual partnerships, which scientists believe help to establish lifelong bonds. Such sexual behavior has been documented only relatively recently.
Zoologists have been accused of skirting round the subject for fear of stepping into a political minefield. Whether it's a good idea or not, it's hard not make comparisons between humans and other animals, especially primates.
The fact that homosexuality does, after all, exist in the natural world is bound to be used against people who insist such behavior is unnatural.
In the U. Many on the religious right regard homosexuality as a sin. And only this month, President Bush vowed to continue his bid to ban gay marriages after the Senate blocked the proposal. Already, cases of animal homosexuality have been cited in successful court cases brought against states like Texas, where gay sex was, until recently, illegal. Yet scientists say we should be wary of referring to animals when considering what's acceptable in human society. For instance, infanticide, as practiced by lions and many other animals, isn't something people, gay or straight, generally approve of in humans.
So how far can we go in using animals to help us understand human homosexuality? Robin Dunbar is a professor of evolutionary psychology at the University of Liverpool, England. Dunbar says the bonobo's use of homosexual activity for social bonding is a possible example, adding, "One of the main arguments for human homosexual behavior is that it helps bond male groups together, particularly where a group of individuals are dependent on each other, as they might be in hunting or warfare.
For instance, the Spartans, in ancient Greece, encouraged homosexuality among their elite troops. Another suggestion is that homosexuality is a developmental phase people go through. He said, "This is similar to the argument of play in young animals to get their brain and muscles to work effectively and together.
Off the back of this, there's the possibility you can get individuals locked into this phase for the rest of their lives as a result of the social environment they grow up in.
But he adds that homosexuality doesn't necessarily have to have a function. It could be a spin-off or by-product of something else and in itself carries no evolutionary weight.
He cites sexual gratification, which encourages procreation, as an example. In other words, if the urge to have sex is strong enough it may spill over into nonreproductive sex, as suggested by the actions of the bonobos and macaques.
However, as Dunbar admits, there's a long way to go before the causes of homosexuality in humans are fully understood. He said, "Nobody's really investigated this issue thoroughly, because it's so politically sensitive.
It's fair to say all possibilities are still open. So go the lyrics penned by U. By James Owen. Well, perhaps, in a roundabout way, they are seeking males, suggests primatologist Amy Parish. Continue Reading.