Sunday, July 13, 2008
The Phoenix Mars lander suffered a short circuit several weeks ago to one of its eight tiny test ovens. Scientists fear another outage could render the crucial equipment useless.
So they've speeded up their mission, skipping plans for a slow, deliberate set of heating experiments and moving ahead for the dramatic conclusion.
The change in game plan is the biggest challenge yet for a mission that got off to an impressive start.
Phoenix survived a 10-month journey through space and nailed a perfect touchdown on May 25 on the polar plains. It has wowed scientists by touching ice and finding Earth-like soil.
But it's a complicated, odd contraption. The lander's equipment includes the eight miniature ovens, two microscopes and a chemistry lab to conduct experiments. It also has a long arm for digging trenches. Plans called for it to take several scoops of Martian dirt and ice at different depths over a period of weeks. Each sample was to be baked in one of the ovens, with tests run on the vapors produced to check for the carbon compounds essential to life.
Scientists wanted to understand how the soil chemistry changed according to depth, an analysis that would help them when they test the Martian ice.
"We really feel we need a slow deliberate process to make sure that when we go for the pay dirt - that icy soil down at the bottom of the trench - that we're fully prepared to do it properly," chief scientist Peter Smith of the University of Arizona in Tucson said last month after confirming the presence of ice at the landing site.
Last week, Smith said in a statement: "We are taking the most conservative approach and treating the next sample to (the oven) as possibly our last."
After the outage that zapped an oven, the science team decided to skip several steps. In recent days, they've been working toward their big ice dig.
This effort too is encountering snags.
Earlier this week, Phoenix used the blade at the end of its robotic arm scoop to chip at the hard ice. None of the ice bits made it into the scoop, forcing scientists to break out a power tool to drill into the ice. The next oven test could happen as early as next week.
Researchers who have no role in the three-month project said they would be saddened if the oven became disabled since it's the only instrument that can detect carbon.
Planetary scientist David Paige of the University of California, Los Angeles, said it makes sense for mission scientists to go after the ice. But he worried that studying frozen water without a full knowledge of the soil could make it difficult to interpret the results.
"It's a tough predicament," said Paige, who is not part of the mission. "The fact that they managed to land in such a promising locale makes the potential loss all that more difficult."
NASA's checklist for "full mission success" requires Phoenix to analyze at least three oven samples. So far, the lander has completed only one - enough to achieve "minimum mission success" last weekend, said project manager Barry Goldstein of NASA's Jet Propulsion Laboratory in Pasadena.
Results from the first heating of soil detected water vapor and carbon dioxide, but no signs of carbon.
It was that first oven test that led to the problematic electrical short. The scoop dumped so much soil that it clogged a mesh screen filter over the oven. To break up the dirt, technicians shook the instrument for several days.
Engineers think the shaking caused the short circuit, and an independent engineering group reported that the problem could happen again if an oven is turned on.
Goldstein of JPL said he doesn't expect future problems, but the team did not want to chance it.
"It's not that we expect one to occur," said Goldstein of another possible short. "It's just us being very cautious."
© 2008 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
Whenever I lose my watch, I take my sweet time to get a new one. I savor the freedom from my compulsion to carve my days into minute-size fragments. But my liberty has its limits. Even if I get rid of the clock strapped to my wrist, I cannot escape the one in my head. The human brain keeps time, from the flicker of milliseconds to the languorous unfurling of hours and days and years. It’s the product of hundreds of millions of years of evolution.
Keeping track of time is essential for perceiving what’s happening around us and responding to it. In order to tell where a voice is coming from, we time how long it takes for the sound to reach both ears. And when we respond to the voice by speaking ourselves, we need precise timing to make ourselves understood. Our muscles in the mouth, tongue, and throat must all twitch in carefully timed choreography. It’s just a brief pause that makes the difference between “Excuse me while I kiss the sky” and “Excuse me while I kiss this guy.”
Scientists are finding that telling time is also important to animals. At the University of Edinburgh, researchers built fake flowers with sugar inside to reveal how hummingbirds tell time. After hummingbirds drink nectar from real flowers, it takes time for the flowers to replenish their supply. The Scottish researchers refilled some of their fake flowers every 10 minutes and others every 20. Hummingbirds quickly learned just how long they had to wait before coming back to each kind. Scientists at the University of Georgia have discovered that rats do an excellent job of telling time too. They can be conditioned to wait two days after a meal to poke their noses into a trough and be rewarded with food.
For 40 years, psychologists thought that humans and animals kept time with a biological version of a stopwatch. Somewhere in the brain, a regular series of pulses was being generated. When the brain needed to time some event, a gate opened and the pulses moved into some kind of counting device.
One reason this clock model was so compelling: Psychologists could use it to explain how our perception of time changes. Think about how your feeling of time slows down as you see a car crash on the road ahead, how it speeds up when you’re wheeling around a dance floor in love. Psychologists argued that these experiences tweaked the pulse generator, speeding up the flow of pulses or slowing it down.
Staring at an angry face for five seconds feels longer than staring at a neutral one.
But the fact is that the biology of the brain just doesn’t work like the clocks we’re familiar with. Neurons can do a good job of producing a steady series of pulses. They don’t have what it takes to count pulses accurately for seconds or minutes or more. The mistakes we make in telling time also raise doubts about the clock models. If our brains really did work that way, we ought to do a better job of estimating long periods of time than short ones. Any individual pulse from the hypothetical clock would be a little bit slow or fast. Over a short time, the brain would accumulate just a few pulses, and so the error could be significant. The many pulses that pile up over long stretches of time should cancel their errors out. Unfortunately, that’s not the case. As we estimate longer stretches of time, the range of errors gets bigger as well.
These days, new kinds of experiments using everything from computer simulations to brain scans to genetically engineered mice are helping unlock the nature of mental time. And their results show that the brain does not use a single stopwatch. Instead, it has several ways to tell time, and none of them seems to work like a conventional clock.
Dean Buonomano, a neuroscientist at UCLA, argues that in order to perceive time in fractions of a second, our brains tell time as if they were observing ripples on a pond. Let’s say you are listening to a chirping bird. Two of its chirps are separated by a tenth of a second. The first chirp triggers a spike of voltage in some auditory neurons, which in turn causes some other neurons to fire as well. The signals reverberate among the neurons for about half a second, just as it takes time for the ripples from a rock thrown into a pond to disappear. When the second chirp comes, the neurons have not yet settled down. As a result, the second chirp creates a different pattern of signals. Buonomano argues that our brains can compare the second pattern to the first to tell how much time has passed. The brain needs no clock because time is encoded in the way neurons behave.
If Buonomano turns out to be right, he will have explained only our fastest time telling, because after half a second, the brain’s ripples dissipate. On the scale of seconds to hours, the brain must use some other strategy. Warren Meck of Duke University argues that the brain measures long stretches of time by producing pulses. But the brain does not then count the pulses in the way a clock does. Instead, Meck suspects, it does something more elegant. It listens to the pulses as if they were music.
It’s possible that we reverse time in our memories in order to focus our brains on goals.
Meck first began to develop his musical model when he discovered how to rob rats of their perception of time. He had only to destroy certain clumps of neurons deep inside the brain. Some of these neurons, known as medium spiny neurons, are unlike any other neurons in the brain. Each one is linked to as many as 30,000 other neurons. And those linked neurons can be found throughout the cortex, the outer rind of the brain that handles much of the brain’s most sophisticated information processing. Certain neurons come from regions that handle vision, others from areas that apply rules to what we perceive, and so on. By receiving so many signals from all over the brain, Meck believes, the medium spiny neurons give us a sense of time.
Imagine you are listening to a 10-second tone. At the beginning of the tone, neurons around your cortex reset themselves, so that they all begin to fire in sync. But some fire faster than others, and so at any moment some are active and some are quiet. From one moment to the next, a medium spiny neuron receives a unique pattern of signals from the neurons that link to it. The pattern changes like chords on a piano. When the 10 seconds are over, the medium spiny neuron can simply “listen” to the chord to tell how much time has passed.
Meck has found support for his model by recording the electrical activities of neurons and in other researchers’ studies on people with a skewed sense of time. Certain neurotransmitters, such as dopamine, control pulsing neurons. Drugs such as cocaine and methamphetamine alter the brain by flooding it with dopamine, and studies have shown that they also change the second-to-second perception of time. In one experiment at UCLA, reported in 2007, scientists rang a bell after 53 seconds of silence. Healthy people estimated on average that 67 seconds had passed. Stimulant addicts guessed 91 seconds. Other drugs have the opposite effect on dopamine and compress the subjective experience of time.
IN REAL TIME
Even in a healthy brain, time is elastic. Staring at an angry face for five seconds feels longer than staring at a neutral one. It may be no coincidence that the pulse-generating neurons are directly wired into regions of the brain that handle emotionally charged sights and sounds. And recent experiments by Amelia Hunt at Harvard University hint that we may actually backdate our mental time line every time we move our eyes.
Recently, Hunt had people stare straight ahead with a ticking clock off to one side. She asked people to move their eyes over to the clock and make a note of the time when they had done so. On average, they reported seeing the clock about four hundredths of a second before their eyes actually arrived there.
Moving time backward may actually serve us well, by letting us cope with an imperfect nervous system. Each of our retinas has a small patch of densely packed, light-sensitive cells called the fovea. In order to get a detailed picture of our surroundings, we have to jerk our eyes around several times a second so that the fovea can scan them. On its own, this stream of signals from our eyes would produce a jarring series of jump cuts. Our brains manufacture the illusion of a seamless flow of reality. In the course of that editing, we may need to fudge the time line—both in anticipation of an event and after the fact.
But the most radical reworking of time may come as we inscribe it in our memories. We recall not just what happened but when. We can recall how much time has passed since an event occurred by tapping into our memories. Injuries and surgeries that destroy a particular part of the brain can give some hints about how the brain records time in memory. French scientists in 2007 reported their study of a group of patients who had suffered damage to a region known as the left temporal lobe. The patients watched a documentary, and a familiar object appeared on the screen, then reappeared a few minutes later. The patients had to guess how much time had passed. On average, the patients thought an 8-minute period was roughly 13. (Normal subjects were off by only about a minute.)
These experiments are helping scientists zero in on the regions of the brain that store memories of time. Exactly how those regions record time is still mysterious. It’s one thing to listen in on the brain’s music, recognizing chords that mark the passage of five minutes. But how do the brain’s memory-related neurons then archive those five minutes so that they can be recalled later?
At Humboldt University of Berlin in Germany, scientists have been building a model of how memory may store time. When neurons produce a regular cycle of signals, some signals come a little sooner and some come a little later. The researchers propose that as neurons pass these signals along, they can add tiny advances, some bigger than others. With these tiny wobbles, the brain can compress memories of time from several seconds down to hundredths of a second—a small enough package to store for later retrieval.
As it stores time in memories, the brain may alter it in another way that is even more radical. It may record time so that our brains recall events in backward order. Scientists at MIT discovered reverse memories in an experiment on rats. They had rats run down a track and then stop to eat food at the end. When rats (and humans) become more familiar with a place, individual neurons start becoming active when the rats reach particular spots. The scientists identified “place cells” that fired when the rats moved to different spots along the track. When the rats stopped to eat, the scientists eavesdropped on their brains again. They heard the place neurons fire again—probably as the memories of the track were becoming stronger in the rat brain. But the place neurons at the end of the track fired first, and the ones at the beginning of the track fired last. It’s possible that we reverse time in our memories in order to focus our brains on goals (for the MIT rats, the goal was the food at the end of the track).
We are not free from time, in other words, but we are not its slaves. We stretch and twist it to serve our own needs. Time, in other words, is just a tool.
The key step, which is carried out continuously in plants, is the breakdown, using light, of water into its Hydrogen and Oxygen components: This has long been a goal of chemists, but has so far eluded them.
In layman's terms, the problem is energy: Visible light "can only contribute a limited amount of energy towards a chemical reaction. This energy is absorbed by electrons involved in the reaction." Photosnthesis requires that several electrons involved in the reaction are energised, and is referred to as a "multiple electron system".
The challenge has been to recreate these multiple electron systems in the lab, but so far no one has succeeded in creating one with sufficient energy to power photosynthesis.
The promise of Carbon nanotubes, is that their structure is such that for each 32 carbon atoms in its fabric, it can 'accept' (i.e. absorb) a single electron: this means that even a tiny nanotube could potentially absorb millions of electrons at a time, and could potentially act as a 'receiver molecule' for artificial photosynthesis.
Artificial photosynthesis promises an efficient way of producing Hydrogen, which could potentially provide a clean fuel for vehicles: all that would be needed is water. Although a long way off, this breakthrough satisfies a vital requirement of any future models.
Sounding like something Arthur C Clarke might have come up with if he had scripted Saturday Night Fever, a London club launches tonight that claims it will be powered by clubbers shaking their stuff on its dance floor.
Named Surya, the King's Cross nightclub is billing itself as the world's first eco-disco. It is the baby of Dr Earth aka property developer Andrew Charalambous. Worth an estimated £100 million, Charalambous, who in the past stood as a Conservative parliamentary candidate, has invested £1 million in the project and claims the aim of the venture “is to go beyond the concept of sustainability and into the realm of ecology, generating surplus energy to power not only the club but also neighbouring properties.”
Made of materials such as quartz crystals and ceramics, the venue’s dance floor, they claim, uses the concept of piezoelectricity in which the materials rub together to create a charge. Normally used in electric cigarette lighters, this will be the first project of its kind using the technology. Recently a US-based project attempted and failed to power battlefield equipment by generators embedded in soldiers' boots.
Other more conventional initiatives at the site include a wind turbine, solar energy system, waterless urinals, low flush toilets, recycling and, somewhat paradoxically, ‘the latest in ecological air conditioning units'.
All guests will be required to sign a pledge to work towards curbing climate change and tonight, in his Dr Earth guise, Charalambous will be unveiling a “10 point manifesto for all club owners and promoters across the world to adopt and do their bit, however small, towards saving the planet.”
Hosting the glitzy launch party will be luxury jeweller and DJ Jade Jagger. Mayor of London Boris Johnson and Conservative leader David Cameron are also rumoured to be attending. No doubt the cha cha cha skills they demonstrated the night of Boris's Mayoral win will create enough wattage for Jagger to at least spin Duran Duran's apocalypto-pop anthem, Planet Earth.
Watch the orginal Planet Earth - purely for fun
Surya is at 156 Pentonville Road London N1 9JL
Considering that cow flatulence makes up over 30% of
Anyway, the backpacks don’t seem to bother the cows much, and we’ll have to wait and see the results of these odd tests – and wait to see if someone figures out how to run cars on the methane collected from feedlots…and, um, other sources. Personally, I say we all just eat less red meat and skip manufacturing yet more plastic or wasting time on selective breeding.However, I love the fact that cattle emissions is getting the attention it needs, and I won’t bash on this backpack much – and I won’t even get started on the long list of issues to using this on a large scale – because it’s likely not going to be a realistic solution to global warming anyway.
Typically, corals reproduce by releasing sperm and egg cells into the water. They do this at the same time, in a process called synchronous spawning, to maximize their chances of success. Basically, the more sperm and egg cells that are in the water at the same time, the higher the rate of fertilization.
With this in mind, corals have developed a keen sense of timing. Often, all of the coral in a reef will release their reproductive cells on the same day. Scientists do not know exactly how corals manage to time this so perfectly, but they believe it may involve water temperature, sunlight and moonlight.
Researchers now believe that climate change may be disrupting this process, and causing corals to release their sex cells at different times. This greatly reduces their chances of reproductive success.
Corals routinely face dangers from fishing, boating, tourism and other human activity. In light of this new research, we need to strengthen our efforts to protect coral reefs. They are a true treaure of this planet, and provide a habitat for a great number of amazing and unique species.
The system will pump cool water, about 45° F, from 1,600 feet below the ocean waves. The water will travel through the pump system to an onshore station where it will cool fresh water that circulates in a closed loop through customers’ buildings in downtown
I’m also curious as to what fuel is going to be used to power the system. Hopefully they’ll take a hint from the newly required solar-powered water heaters and go renewable with the system. Regardless, the savings potential is astounding.
Two penguins native to Antarctica met one spring day in 1998 in a tank at the Central Park Zoo in midtown Manhattan. They perched atop stones and took turns diving in and out of the clear water below. They entwined necks, called to each other and mated. They then built a nest together to prepare for an egg. But no egg was forthcoming: Roy and Silo were both male.
Robert Gramzay, a keeper at the zoo, watched the chinstrap penguin pair roll a rock into their nest and sit on it, according to newspaper reports. Gramzay found an egg from another pair of penguins that was having difficulty hatching it and slipped it into Roy and Silo’s nest. Roy and Silo took turns warming the egg with their blubbery underbellies until, after 34 days, a female chick pecked her way into the world. Roy and Silo kept the gray, fuzzy chick warm and regurgitated food into her tiny black beak.
Like most animal species, penguins tend to pair with the opposite sex, for the obvious reason. But researchers are finding that same-sex couplings are surprisingly widespread in the animal kingdom. Roy and Silo belong to one of as many as 1,500 species of wild and captive animals that have been observed engaging in homosexual activity. Researchers have seen such same-sex goings-on in both male and female, old and young, and social and solitary creatures and on branches of the evolutionary tree ranging from insects to mammals.
Unlike most humans, however, individual animals generally cannot be classified as gay or straight: an animal that engages in a same-sex flirtation or partnership does not necessarily shun heterosexual encounters. Rather many species seem to have ingrained homosexual tendencies that are a regular part of their society. That is, there are probably no strictly gay critters, just bisexual ones. “Animals don’t do sexual identity. They just do sex,” says sociologist Eric Anderson of the University of Bath in England.
Nevertheless, the study of homosexual activity in diverse species may elucidate the evolutionary origins of such behavior. Researchers are now revealing, for example, that animals may engage in same-sex couplings to diffuse social tensions, to better protect their young or to maintain fecundity when opposite-sex partners are unavailable—or simply because it is fun. These observations suggest to some that bisexuality is a natural state among animals, perhaps Homo sapiens included, despite the sexual-orientation boundaries most people take for granted. “[In humans] the categories of gay and straight are socially constructed,” Anderson says.
What is more, homosexuality among some species, including penguins, appears to be far more common in captivity than in the wild. Captivity, scientists say, may bring out gay behaviors in part because of a scarcity of opposite-sex mates. In addition, an enclosed environment boosts an animal’s stress levels, leading to a greater urge to relieve the stress. Some of the same influences may encourage what some researchers call “situational homosexuality” in humans in same-sex settings such as prisons or sports teams.
Modern studies of animal homosexuality date to the late 19th century with observations on insects and small animals. In 1896, for example, French entomologist Henri Gadeau de Kerville of the Society of Friends of Natural Sciences and the Museum of Rouen published a drawing of two male scarab beetles copulating. Then, during the first half of the 1900s, various investigators described homosexual behavior in baboons, garter snakes and gentoo penguins, among other species. Back then, scientists generally considered homosexual acts among animals to be abnormal. In some cases, they “treated” the animals by, say, castrating them or giving them lobotomies.
At least one early report, however, was more than descriptive, yielding insight into the possible origins of the behavior. In a 1914 lab experiment Gilbert Van Tassel Hamilton, a psychopathologist practicing in Montecito, Calif., reported that same-sex behavior in 20 Japanese macaques and two baboons occurred largely as a way of making peace with would-be foes. In the Journal of Animal Behavior Hamilton observed that females offered sex to the more dominant macaques of the same sex: “homosexual behavior is of relatively frequent occurrence in the female when she is threatened by another female, but it is rarely manifested in response to sexual hunger.” And in males, he penned, “homosexual alliances between mature and immature males may possess a defensive value for immature males, since they insure the assistance of an adult defender in the event of an attack.”
More recently, some researchers studying bonobos (close relatives of the chimpanzee) have come to similar conclusions. Bonobos are highly promiscuous, and about half their sexual activity involves same-sex partners. Female bonobos rub one another’s genitals so often that some scientists have suggested that their genitalia evolved to facilitate this activity. The female bonobo’s clitoris is “frontally placed, perhaps because selection favored a position maximizing stimulation during the genital-genital rubbing common among females,” wrote behavioral ecologist Marlene Zuk of the University of California, Riverside, in her 2002 book Sexual Selections: What We Can and Can’t Learn about Sex from Animals. Male bonobos have been observed to mount, fondle and even perform oral sex on one another.
Such behavior seems to ease social tensions. In Bonobo: The Forgotten Ape (University of California Press, 1997), Emory University primatologist Frans B. M. de Waal and his co-author photographer Frans Lanting wrote that “when one female has hit a juvenile and the juvenile’s mother has come to its defense, the problem may be resolved by intense GG-rubbing between the two adults.” De Waal has observed hundreds of such incidents, suggesting that these homosexual acts may be a general peacekeeping strategy. “The more homosexuality, the more peaceful the species,” asserts Petter Böckman, an academic adviser at the University of Oslo’s Museum of Natural History in Norway. “Bonobos are peaceful.”
In fact, such acts are so essential to bonobo socialization that they constitute a rite of passage for young females into adulthood. Bonobos live together in groups of about 60 in a matriarchal system. Females leave the group during adolescence and gain admission to another bonobo clan through grooming and sexual encounters with other females. These behaviors promote bonding and give the new recruits benefits such as protection and access to food.
In some birds, same-sex unions, particularly between males, might have evolved as a parenting strategy to increase the survival of their young. “In black swans, if two males find each other and make a nest, they’ll be very successful at nest making because they are bigger and stronger than a male and female,” Böckman says. In such cases, he says, “having a same-sex partner will actually pay off as a sensible life strategy.”
In other instances, homosexual bonding between female parents can boost the survival of offspring when male-female pairings are not possible. In birds called oystercatchers, intense competition for male mates would leave some females single were it not for polygamous trios. In a study published in 1998 in Nature, zoologist Dik Heg and geneticist Rob van Treuren, both then at the University of Groningen in the Netherlands, observed that roughly 2 percent of oystercatcher breeding groups consist of two females and a male. In some of these families, Heg and van Treuren found, the females tend separate nests and fight over the male, but in others, all three birds watch over a single nest. In the latter case, the females bond by mounting each other as well as the male. The cooperative triangles produce more offspring than the competitive ones, because such nests are better tended and protected from predators.
Such arrangements point to the evolutionary fitness of stable social relationships, whatever their type. Biologist Joan E. Roughgarden of Stanford University believes that evolutionary biologists tend to adhere too strongly to Darwin’s theory of sexual selection and have thus largely overlooked the importance of bonding and friendship to animal societies and the survival of their young.“ [Darwin] equated reproduction with finding a mate rather than paying attention to how the offspring are naturally reared,” Roughgarden says.
Protection of progeny, social bonding and conflict avoidance may not be the only reasons animals naturally come to same-sex relationships. Many animals do it simply “because they want to,” Böckman says. “People view animals as robots who behave as their genes say, but animals have feelings, and they react to those feelings.” He adds that “as long as they feel the urge [for sex], they’ll go for it.”
A recent finding indicates that homosexual behavior may be so common because it is rooted in an animal’s brain wiring—at least in the case of fruit flies. In a study appearing earlier this year in Nature Neuroscience, neuroscientist David E. Featherstone of the University of Illinois at Chicago and his colleagues found that they could switch on homosexual leanings in fruit flies by manipulating a gene for a protein they call “genderblind,” which regulates communication between neurons that secrete and respond to the neurotransmitter glutamate.
Males that carried the mutant genderblind gene—which depressed levels of the protein by about two thirds—were uncharacteristically attracted to the chemical cues exuded by other males. As a result, these mutant males courted and attempted to copulate with other males. The finding suggests that wild fruit flies may be prewired for both heterosexual and homosexual behavior, the authors write, but that the genderblind protein suppresses the glutamate-based circuits that promote homosexual behavior. Such brain architecture may enable same-sex behavior to surface easily, supporting the notion that it might confer an evolutionary advantage in some circumstances.
The Captivity Effect
In some less social species, homosexual behavior is almost unheard of in wild animals but may surface in captivity. Wild koalas, which are mostly solitary, seem to be strictly heterosexual. But in a 2007 study veterinary scientist Clive J. C. Phillips of the University of Queensland in Brisbane, Australia, and his colleagues observed 43 instances of homosexual activity among female koalas living in a same-sex enclosure at the Lone Pine Koala Sanctuary. The captive females shrieked male mating calls and mated with one another, sometimes participating in multiple encounters of up to five koalas. “The behavior in captivity was certainly enhanced in terms of homosexual activity,” Phillips says.
He believes that the females acted this way in part because of stress. Animals often experience stress in enclosed habitats and may engage in homosexual behavior to relieve that tension. A lack of male partners probably also played a role, Phillips suggests. When female koalas are in heat, their ovaries release the sex hormone estrogen, which triggers mating behavior—whether or not males are present. This hardwired urge to copulate, even if expressed with a female partner, might be adaptive. “The homosexual behavior preserves sexual function,” Phillips says, enabling an animal to maintain its reproductive fitness and interest in sexual activity. In males, this benefit is even more obvious: homosexual behavior stimulates the continued production of seminal fluid.
A lack of opposite-sex partners is also thought to help explain the prevalence of homosexuality among penguins in zoos. In addition to several gay penguin couplings in the U.S., 20 same-sex penguin partnerships were formed in 2004 in zoos in Japan. Such behavior “is very rare in penguins’ natural habitats,” says animal ecologist Keisuke Ueda of Rikkyo University in Tokyo. Thus, Ueda speculates that the behavior—which included both male pairings and female couplings—arose as a result of the skewed sex ratios at zoos.
Researchers have found still other reasons for homosexual behavior in domesticated cattle—which is such a common occurrence that farmers and animal breeders have developed terms for it. “Bulling” refers to male pairs mounting, and “going boaring” is its female counterpart. For cows, the behavior is not just a stress reliever. It is a way to signal sexual receptivity. The females mount one another to signal their readiness to mate to the bulls—which, in captivity, may cause a breeder to know when to bring in a suitable opposite-sex partner.
Homosexual mounting is much rarer among cattle in the wild, Phillips asserts, based on his research on gaurs in Malaysia, a wild counterpart to domesticated cattle. “Cattle evolved in the forest, so a visual signal was not going to be useful for them,” he says.
Stress and the greater availability of same-sex partners may similarly contribute to the practice of homosexual acts among self-described heterosexual humans in environments such as the military, jails and sports teams. In a study published this year in the journal Sex Roles, Anderson found that 40 percent of 49 heterosexual former high school football players attending various U.S. universities had had at least one homosexual encounter. These ranged from kissing to oral sex to threesomes that included a woman. In team sports, homosexuality is “no big deal and it increases cohesion among members of that team,” Anderson claims. “It feels good, and [the athletes] bond.”
In stressful same-sex environments such as prisons or a war zone, heterosexuals may engage in homosexual behavior in part to relieve tension. “Homosexuality appears mostly in social species,” Böckman says. “It makes flock life easier, and jail flock life is very difficult.”
In recent decades zoo officials have tried to minimize the stresses of captivity by making their enclosures more like animals’ natural habitats. In the 1950s zoo animals lived behind bars in barren enclosures. But since the late 1970s zoo homes have become more hospitable, including more open space, along with plants and murals representative of an animal’s natural habitat. The Association of Zoos and Aquariums (AZA) regulates everything from cage dimensions to animal bedding. The AZA also outlines enrichment activities for captive creatures: for instance, two golden brown Amur leopards at the Staten Island Zoo regularly play with a papier-mâché zebra, an animal they have never seen in the flesh.
Researchers hope such improvements might affect animal behavior, making it more like what occurs in the wild. One possible sign of more hospitable conditions might be a rate of homosexuality more in line with that of wild members of the same species. Some people, however, contest the notion that zookeepers should prevent or discourage homosexual behavior among the animals they care for.
And whereas captivity may engender what appears to be an unnaturally high level of homosexual activity in some animal species, human same-sex environments might bring out normal tendencies that other settings tend to suppress. That is, some experts argue that humans, like some other animals, are naturally bisexual. “We should be calling humans bisexual because this idea of exclusive homosexuality is not accurate of people,” Roughgarden says. “Homosexuality is mixed in with heterosexuality across cultures and history.”
Even Silo the penguin, who had been coupled with Roy for six years, displayed this malleability of sexual orientation. One spring day in 2004 a female chinstrap penguin named Scrappy—a transplant from SeaWorld in San Diego—caught his eye, and he abruptly left Roy for her. Meanwhile Roy and Silo’s “daughter,” Tango, carried on in the tradition of her fathers. Her chosen mate: a female named Tazuni.
This story was originally printed with the title, "Bisexual Species".
There's only so much you can do searching for extraterrestrial life when you're Earthbound. One approach is to locate and study the best terrestrial examples of what might resemble conditions that could support life on another planet.
View Slide Show Exploration of the Lake
That is exactly why astrobiologists are getting so excited about Pavilion Lake in British Columbia, Canada. Pavilion's lake floor is scattered with living coral reef–like structures called microbialites that result from microbes and minerals interacting over thousands of years. Although Pavilion's microbialites are believed to date back 11,000 years, they uncannily resemble structures that flourished on Earth some 540 million years ago.
Freshwater microbialites can be found in a handful of other places on Earth, but the diversity of structures at Pavilion is what sets it apart. There you will find microbialites shaped like cauliflower florets or artichokes growing on flat stretches of the lake's floor as well as ones that form chimneys and fingerlike protrusions, which cling to steep trenches farther down.
The idea is simple: If scientists can recognize what early life on Earth looks like, their hunt for life elsewhere should be better informed—because odds are that if life exists or existed, say, on Mars, it would be of the primitive sort. Along those lines, the research team at Pavilion has employed two single-person submersibles to map the lake floor this year. They are also busy sampling the lake's components (its sediment, water, isotopes and DNA from microbialites themselves) to reveal the signature of microbialite life. Once uncovered, tests could be devised to determine on future missions to Mars and other planets if similar structures are present.
When NASA astrobiologist Chris McKay emerged from Pavilion's waters after his first dive there he said: "I think I just walked back in time." Take the time trip yourself with this slide show.