The Best American Science and Nature Writing 2011

by Mary Roach

  Given this big umbrella of theory, the very existence of homosexual behavior in animals can feel a little like impenetrable nonsense, something a researcher could spend years banging his or her head against the wall deliberating. The difficulty of that challenge, more than any implicit or explicit homophobia, may be why past biologists skirted the subject.

  In the last decade, however, Paul Vasey and others have begun developing new hypotheses based on actual, prolonged observation of different animals, deciphering the ways given homosexual behaviors may have evolved and the evolutionary role they might play within the context of individual species. Different ideas are emerging about how these behaviors could fit within that traditional Darwinian framework, including seeing them as conferring reproductive advantages in roundabout ways. Male dung flies, for example, appear to mount other males to tire them out, knocking them out of competition for available females. 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 far, the only real conclusion this relatively small body of literature seems to point to, collectively, is a kind of deflating meta-conclusion: a single explanation of homosexual behavior in animals may not be possible, because thinking of "homosexual behavior in animals" as a single scientific subject might not make much sense. "Biologists want to build these unified theories to explain everything they see," Vasey told me. So do journalists, he added—all people, really. "But none of this lends itself to a linear story. My take on it is that homosexual behavior is not a uniform phenomenon. Having one unifying body of theory that explains why it's happening in all these different species might be a chimera."

  The point of heterosexual sex, Vasey said, no matter what kind of animal is doing it, is primarily reproduction. But that shouldn't trick us into thinking that homosexual behavior has some equivalent organizing purpose—that the two are tidy opposites. "All this homosexual behavior isn't tied together by that sort of primary function," Vasey said. Even what the same-sex animals are doing varies tremendously from species to species. But we're quick to conceive of that great range of activities in the way it most handily tracks to our anthropomorphic point of view: put crassly, all those different animals just seem to be doing gay sex stuff with one another. As the biologist Marlene Zuk explains, we are hard-wired to read all animal behavior as "some version of the way people do things" and animals as "blurred, imperfect copies of humans."

  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. "Oh, spare me," she said. To us, Zuk explained, that octopus's behavior reads as proof that "octopuses are at one with humans" because it just happens to look like something we do—how a toddler plays peekaboo under a blanket, say, or a bandit ducks into an alleyway dumpster to avoid the cops. But the octopus doesn't know that. 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. "But for some reason we don't think that's cool," she said, "because the caddis-fly larvae don't have big eyes like us."

  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. The Stanford biologist Joan Roughgarden told me to think of all these animals as "multitasking" with their private parts.

  It's also possible that some homosexual behaviors don't provide a conventional evolutionary advantage; but neither do they upend everything we know about biology. For the last fifteen 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. Vasey now says he is on to the answer: "It isn't functional," he told me; the behavior has no discernible purpose, adaptationally speaking. Instead, it's a byproduct of a behavior that does, and the supposedly streamlining force of evolution just never flushed that byproduct from the gene pool. 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. They've just never developed an instinct to limit themselves to one. "Evolution doesn't create perfect adaptations," Vasey said. As Zuk put it, "There's a lot of slop in the system—which," she was sure to add, "is not the same as saying homosexuality is a mistake."

  About two dozen birds were knocking around when Lindsay Young and I arrived at Kaena Point one afternoon. Young dished about a few of them—"Her mate didn't show up last year"; "God, this one's annoying"—as they waddled by. 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.) "I'm just writing down who's here," Young said, reading the numbers on the birds' leg bands and marking them on her clipboard. After trying and failing to get a clear view of one bird's leg with binoculars, she finally just walked to within a few feet of the animal and leaned over to look.

  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, straitjacketing the wings under one arm and clamping the beak shut in her other hand. Then she walked over and handed the thing to me; she needed to take an expensive tracking device off the bird's ankle. "Sorry, but it's like watching a thousand-dollar bill fly around," she said. She took some pliers from her backpack to twist off the anklet and, as I stood bear-hugging the albatross, she added: "They have a nice smell. It's a little musty."

  Young and Marlene Zuk are now applying for a ten-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. Typically, albatrosses fend off birds who aren't their mates. So Young has been trying to determine if males who arrive back at the colony before their own partners do are forcing themselves on these females or whether these females are somehow "soliciting" the males for sex. She was staking out Kaena Point on a daily basis, trying to watch these illicit copulations unfold for herself. This was Young's third year; so far, she'd managed to see it happen only twice.

  Young and I ambled around for half an hour, maybe more. Then she pointed and, in a monotone, said, "So, that's a female-female pair." We crouched and watched the two birds, numbers 169 and 983. 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 cell phones, clacking their beaks or stomping. But most of the time, they didn't do much at all. "I've spent a lot of my career watching animals not have sex," Zuk later told me.

  Homosexual activity is often observed in animal populations with a shortage of one sex—in the wild but more frequently at zoos. Some biologists anthropomorphically call this "the prisoner effect." That's basically the situation at Kaena Poi
nt: there are fewer male albatrosses than females (although not every male albatross has a mate). Because it takes two albatrosses to incubate an egg, switching on and off at the nest, a female that can't find a male (or maybe, Young says, who can't find "a good enough male") has no chance of producing a chick and passing on her genes. 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. From a strict Darwinian perspective, Young told me, "it doesn't pay for one bird to incubate the other's egg unless her partner is going to let her egg be incubated the following year." But presumably, neither female bird knows whether an egg is hers or the other bird's, much less whether it's fertilized or not. A Laysan albatross just knows to sit on whatever's under it. "They'll incubate anything—I have a photo of one incubating a volleyball," Young said.

  And these were only preambles to more questions. With the male of an albatross pair replaced by another female, every step of the species' normal, well-honed process for fledging a chick seemed suddenly to present a fresh dilemma. 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. And that's the whole point for Young: it's the complexity and apparent flexibility of the species that fascinates her—the puzzle those female-female pairs create at Kaena Point just by existing. She's not trying to explain homosexual behavior. She's trying to explain the albatross. And that's why the rest of the world's politicized reaction to her work caught her by surprise.

  Many people who contacted Young after the publication of her first albatross paper assumed she was a lesbian. She is not. Young's husband, a biological consultant, was actually an author of the paper, along with Brenda Zaun (who is also not gay, for what it's worth). Young found the assumption offensive—not because she was being mistaken for a gay person 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. Several people I spoke to told me that their own sexual identities helped spur or maintain their interest in the topic; Bruce Bagemihl argued that gay and lesbian people are "often better equipped to detect heterosexist bias when investigating the subject simply because we encounter it so frequently in our everyday lives." With a laugh, Paul Vasey told me, "People automatically assume I'm gay." He is gay, he added, but that fact didn't seem to detract from his amusement.

  In retrospect, the big, sloshing stew of anthropomorphic analyses that Young's paper provoked in the culture couldn't have been less surprising. For whatever reason, we're prone to seeing animals—especially animals that appear to be gay—as reflections, models, and foils of ourselves; we're extraordinarily, and sometimes irrationally, invested in them.

  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. The zoo's penguin keeper, Anthony Brown, told me he received angry e-mail, accusing him of separating the pair for political reasons. "Penguins make their own decisions here at the San Francisco Zoo," Brown assured me. And while he stressed that there is no scientific way of determining if animals are "gay," because the word connotes a sexual orientation, not just a behavior, he also noted that, this being the San Francisco Zoo, "there's definitely a lot of opinion here, internally, that we give in and call the penguins gay." Another male-male penguin couple who fostered a chick at the Central Park Zoo was subsequently immortalized in 2005 in the illustrated children's book And Tango Makes Three. According to the American Library Association, there have been more requests for libraries to ban And Tango Makes Three every year than any other book in the country, for three years running.

  What animals do—what's perceived to be "natural"—seems to carry a strange moral potency: it's out there, irrefutably, as either a validation or a denunciation of our own behavior, depending on how you happen to feel about homosexuality and about nature. During the Victorian era, observations of same-sex behavior in swans and insects were held up as evidence against the morality of homosexuality in humans, since at the dawn of industrialism and Darwinism, people were invested in seeing themselves as more civilized than the "lower animals." Robert Mugabe and the Nazis have employed the same reasoning, as did the 1970s antigay crusader Anita Bryant, who, Bruce Bagemihl notes, claimed in an interview that "even barnyard animals don't do what homosexuals do" and was unmoved when the interviewer pointed out what actually happens in barnyards. On the other hand, an Australian drag queen known as Dr. Gertrude Glossip has used Bagemihl's book to create a celebratory, interpretive gay-animal tour of the Adelaide zoo, marketed to gay and lesbian tourists. The book was also cited in a brief filed in the 2003 Supreme Court case that overturned a Texas state ban on sodomy and in a legislative debate on the floor of the British Parliament.

  James Esseks, the 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. It's totally beside the point, he said; people should not be discriminated against regardless of what animals do. (In her book Sexual Selections, Marlene Zuk writes, "People need to be able to make decisions about their lives without worrying about keeping up with the bonobos.") That being said, Esseks told me, polls show that Americans are more likely to discriminate against gays and lesbians if they think homosexuality is "a choice." "It shouldn't be the basis of a moral judgment," he said. But sometimes it is, and gay animals are compelling evidence that being gay isn't a choice at all. In fact, Esseks remembers reading a brief mention of animal homosexual behavior during an anthropology class in college in the mid-1980s. "And as a closeted guy, it made a difference to me," he told me. He remembers thinking: "Oh, hey, this is quote-unquote natural. 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. "I guess some of these animals could actually be quote-unquote making a choice," he said. How could we, as humans, ever know? "Huh," he said. "I'm just stopping to think that through. I'm not quite sure what to do with that." Esseks had stumbled right back into what he originally identified as the underlying problem. Those wanting to discriminate against gays and lesbians may have roped the rest of us into an argument over what's "natural" just by asserting for so long that homosexuality is not. But affixing any importance to the question of whether something is natural or unnatural is a red herring; it's impossible to pin down what those words mean even in a purely scientific context. (Zuk notes that animals don't drive cars or watch movies, and no one calls those activities "unnatural.") In the end there's just no coherent debate there to have. Animal research demonstrating the supposed "naturalness" of homosexuality has typically been embraced by gay rights activists and has put their opponents on the defensive. At the same time, research interpreted—or, maybe more often, misinterpreted—to be close to pinpointing that naturalness in a specific "gay gene" can make people on both sides anxious in a totally different way.

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nbsp; In 2007, for instance, the neurobiologist David Featherstone, at the University of Illinois at Chicago, and several colleagues, while searching for new drug treatments for Lou Gehrig's disease, happened upon a discovery: a specific protein mutation in the brain of male fruit flies made the flies try to have sex with other males. What the mutation did, more specifically, was tweak the fruit flies' sense of smell, making them attracted to male pheromones—mounting other males was the end result. To Featherstone, how fruit flies smell doesn't seem to have anything to do with human sexuality. "We didn't think about the societal implications—we're just a bunch of dorky biologists," he told me recently. Still, after publishing a paper describing this mutation, he received a flood of phone calls and e-mail messages presuming that he could, and would, translate this new knowledge into a way of changing people's sexual orientations. One e-mail message compared him with Dr. Josef Mengele, noting "the direct line that leads from studies like this to compulsory eradication of gay sexuality ... whether [by] burnings at the stake or injections with chemical suppressants. You," the writer added, "just placed a log on the pyre." (Earlier that year PETA and the former tennis star Martina Navratilova, among others, were waging similar attacks on a scientific study of gay sheep, presuming it was a precursor to developing a "treatment" for shutting off homosexuality in human fetuses.)