How an Amazon Tribe Reproduces Without Males

Deep in the Amazon lives a tribe of lesbians who reproduce without the involvement of penises, sperm, or any males at all.

Whiptail lizards, Cnemidophorous uniparens, lost all of its males somewhere along the evolutionary cycle. Females now reproduce by female-female sex. As described in Aarathi Prasad’s Like A Virgin: Exploring the Frontiers of Conception:

While the lizard is on top, it will intermittently rub its cloaca against the back of the passive female, stroking the back and neck with its jaws and forelimbs. The active female then grasps the back of the neck or shoulder of the passive female in its jaws and begins to curve and force its tail beneath the others’ tail, so that the cloacae of both are brought into close contact, somewhat as a male lizard would so in order to erect one of its two penises through its cloaca.

Once the orifices of both females are in contact, the courting female shifts its jaws to grip the lower half of the mounted females body. This forces the couple to adopt the contorted posture characteristic of mating lizards of opposite sexes.

Female-on-female Whiptail lizard action in the Amazon

Obviously questions remain. We do not know how this female-on-female sexual act causes the eggs in the passive female to “activate” as if fertilized and begin dividing into embryos, and we do not know if this pseudo-copulation is required to start the process. There is evidence of solo females reproducing in captivity without another female’s assistance.

We also do not understand how this lizard passes on DNA correctly. Typical sexuality combines half the maternal and and half the paternal DNA to give the child a new full set, but these lizards start with twice the normal DNA so halving it again gives their children a full set.

Once again, God and Mother Nature laugh at our formerly simplistic ideas of how sex works.

* A cloaca, by the way, is the name for the vent in the rear of many birds, fish, mammals, reptiles and others that serves as the single orifice for the intestines, urinary tract, and reproduction. Descriptively enough, the word comes from Latin, meaning sewer.

Just Because: The Weirdest Penis on the Planet

For those who think life only works one way, I give you: the Tasmanian Echidna and his four-headed penis.

God certainly does delight in diversity.

The weird four-headed penis of the Tasmanian echidna

(click to embiggen, if you dare)


How Bisexual Calamari Reproduce

One of the weird things about studying the bi- and homo-sexuality of animals is realizing how much I don’t know about their hetero-sexual practices. Take squid for example. How do squid have sex?

It turns out male squid who live in the deep dark only occasionally swim past each other, and when they detect another hot little squiddy number cruising past…

…the male ejaculates a packet of sperm at the mating partner, and the packet turns inside out, essentially shooting the sperm contained in a membrane into the flesh of the partner, where they stay embedded until the female (if the shooter has been lucky) is ready to fertilize its eggs. (NYT)

Scientists in the Monterrey Bay Aquarium reviewed years of undersea videos of squid behavior and found 39 images where they could tell the sex of squid, 19 females and 20 males. Of these, 9 males and 10 females had embedded sperm. So what we learn is: squids shoot their sperm at all passing squid, male or female.

The scientific paper announcing these results, “A shot in the dark: same-sex sexual behavior in a deep-sea squid,” hints at a controversy within. Why does this happen? Scientists split on the motivation of same-sex sexuality in animals. Often, scientists assume that animals that have sex with the same-sex are just dumb, that squid, among others, cannot determine the sex of other squid. This explanation strains credulity and tears at the rationale for a procreative drive. Increasingly we understand that same-sex sexuality also serves a purpose, otherwise evolution would weed it out as wasteful misfires.

Why do male squid fire their sperm packets at other male squid? The question remains unanswered.

(FYI, calimari is just Italian for squid, but sounding more delicious, it is the more common name on restaurant menus, where you and I are most likely to run into it.)

And Tango Makes Three: A Story of Gay Penguins

After the success of the movie March of the Penguins, which so emphasized the heterosexual triumphs of Antarctic penguins, it is hard to believe a couple of male penguins could became so famous. Along with the indomitable marchers, a pair of gay penguins of the Central Park Zoo are also part of history. The story of their little family is immortalized in the charming children’s book, And Tango Makes Three. It is a lovely little story of two gay dad’s, Roy and Silo, and the successful raising of their adopted egg, Tango.

Sadly, lifelong relationships are rare in nature, too. As the New York Times announced:

The two male chinstrap penguins had found each other in the big city. They had remained faithful. They had even raised a child. But then, not too long ago, they lost their home. Silo’s eye began to wander, and last spring he forsook his partner of six years at the Central Park Zoo and took up with a female from California named Scrappy. Of late, Roy has been seen alone, in a corner, staring at a wall.

Poor Roy. Let’s all hope he finds new love some time soon.

How Homosexuality fits into Evolution

Charles Darwin

One of the great questions about homosexuality in humans and animals is the question of how it serves procreation and survival. Most specifically, why do animals engage in non-reproductive sexual behaviors? 

Researchers Nathan Bailey and Marlene Zuk provide a variety of answers in their paper Same-Sex Sexual Behavior and Evolution (pdf). It offers a wonderfully brief (7 pages of text) but highly informative academic perspective on the subject. They include a varied list of examples of how same-sex sexuality benefits various species, with some really fascinating examples.

Also included in this paper are useful suggestions for standardizing nomenclature for same-sex sexuality in animals. I don’t follow their structure, but then, I’m not aiming for the kind of linguistic precision scientific papers require.

Gender Variation In Animals, and Evolution’s Rainbow

If the book Biological Exuberance is about gay animals, then Evolution’s Rainbow: Diversity, Gender, and Sexuality in Nature and People is about the full lesbian, gay, bi, transexual, and intersex spectrum.

Joan Roughgarden is an evolutionary biologist at Stanford University, and speaking from her personal experience as a transsexual, she analyzes the staggering variety we see in the animal kingdom. Sometimes too dense for the casual reader, it is nonetheless a fascinating and important book. She’s particularly insightful on the rainbow of gender variations both in animals and humans, proposing myriad new and provocative perspectives.

I love finding out how mind-bending the natural world is. God or Mother Nature or whoever is in charge certainly has a sense of humor and a profound devotion to diversity, and this book is an amazing job of trying to explain how it all works and why.

Biological Exuberance: An Encyclopedia Of Gay Animals

The best overview on gay animals is from the NY Times Magazine, Can Animals Be Gay?, but the definitive work is Bruce Bagemihl’s Biological Exuberance: Animal Homosexuality and Natural Diversity. With over 700 pages of detailed information, including sketches and photographs, he provides tons of detailed information. It is hard to express what a comprehensive and entertaining work this is, while staying scientifically rigorous. Plus the portrait on the cover is amazing.

Just for fun, here is the brilliant Ricky Gervais mocking Biological Exuberance. Funny stuff, but his comment at the end about the book’s sketches is unfair, as there are plenty of photos too.

Can Animals Be Gay?

Laysan Albatross doing the breeding dance

Strictly speaking, there are no gay animals. “Gay” is an identity, and we can never know how animals self-identify. Using the term more loosely, there is a lot of homosexual behavior in the animal kingdom, so much so that some scientists believe it may exist in every species. To those who say homosexuality is unnatural, nature disagrees. As the homophobia of our society decreases, our ability to see same-sex sexuality as it actually occurs in nature increases.

The most readable overview on the topic comes from a long New York Times Magazine article, Can Animals Be Gay? Framing the question with a discussion of lesbian Laysan Albatross, the author does a nice job of teasing out the difference between same-sex sexuality and gay identity, and the political forces that shape the discussion.

Girl-On-Girl Bonobo Action And The Location Of The Human Clitoris

How is this for provocative… the location of the human clitoris may be explained by lesbian sex in bonobos, a smaller form of chimpanzees and the animal species genetically closest to humans.

Mr. Bonobo (photo by Ltshears via Wikimedia Commons)

Bonobos are fully bisexual in a matriarchal society, and about half of their sex is same-sex. Also, they have a lot of sex, averaging once every two hours, and twice that often if the relationship is new. Female bonobos are particularly sexual with each other. One female will wrap her arms and legs around another, face to face, staring into each others eyes as they rub their genitals together, screaming and grimacing until they climax. Females also have sex by rubbing their butts together or mounting the other from behind. Males have many ways to interact as well including fondling each other, performing oral sex, and engaging in the descriptively named “penis fencing” which lead to ejaculation.

Interestingly, numerous studies show that bonobos maintain a peaceful society by using sex as an alternative to conflict in their social relations. When researchers put a new and intriguing object into a cage with two female bonobos, they will often have sex with each other before they approach the gift, presumably for stress release.

Meanwhile, in humans, one of the puzzles of human physiology is why the female’s main sensory spot is located separately from the place of direct sexual contact. In males the pleasure center is at the end of the penis, which is why men can happily stick it into just about anything. This motivates men to have sex with women–he derives pleasure from putting his cock into a vagina. But the female is not similarly wired for direct pleasure in intercourse. The orgasmic functions are particularly complex, largely because of the clitoris’s location. But why?

One answer is that the male is already motivated for sex and the resulting procreation, leaving the female body free to evolve for other purposes. The famous primatologist Frans de Waal wrote in 1995, “The frontal orientation of the bonobo vulva and clitoris strongly suggest that the female genitalia be adapted for this [frontal] position.” In her book Evolution’s Rainbow, Stanford biologist Joan Roughgarden notes that,

From the standpoint of female reproduction, little is gained by placing the clitoral neurons near the vagina to further same-sex mating when males are well motivated for intercourse anyway. Instead, the pleasure neurons are shifted to a location that promotes same-sex mating and may yield more effective same-sex bonds, increasing overall Darwinian fitness at no reproductive cost.

(photo by Malloreigh via Flickr)

Roughgarden also notes that Bonobos are one of the few mammals that have heterosexual sex face-to-face. So from the location of the Bonobo female clitoris, we derive that Bonobos evolved bodies that promote same-sex bonding resulting in face-to-face heterosexual sex.

The mind reels. Could it be that human females evolved a frontal clitoral pleasure center because female-female sexual bonding was so vital to our development? Do human males favor the missionary position because of the ways lesbian bonding affected female bodies? And most importantly to men who want to please their partners, is the clitoris separated from the vagina for reasons that have nothing to do with men? This explains a lot of male frustration in chasing elusive female orgasms, as men are fighting a battle nature rigged for the other team. We can conclude that if men get pleasure wherever they put their penis, and women are designed to find pleasure each other, we end up with a same-sex twist on a classical formulation: men sow their seed, and women bond…with each other.

Overwhelming as it seems, every human female body may be a testament to the power and importance of same-sex bonding in women.

The True Proclivities Of That Great American Symbol, The Buffalo

American Indian Head nickel, reverse

The American Bison, commonly called the Buffalo, is North America’s largest land mammal, the majestic symbol of the Great Plains, and very, very gay. American Bison males mount other males more often than they mount females, especially when young. Even when females are available, many male Bison choose other males as sexual companions. In the end, females only mate with bulls once a year, but males may mount other males several times a day during rutting season. More than a quarter of the males do not have sex with a female during rutting season, and 15 percent of females a year do not breed.

The Lakota people called these animals pte winke, or like a woman, a term they used for men who where the same way, thus tying the animal behavior to similar human behavior. Same-sex behavior is seen in European Bison, and when in heat, 15-20 percent of Water Buffalo females are mounting other females.

It appears that American Bison are not an good example for those who say homosexuality means the end of a species. I think it was human hunters who nearly achieved that feat.

Finding Nemo, And True Clownish Gender

Clown fish home life

The world’s coral reefs are the greatest producer of diversity on the planet, and that diversity includes gender variation.

In the wonderful Pixar movie Finding Nemo, Nemo’s mother is killed in the first scene. The rest of the movie is about the relationship between the surviving father and son clown fish.

Except that is not what happens for real clown fish. Real clown fish switch genders. As portrayed in the movie, clown fish live in a single anemone in monogamous breeding pairs of one larger female and a smaller male, along with some juveniles. However, in real clown fish lives, if the female dies, the adult male changes into a female, and one of the juveniles becomes an adult male. So… Nemo’s father should have become the larger female, and Nemo should have become his father’s, now wife’s, husband. That certainly would have made a more surprising movie.

I imagine Pixar had some lively meetings talking through the human-like story they wanted to tell using fish who have a very different idea of family building.

Gay Dolphins

OK, lets be honest. Is anyone surprised that dolphins are gay? They seem so playful and full of life, their sex life has to match up somehow. Fact is, it does.

Most dolphins are highly experienced at sexual play. As youngsters they play in same-sex groups, and as they grow into adolescence they explore their sexuality together, forming social bonds that often last through their lives.

Pink Amazon River Dolphin

My one closer encounter with dolphins was, strangely enough, in the Amazon jungle. It was my first day on the Rio Negro, a warm, inky black river that runs through some of the most isolated parts of the Amazon. Our jungle boat pulled onto a sandy beach and we broke from the heat by slipping into the silky water as freshwater dolphins swam around us. More than we could see them, we could hear the dolphins hunting through the riverside brush, splashing and shaking the bushes in the flooded rain forest. Dolphins are a good sign if you want to go swimming in the Amazon, as it means there are no Piranha around. Dolphins don’t like Piranha, and they have sonar to detect the fish in the waters around them.

(As if swimming in a dark Amazon river isn’t weird enough, the day went all wonky on me when a larger boat full of local family and friends pulled up farther down the same beach for a barbeque. Their music blasted out of huge speakers, and I swam back to our boat to a thumping dance remix of Mama Cass’s California Dreaming. We cannot escape American culture, even deep in the Amazon.)

Heterosexual dolphin sex is achieved by swimming belly to belly, and much homosexual sex is the same, with males penetrating their male partner’s genital slit or anus. Now “genital slit” is an interesting concept, illustrating how little I understand sex in animals, even other mammals. The genitals of both dolphin sexes reside up inside a slit which closes around them to achieve that smoothly streamlined profile. This little design feature also allows sexual partners of either sex to probe the slit with their beak or fins.

In addition to vanilla sex, dolphins can be really frisky. They love to rub each other, swimming stomach to stomach or alongside so they touch, and much of this contact is with other dolphins of the same sex. Believe it or not, dolphin orgies are quite common, ranging in size from 3-4 to dozens of same-sex animals cavorting together. Sexual play among dolphins can go on for hours. Another variation is multiple males, often bonded since youth, pursuing one female, while pleasuring each other along the way.

The Amazon River Dolphin is light blue, or more amazingly, pink. They have a long narrow beak with little rows of teeth, and a bulbous forehead. Even more colorfully, Amazon River Dolphins also practice homosexual penetration of a partner’s blowhole, one dolphin above the other, the world’s only known example of nasal sex! Whoa, right?

Female Spinner Dolphins add one more position that is strikingly visual – a female positions her genital slit or vulva over a lower partner’s dorsal fin, and they swim together in that position. That has to be one wild ride.

We know that dolphins have complex communication systems and intricate social relations. It also appears that dolphin sex is about a lot more than procreation.

(All photos by Preston)