Bitch: On the Female of the Species

by Lucy Cooke

The female is exploited, and the fundamental evolutionary basis for the exploitation is the fact that eggs are larger than sperms,’ wrote my college tutor Richard Dawkins in his bestselling evolutionary bible, The Selfish Gene.

Yes, the doting mother is among them, but so is the jacana bird that abandons her eggs and leaves them to a harem of cuckolded males to raise. Females can be faithful, but only 7 per cent of species are sexually monogamous, which leaves a lot of philandering females seeking sex with multiple partners. Not all animal societies are dominated by males by any means; alpha females have evolved across a variety of classes and their authority ranges from benevolent (bonobos) to brutal (bees). Females can compete with each other as viciously as males: topi antelope engage in fierce battles with huge horns for access to the best males, and meerkat matriarchs are the most murderous mammals on the planet, killing their competitors’ babies and suppressing their reproduction. Then there are the femme fatales: cannibalistic female spiders that consume their lovers as post- or even pre-coital snacks and ‘lesbian’ lizards that have lost the need for males altogether and reproduce solely by cloning.

But Darwin was probably not the originator of this convenient sexual classification. He likely borrowed it from Aristotle, the father of zoology. In the fourth century BC the ancient Greek philosopher wrote the first ever animal almanacs: On the Generation of Animals was his treatise on reproduction. Darwin had certainly read this seminal academic work, which perhaps explains why there is a distinct whiff of familiarity in Aristotle’s partitioning of the sex roles. ‘In those animals that have… two sexes… the male stands for effective and active… and the female… for the passive.’

It’s fair to say that if Darwin was a contestant on Mastermind, his specialist subject would not be the opposite sex. Here was a man that married his first cousin Emma, only after drawing up a list of nuptial pros and cons. This revealing romantic inventory, scribbled on the back of a letter to a friend, has, to Darwin’s shame, been preserved, revealing his most intimate thoughts for all to judge in perpetuity.

These encounters were ‘the most aggressive behaviour observed during the year’, but they were not included in any dominance network as the perpetrators weren’t male. They were all female. The authors concluded that this ‘testy’ feminine behaviour must be hormonally driven.

Science, it transpires, is soaked in accidental sexism.

The most dangerous thing about sexist bias is its boomerang nature. What started as chauvinist Victorian culture was incubated by a century of science and then spat back into society as political weaponry, rubber-stamped by Darwin. It gave a handful of, notably male, devotees of the new science of evolutionary psychology the ideological authority to claim that a host of grim male behaviours – from rape to compulsive skirt chasing to male supremacy – were ‘only natural’ for humans, because Darwin said so. They told women they had dysfunctional orgasms, that they could never break through the glass ceiling thanks to an innate lack of ambition, and should stick to mothering

And fresh perspectives from the LGBTQ scientific community have been crucial in challenging zoology’s heteronormative myopia and the binary dogma. Biologists like Anne Fausto-Sterling and Joan Roughgarden, amongst others, have drawn attention to the stunning variety of sexual expression in the animal kingdom, and diversity’s fundamental role in driving evolution forward.

females and males are, in fact, far more alike than they are different. So much so, it can sometimes be hard knowing where to draw the line.

It does both in the female mole, giving her the evolutionary edge underground: extra digging power and added hostility for defending her pups and worm larder. It also gives her genitalia that are indistinguishable from the male’s: an enlarged clitoris variously described as a ‘phallus’ or ‘penile clitoris’ and a vagina that seals up outside of breeding.

amongst most invertebrates and many fish, amphibians and reptiles it is the females that often outsize the males.

The radical gender-bending life of the female spotted hyena was originally assumed to be the result of an excess of testosterone circulating in her blood. Androgens, the group of sex steroid hormones that includes testosterone, have been unambiguously branded as male: andro meaning ‘man’ and gen a ‘thing that produces or causes’. So the obvious assumption was that these big, belligerent female hyenas, much like the mole we met earlier, must be swilling with the stuff. But much to everyone’s surprise, the circulating levels of testosterone in adult female spotted hyenas do not rival those in males.

Mammal embryos, whether they’re female or male, all start off with a unisex kit of parts:

Jost established that high concentrations of testosterone in the male fetus, produced by the developing testicular cells, actively pushed an embryo down the path of male sexual development. In contrast, the creation of a female was seen as a passive process – the ‘default’ result of an absence of gonadal testosterone. Jost’s theory slotted in nicely with the widespread notion, popularized by Darwin, that females were generally passive and males active.

Thus testosterone became the executive director of sexual dimorphism; responsible for characteristics ranging from the hefty horns on the stag to the bull elephant’s raging musth and the male walrus’s fearsome size and temper.

At a conference in 1969, Jost explained: ‘Becoming a male is a prolonged, uneasy and risky adventure; it is a kind of struggle against inherent trends toward femaleness.’ The masculine journey was seen as a heroic quest worthy of investigation. In contrast, the now-famous French embryologist referred to females simply as the ‘neutral’ or ‘anhormonal’ sex type. Ovaries and oestrogen were considered irrelevant to our story: inert and insignificant. Our sexual development was unreactive and scientifically trivial. Females basically ‘just happened’ because we lacked the embryonic balls to be male.

‘There’s no such thing as a “male” hormone or a “female” hormone. It’s a common misconception. We all have the same hormones,’ Christine Drea revealed to me over Skype. ‘All that differs between males and females are the relative amounts of enzymes that convert the sex steroids from one to another and the distribution and sensitivity of hormone receptors.’

The functional genetic steps of how to actually make female reproductive organs are still poorly understood when compared to the male. This bias in our understanding comes from Jost’s famous but flawed theory of sex differentiation, which only ever explained how you differentiate a male and never questioned how the female is created.

The XY sex-determination system is best known because it occurs in mammals, along with some other vertebrates and insects.

These genes have the ability to create either ovaries or testes, but exactly which gonad they actually produce depends on a complex network of inter-gene negotiation.

‘It is overly simplistic to say that there’s a single

In an effort to clarify this complexity, Graves sent me an animation of a crazy machine with dozens of interconnected ratchets and cogs all whirring around with little blue balls pinging in between them, and occasionally being squashed and recreated. The passage of the blue balls through this jumbled mess is her idea of how these purportedly neat binary sex-determination pathways really work.

Graves has discovered that these sixty or so genes are, in fact, remarkably conserved across all vertebrates. Birds, reptiles, amphibians and fish all have more or less the same set of genes as mammals for creating a testis or an ovary. What differs, however, is the master switch that kicks off the pathways. In the platypus this turned out to be one of the genes that’s in the orchestra and has stepped up to the front to trigger the whole sex-determination process. ‘SRY is just one way of kicking off the pathway, but you can do it by really almost any one of these sex-determining genes,’

‘It turned out the human Y was losing about ten genes per million years, and there’s only forty-five genes left. So it doesn’t take Einstein to figure out at that rate we’re going to lose the entire Y chromosome in four and a half million years.’

Graves is confident her gloomy prophecy won’t spell the end of mankind. She’s certain that the human male would simply evolve a fresh genetic trigger for his gonads.

sex but also the sex appeal of leopard geckos. According to Crews there are five types of sex: chromosomal, gonadal, hormonal, morphological and behavioural. They don’t necessarily all agree with one another or even remain fixed for life. They are cumulative and emergent in nature, and can be influenced by genes or hormones, as well as the environment or even an animal’s life experience. This plasticity allows for the huge variety in sex and sexual expression that we see both within and between species.

Crews blames the Organizational Concept for promoting a rigid deterministic view of sex, which focuses on the differences between the sexes, reinforcing the binary concept and ignoring the glorious diversity of sexual characteristics found in nature.

Crews’ research estimates that 600–800 million years ago the only creatures in existence were these cloning egg-layers. Males did not arrive on the evolutionary scene until the dawn of sex, when gametes diverged in size, which Crews reckons was around 250–350 million years later. With

‘Maleness evolved as an adaptation to femaleness,’ Crews continued. ‘When males came along what they did was to facilitate reproduction in the female. To stimulate and coordinate the neuroendocrinological processes that underlie the shedding of gametes. Males are behavioural facilitators.’

So, in the gospel according to Crews: Eve wasn’t created out of Adam’s rib, it was the other way round. In the beginning there was female, and she gave rise to male. From this alternative evolutionary perspective, the ultimate answer to what is a female is: she’s the ancestral sex. Relics of this primal egg-layer exist within all of us. Which puts a fresh spin on males getting in touch with their feminine side.

The deep-sea angler fish Ceratias holboelli has taken this to an extreme. Males may be more than sixty times shorter and half a million times lighter – essentially little more than swimming sacs of sperm. Once the male has sniffed out a female from her leaking pheromones in the pitch-black depths, he will latch on to her with his mouth, physically fusing with her body for the rest of his life – the evolutionary embodiment of a clingy sexual freeloader. The female is thereafter in control of the male’s entire existence, including when he ejaculates his sperm. The Danish fisherman who discovered this intimate set-up in 1925 declared that ‘so perfect and complete is the union of husband and wife that one may almost be sure that their genital glands ripen simultaneously’. And they say romance is dead.

‘Most people blast white noise to disguise the sound of their footsteps as they approach the bird,’ Eric told me, ‘but I use AC/DC.’ How could I resist?

‘One of the things I love about studying these birds is they take themselves so seriously,’ Gail confessed to me in her lab at UC Davis. ‘It’s just totally ridiculous what they are doing – it’s obscene – and yet it’s deadly serious for them. This is the crux of evolution.

Descriptions of sage grouse leks have traditionally embodied androcentric typecasts. The birds made their dramatic debut on the ornithological scene with a male displaying his fully inflated sacs on the cover of Nature magazine in 1932. The author of the paper, R.Bruce Horsfall, took great delight in describing the males’ ‘queer antics’ but assumed their ‘rubbery plops’ must be directed at one another, and not the females. This view was upheld for most of the twentieth century, with scientific papers entering into lengthy discussions about the dominance hierarchy of the ‘master cocks’, with the hens’ ‘inconspicuous and passive’ behaviour demanding little attention.

Female choice may be one of the hottest subjects in evolutionary biology today, but it hasn’t always been that way.

‘It is shown by various facts… the female, though comparatively passive, generally exerts some choice and accepts one male in preference to others.’ Later, Darwin

Darwin’s controversial claim was that females were not only sexually autonomous but had the wherewithal to make decisions that shaped male evolution. This put the fairer sex in a very powerful role – a role that made most (male) biologists deeply uncomfortable. Men controlled women in Victorian England – not the other way around. The astonishing originality of Darwin’s new theory didn’t help its passage into cultural and scientific acceptance either.

This gave the Victorian establishment a whip to beat Darwin’s new theory with. According to the thinking of the time, only the upper classes could appreciate art or music, so it seemed utterly absurd that a female, let alone a lowly peahen, would be endowed with an aesthetic faculty. Beauty was God-given, so the idea that female sexual preference was the primary agent of its evolution was tantamount to heresy.

Things have changed. The sexual revolution of the 1970s and the impact of feminism on evolutionary biology have helped stir Darwin’s daring idea from its century-long slumber. The idea that females – from birds to fishes to frogs to moths – are able to make sensory evaluations and exercise mate preference

What makes a lek so special for students of sexual selection is that the females will go on to raise their offspring alone.

Thanks to Gail’s handicraft skills the resulting homespun robo-bird was actually incredibly realistic, apart from the wheels.2 These don’t seem to bother the males, however, who are an indiscriminate bunch.

The great bowerbird’s bower, for example, is like a house of illusions: objects are arranged according to their size to create a false perspective that makes the bower seem smaller and the male seem bigger than he really is.3 Female satin bowerbirds are less fussed about the size of their cock and more concerned about his ability to acquire blue trinkets.

Previous scientists had noted male animals paying attention to female signals during courtship. But Gail was the first to show that listening and responding to her cues was linked with the male’s mating success.

Courtship has traditionally been viewed as a black box in which males and females assort themselves according to the quality of a male’s trait and the strength of a female’s preference, with the process itself seen as obscure or irrelevant. Gail sees a lek more like a big open bazaar full of traders and buyers in a constant state of shopping and negotiating.

‘Sexual selection can drive the evolution of these flashy traits, but also this kind of social intelligence, these courtship tactics that are also an important part of competition for mates. So sexual selection might be a lot more powerful than we initially assumed,’ Gail explained. All this tactical negotiation requires cognitive power. Male satin bowerbirds have relatively large brains, are long-lived and undergo a strange seven-year adolescence which is spent impersonating the female. Juvenile males share the same green plumage as the females and Gail thinks that learning their complex lothario skills might explain this unusually long, cross-dressing developmental period, which is spent not only practising bower-building but being actively courted by adult males.

A study in 2009 that tested the male satin bowerbirds’ problem-solving skills was the first to show that cognitive performance is associated with mating success and females prefer the most nimble-minded male

This idea isn’t new. Darwin himself proposed that sexual selection could, in fact, be responsible for the exceptional evolution of human cognition – especially the more ‘self-expressive’ aspects of human behaviour, such as art, morality, language and creativity.The idea that female choice might have polished the human brain into brilliance would have been the ultimate blow to the Victorian scientific patriarchy – hitting them right between the eyes, where it hurt most.

Gail and her team name the birds after the patterns they trace via the white tips to their tail feathers, which are as unique as a fingerprint. Dick’s feathers resembled the shape of a penis, so they christened him Dick without knowing the extent to which the dominant cock would live up to his name.

I was in the Maasai Mara with Dr Ludwig Siefert, a lion specialist, who was demonstrating the use of audio playback in deciphering lion communication. This involved the two of us standing with our heads poking out of the top of his jeep, under the cover of night, pumping the sound of a dominant male’s roar into another lion’s territory, an audacious way to pursue scientific enquiry and which struck me as the feline equivalent of screaming, ‘Come and have a go if you think you’re hard enough,’ outside a rough pub at chucking-out time.

a female lion is known to mate up to one hundred times a day with multiple males during oestrus.