Bitch: On the Female of the Species

by Lucy Cooke

When she’s shedding her exoskeleton for the final time before adulthood, her unhardened body is vulnerable; she cannot move, let alone attack a male. It is at that moment the male makes his move and mates with her. It’s a successful strategy: copulations with moulting females resulted in 97 per cent male survival compared with only 20 per cent in conventional sex with a hardened adult female.

The opossum may have three vaginas but the elephant shrew has none – the female’s womb opens directly on to the outside world.

In later life, this Victorian matriarch was said to have spearheaded a campaign to rid the English countryside of the obscenely shaped stinkhorn mushroom – Phallus impudicus – because of the effect that seeing it might have on female sensibilities.

The year was 1979 and Jonathan Waage, an entomologist from Brown University, quietly published his succinct observations on the sperm-scooping, as opposed to delivering, talents of the damselfly penis. Brown demonstrated that the rows of stiff backwards-facing hairs at the tip of the phallus enabled the male to spring-clean the female’s reproductive tract, removing any lingering sperm left by rival males that might compete with its own.

Darwin had supposed that male competition finished once a male had won the female. But Waage’s discovery showed that their sperm continued to compete long after a male had ‘won’ his mate. This put genitals on the frontline of sexual selection and worthy of closer scrutiny. Suddenly the race to fathom all this phallic diversity became ‘one of evolutionary biology’s greatest enigmas’.

avian sex generally takes place using a multifunctional unisex hole called a cloaca. The male and female evert and momentarily touch cloacas in what’s known as a ‘cloacal kiss’ – a term which loses its charm somewhat once you know that ‘cloaca’ is derived from the Latin word for ‘sewer’.

some sixty-six to seventy million years ago the Neoaves, which includes over 95 per cent of the world’s birds, somehow lost their penis. This seems careless at best, but evolution must have its motives. Some have suggested it was for reasons of hygiene – prodding around in a sewer isn’t great for keeping clear of STDs (but many reptiles happily do it with their own penis/cloaca arrangement).

When the drake is poised to penetrate he pumps lymphatic fluid into his member, and the penis explodes out of his cloaca at 75 mph, unfurling itself in a third of a second like some kind of sinewy party hooter.

‘I think this is what is going on during the forced copulations; the female is non-receptive so she doesn’t wink and her vagina stays in this crazy convoluted state.’ When she is receptive, however, the female duck opens the lumen of the vagina so her mate can get further along her reproductive tract than unwanted males. She may not be able to choose whom she mates with but she can control the paternity of her eggs, which is, of course, the ultimate goal.

‘These forced copulations are so nasty and the female seems so helpless – they are small and can’t fight the males off. But it turns out there are other ways to fight them off that are subtler and the males can’t do anything about. Even though males are forcing themselves on her they’re unlikely to get paternity.

has rescripted this particular battle of the sexes and recast the winner as female. Her work demonstrates how you can’t judge a book by its cover; the duck’s hidden reproductive anatomy reveals a very different story to the one suggested by their outward behaviour. Female ducks are not passive victims but active agents driving their own evolution, along with that of males. Such antagonistic co-evolution is of course a conversation, or perhaps an argument, between the male and the female that plays out over deep time. And the only way to understand it is by paying attention to both sides of the story.

She suspects that the loss of the Neoaves’ penis is the product of female choice. Females have chosen less coercive males with smaller penises and, over millions of years of this selective bias, the penis eventually disappeared. The penis-free system is undeniably awkward for the male – it is all but impossible to fertilize the female without her consent.

In his pioneering book Female Control (1996), Eberhard presented the case that female genitalia – be they vaginas, cloacae or spermathecae – are far more than just inert tubes for ejaculate. They are active organs that can store, sort and reject sperm through their architecture, physiology or chemistry. Females can dump the semen of unappealing suitors, actively speed chosen sperm on a fast track to the ova, or let them languish in a tortuous maze of ducts.

‘I love Eberhard’s book,’ she told me, ‘but it gave the impression that female genitalia are not worth studying. That males are where all the action is.’

Brennan’s ambition is to create the world’s first physical library of animal vaginas to catalogue the taxonomic diversity of shape and function. She’s already on her way.

Dolphins are essentially like ducks in their genitalia.’ This is especially interesting, as dolphins have another key thing in common with ducks: forced copulations.

dolphins’ liberal attitude to sex has led to them being dubbed ‘aquatic bonobos’, with reference to the apes we’ll meet in chapter eight that use sex in a wide variety of social situations, and not just conception.

coalitions of male dolphins will aggressively herd and harass females for sex.

Human vaginas are known to change shape during sex, so recreating the mechanics of copulation with fixed structures was far from perfect. But Brennan said it was good enough to demonstrate how both the bottlenose dolphin and harbour porpoise penises become obstructed by the female’s labyrinthine pipes. That is, unless she is penetrated from a very specific angle.

The more we discover about female sexual anatomy, physiology and behaviour, the more centuries of perceived male dominance begin to wane. Females have evolved creative ways to control the insemination of their eggs, even when males are more powerful, numerous or forceful.

the clitoris evolved for sexual pleasure and there is huge variety amongst mammals, suggesting there are strong evolutionary forces at play. But compared to the penis, we know very little about its morphology or histology.

When Falloppio’s finding was shared, however, with the great physician Vesalius, the founder of modern human anatomy, it was swiftly dismissed. Vesalius proclaimed that ‘this new and useless part’ didn’t exist in ‘healthy’ women, and was only to be found in hermaphrodites. This inglorious misunderstanding set the stage for the next four hundred and fifty years, which saw the clitoris routinely lost, rediscovered and subsequently dismissed by the medical patriarchy.

In many manuals the clitoris was present in the early 1900s, and subsequently deleted mid-century, suggesting that its omission was perfectly intentional – a subconscious means of denying women sexual pleasure, perhaps.

Danish pig farmers know all about this. They’ve discovered that artificial insemination is more effective if preceded by manual stimulation of the clitoris, cervix and flanks. So they’ve taken a practical approach and developed a special five-step sow stimulation routine, with graphic images for guidance.

This sow seduction formula results in 6 per cent more babies than going in straight with a cold hard syringe, but may put some off a career in pig farming.

At the 2018 TetZoo conference I asked Albert Chen – a specialist in fossilized ancestral birds – what dinosaur penises would have looked like. His wide-eyed one-word answer: ‘Scary.’ For the curious (and brave), googling pictures of ostrich penises will illuminate Chen’s sentiment and suggest that the most terrifying thing about T-Rex may not have been his teeth.

rape amongst humans is a much more complicated phenomenon that can occur for complex psychological, social and cultural reasons that do not apply to the likes of ducks and bed bugs. This is a very important distinction to make. One that has eluded a handful of male evolutionary psychologists who have suggested that human rape is biologically determined by Darwinism. Such claims have been met with widespread criticism. The danger in suggesting a rapist lives inside all human males thanks to sexual selection has forced a strict avoidance of the human term when talking about animals.

Woman seems to differ from man in mental disposition, chiefly in her greater tenderness and less selfishness… Woman, owing to her maternal instincts, displays these qualities towards her infants in an eminent degree; therefore it is likely that she would often extend them towards her fellow-creatures. Charles Darwin, The Descent of Man, and Selection in Relation to Sex

Muqui’s unrelenting cries provided us with some guidance to his needs and he took up residence on our heads. Muqui was calmest clinging to a mass of hair, which made the prospect of potty-training especially onerous.

My maternal drive should have kicked in and transformed me into an intuitively wise and selfless nurse. But the truth was I felt quite traumatized by the experience – fretful, out of my depth, exhausted and, for the sake of my defiled and defecated-on hair alone, uninclined to repeat the whole sorry ordeal ever again. I was thirty-nine at the time and wrestling with whether I should be having children myself. My night with Muqui only reinforced my suspicion that I came from a long line of not terribly motherly females. If there was such a thing as maternal instinct, I was pretty sure I didn’t have it.

Using cutting-edge optogenetic techniques, Dulac was able to activate the galanin cells in virgin males on the verge of killing infants. Their transformation was instantaneous. The males started building nests, and carefully placing pups in them, which they then groomed and huddled protectively. ‘The male mice were “maternal” – they took care of pups in exactly the same way a mom would do, the only difference being that they couldn’t lactate.

‘If you look around, whether it’s in humans or in any animal, not all individuals behave the same. Not all males are equally aggressive. Not all females are equally maternal. There is enormous variability.’ Not only is this neural circuitry the same in male and female mice, but Dulac suspects it is shared by all vertebrates, including us.

‘What’s kind of heart-warming is that when I give talks about paternal and maternal behaviour my male colleagues just love the idea that the male brain has all it takes to be parental – it’s satisfying somehow,’ Dulac said.

Dulac’s work is the first time a complex social behaviour has been mapped out in the brain of a mammal. It is a discovery so significant that it won Dulac a prestigious 2021 Breakthrough Prize (the self-proclaimed ‘Oscars of Science’), which goes to show how academic respect for the study of motherhood has changed in the last fifty years.

I met Altmann at Hrdy’s walnut farm in northern California. The two primatologists are long-term conspirators, although, on the surface, quite different characters. Compared to her larger-than-life Texan host, Altmann, a no-nonsense New Yorker now in her eighties, is diminutive in stature, quiet and reserved. Her ideas have been no less radical, however. Her secret weapon has been an unswerving devotion to the geek god of impartial data. Yes, Altmann sparked a revolution through rigorous statistical analysis, which might not sound terribly sexy, but it was the only way to skew attention away from the dramatic allure of pugnacious male primates.

Not only were mothers considered to be of little theoretical significance to the male zoological establishment, they were also out of fashion with female scientists keen to embrace the nascent feminist movement. The study of motherhood was considered a retrograde move: ‘“the home economics” of animal behaviour’, as Sarah Blaffer Hrdy pronounced in her book Mother Nature.

For mothers, the timing of weaning is a close instinctual calculation of resources. Mistimed, it can lead to certain death for either mother, baby or perhaps both. Baboons, like all mothers that breed several times during their lifetime, must balance the investment in their current offspring against their own survival and future reproductive capacity. The average baboon is likely to spend 75 per cent of her life having babies – around seven in total, of which only two are likely to survive into adulthood.

The physical process of labour is stimulated by oxytocin in the bloodstream, but the stretching of the cervix and vagina during the birthing process itself triggers an almighty rush of oxytocin in the brain. The resulting delicious cocktail of natural opiates ensures the new mother is primed to bond with her newborn as soon as it enters the world. The act of suckling will bathe her brain in yet more oxytocin, so she basically becomes addicted to caring for her baby.

Catherine Dulac is investigating the impact of oxytocin on the galanin neuronal hub – the switch for parental care in both sexes that we met earlier in the chapter. She’s found that this parenting command centre does indeed have oxytocin receptors, but only in mothers. This accounts for a birth mother’s unique souped-up parenting response – she has both galanin and oxytocin neurons driving her behaviour. But the cuddle hormone, despite its reputation, is not the elusive trigger for this parenting switch, it merely complements it.

This second phase can drive the attachment in mums, dads, other more distantly related kin and even foster parents. It has been observed experimentally in virgin female rats, which are normally extremely hostile towards pups, ignoring or even devouring any they happen upon. But if a virgin is repeatedly exposed to pups, especially if she has a mother to learn from, this inexperienced au pair from hell stops killing and starts nurturing until eventually she’s as attentive as a birth mother.

most primate babies, with their big brains, take a long time to reach independence and demand years of intensive care. This makes having more than one at a time too tricky. Varecia females have an innovative solution to the problem: they make like birds and build nests high up in the canopy. These serve as communal creches for two or three separate litters, so working lemur mums can share the parenting load.

Bro-Jørgensen is the world’s leading (if not only) expert on the sexual politics of the topi. He has observed their annual rut for the last decade and uncovered a complex culture of bitch fights, con artists and bashful bulls that Darwin never dreamed of.

Breeding season is intense, as the females all come into oestrus for just one day of the year. This short fertility window leads to a twenty-four-hour frenzy of sexual activity. Bro-Jørgensen calculated that each female mates, on average, with four males, while some reached as many as twelve different partners in this limited timeframe.

The top bulls command terrain at the centre of the lek, and it is these studs that have females battling over their limited reserves. ‘It is not uncommon to see males collapsing with exhaustion as the demands of the females get too much for them,’ Bro-Jørgensen said.

Bro-Jørgensen discovered that male topi hotshots don’t mate indiscriminately, as Darwin would have predicted, but have instead adopted the female’s traditional choosy role in order to conserve their precious sperm. Their goal is still to mate with as many individuals as possible, but they deliberately choose the females they have mated with the least to maximize their chances in sperm competition.

Darwin’s blinkered yet highly influential view ensured that for the next hundred and fifty years studies of intrasexual competition focused on male competition for mates, and the combative potential of females was largely ignored by science. The resulting data gap on females then masqueraded as knowledge. It’s assumed females aren’t competitive, and theories are based upon that understanding – when the truth is we just haven’t been paying attention.

Naomi Langmore, professor of evolutionary ecology at the Australian National University, told me. ‘The textbook definition of birdsong is that it’s “complex vocalizations by male birds during the breeding season”.

This persistent all-male classification seriously ruffles Langmore’s feathers. For the last thirty years she’s been studying the complex vocalizations of female songbirds and fighting to get their voices heard. She’s part of a pioneering group of scientists who, tired of dogmatic androcentric definitions of birdsong, took it upon themselves to trawl through all the available scientific data to demonstrate that, far from being dumb, 71 per cent of female songbirds sing.

Songbirds are understood to have evolved in Australia some forty-seven million years ago. Given the prevalence of female birdsong in their place of origin, Langmore and co. wondered if they’d always sung. So they created an avian family tree to reconstruct the ancestral state and deduced that the earliest female songbirds were, indeed, a bunch of raucous divas.

Langmore’s discovery was indeed profound. It proved that female song wasn’t some recent evolutionary kink, found only in the tropics. Female songbirds had always sung. What’s changed is that, in some northern temperate regions, in the more recently evolved families of songbird, females have, for some reason, ceased singing. Which is a radically different evolutionary scenario than the framework proposed by Darwin.