Bitch: On the Female of the Species

by Lucy Cooke

The anatomical bible Gray’s Anatomy was just one of many to remove the clitoral label from their diagram of female genitalia. Other textbooks significantly undersold the clitoris’ size, the extent of its nerve supply, or only deigned to mention the external glans, accompanied by a cursory explanation of its form being merely a ‘small version of the penis’. It wasn’t until 1998 that the pioneering Australian urologist Helen O’Connell published the first detailed anatomy of the human clitoris and began a noisy campaign for accuracy in medical texts. The rest of the animal kingdom lags way behind, despite the fascinating wealth of clitoral diversity out there,

female bonobos, our closest ape relatives, have a clitoris that’s positioned to facilitate mutual stimulation with other females. In humans the clitoris sits outside the vagina, which seems rather inconvenient when you know that in the majority of mammals the clitoris is positioned inside the vaginal entrance, where it can be easily stimulated by the penis during sex.

Sex, like eating, is essential for life. So, why should it not feel good?

It turns out even female insects enjoy sex, if it is done right. In the bush cricket, Metrioptera roeselii,

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. Seduction starts with the farmer stimulating the sow with a fist, moves on to massaging her hips and finishes with the farmer sitting on her back to mimic the weight of the mating male on her.

In some primates the degree of sperm uptake has been linked to contractions associated with female orgasm. During climax, the release of the hormone oxytocin causes the uterus and oviducts to contract resulting in the ‘upsuck’ of sperm, which significantly accelerates their passage to the egg. A study of captive Japanese macaques, Macaca fuscata, found that females are more likely to achieve orgasm-like responses when mating with high-ranking, socially dominant males, suggesting preferential sperm uptake for these males.

The researchers concluded that female orgasm wasn’t a by-product of male orgasmic capacity or a means of reinforcing the pair bond, as suggested by Desmond Morris. Instead evidence suggested that, amongst humans, orgasm is more likely a cryptic means of selecting a high-quality sire for a woman’s egg. They propose that, just like those socially monogamous fairy wrens and hooded warblers from chapter three, ancestral human females may have pursued a mixed reproductive strategy, choosing partners based on investment potential and then sneaking off during ovulation to have orgasmic sex with high-quality males. A cryptic copulatory mate choice mechanism would allow females to exert some control over paternity, even if their sexual choices were constrained by familial influence or sexual coercion.

The more we investigate the female reproductive tract, the more ownership a female gains over her fertilization rights, and the more ridiculous the idea of an all-important ‘sperm race’ becomes. It turns out that mammalian sperm aren’t even capable of fulfilling their biological function without female intervention. They can’t actually fuse with the ova without a period of activation known as capacitation. This is under female control and involves chemical alterations of the sperm, probably involving uterine secretions. But guess what? We don’t know much more because it’s not really been studied.

Ova have long been considered the very epitome of female passivity; their large size and sedentary nature, in comparison to the small and mobile sperm, the very source of sexual inequality (as discussed in chapter three). Textbook descriptions of fertilization take the form of a biological fairy tale, with the helpless princess ovum waiting listlessly for her heroic sperm prince to battle his way to her rescue and awaken her from her lifeless slumber. But there is growing evidence that the egg can actually influence which sperm gets to enter, regardless of which one ‘won’ the race.

Sperm removal has also been posited as the driver of penis shape in humans. It has been suggested that the glans of the penis might be shaped to move previously deposited sperm away from the cervix during thrusting. Consistent with the view of the human penis as a ‘semen displacement device’, two surveys of college students showed that sexual intercourse often involved ‘deeper and more vigorous penile thrusting’ following periods of separation or in response to allegations of female infidelity.

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.

Dolphin sexual aggression isn’t restricted to other dolphins. There have been numerous reports of innocent victims from other species, most notably humans. In a scene reminiscent of Jaws, the mayor of a French seaside village on the Bay of Brest was forced to impose a ban on beach swimming during August high season when a sexually frustrated dolphin named Zafar began sexually harassing a series of beachgoers.

Most ironic of all, for a Catholic man of the cloth, he also developed the world’s first prophylactic sheath, as a protection against syphilis. He used a small linen cap drenched in a solution of salt and herbs, and sometimes milk, to cover the glans of the penis. The soggy contraption was held firm by a pink ribbon, so that it would ‘appeal to women’.

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.

Manu National Park, in the depths of the Peruvian Amazon. A full day’s journey upriver from any kind of civilization, this vast roadless wilderness is home to arguably the richest biodiversity on the planet – much of it unknown to science – plus a couple of dozen zoology geeks running around like kids in a candy store desperately trying to document and make sense of it all.

(Aotus nigriceps) wins the prize for being the most enigmatic. These miniature primates, roughly the size of a small squirrel, hide out high up in the canopy and aid their secrecy, as the name suggests, by being the world’s only nocturnal monkey. They live in family groups and are, unusually for primates, monogamous. Pairs will have just one baby a year – a ball of dense fluff that fits in the palm of your hand and could have been pumped out of a Japanese kawaii factory – all eyes and devastatingly cute.

The commitment to childcare demonstrated by owl monkey fathers is admittedly not the norm amongst mammals

Once females are liberated from the physiological responsibilities of pregnancy and lactation, as in the rest of the animal kingdom, dads become much more devoted. Amongst birds, bi-parental care represents the overwhelming majority, with 90 per cent of avian couples sharing the load. Slide back along the evolutionary scale and paternal care becomes not only more common, but customary. Amongst fish, it’s single dads that do all the nursing in almost two thirds of species, with mums doing little more than donating eggs before disappearing for ever. Some, like the male seahorse, even give birth.2

‘The circuitry facilitating parental behaviour is the same in males and females,’ O’Connell told me. So it’s not that one sex is programmed to instinctively provide care, it’s just that one does it. But both retain the brain architecture to drive the care instinct. Which is something of a body blow for the idea of a unique maternal instinct, in frogs at least.But what about mammals, where the lion’s share of parental care is often provided by the female and males can be, well, somewhat less inclined to nurture?

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.

Dulac discovered there are two groups of neurons – one that drives parental behaviour (galanin neurons) and another that drives infanticidal behaviour (urocortin neurons) – and they project directly on to one another. Stimulating one inhibits the other, so the behaviours are mutually exclusive –

Clearly the impulse to care-not-consume would be pretty helpful for this, the parenting equivalent of sucking a gobstopper for weeks on end and trying not to chew.3

As Dulac sees it, both strategies are essential for the survival of the species. ‘You and I are alive today because some of our ancestors used their galanin cells to nurture our ancestors, but also because there were these urocortin cells that allowed mum to decide whether it was a good time to have babies or not. Without them she might have died,’ Dulac told me. ‘I think it’s important to remember that.’

A deeper understanding of the full neural circuitry of parenting may eventually help with the treatment of psychiatric disorders associated with motherhood. ‘What is extremely striking is the testimony of women with postpartum depression; they have these obsessive thoughts about harming their children. It’s extremely disturbing for the women involved. They mostly don’t act on them, but those with psychosis sometimes do,’ she told me.

‘If you listen to the testimony of women who’ve killed their children, they don’t know what prompted them to do it, but they had this enormous instinct to do what they did and they have no explanation for it. You can imagine that this might be very similar to what’s happening in the brain of a mouse surrounded by danger and instinctively deciding to eliminate an infant.’

When the anthropologist Sarah Blaffer Hrdy went to Harvard in the 1970s, ‘Mothers were viewed as one-dimensional automatons whose function was to pump out and nurture babies.’ Just as females were thought to be passive and homogeneous when it came to courtship

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. Altmann could teach logic to Captain Spock. She had started her academic career as a mathematician at UCLA – one of only three women in her class – but was forced to quit when nobody in her faculty felt it worth their time to mentor a woman. Maths’ loss was zoology’s gain. Altmann arrived at field biology unencumbered by primatology’s phallocratic baggage and uniquely qualified to tackle the pitfalls of observational bias, which so plagued the science. She developed a method of sampling subjects at random and made sure each individual was watched for the same number of minutes

Cited over sixteen thousand times to date, it’s been described to me by one anthropology professor as ‘inadvertently, one of the greatest feminist papers of all time’, since it finally gave females the same airtime as males.

‘Some are more clueless than others,’ Altmann told me. ‘I remember watching one low-ranking first-time mother who would just walk into the middle of trouble. She’d try to keep feeding when others were examining her infant and you wanted to say, “No! No, they’re going to kidnap that infant.”’

‘The goal of successful parental care is that kids can be independent,’ Altmann told me. ‘A mother who’s not too protective has an infant who explores and develops their social world safely, but independently.’ Low-ranking females are put upon by just about everybody. Without the social standing to protect them and their baby, they compensate with what Altmann describes as ‘restrictive’ parenting, keeping their infant constantly within arm’s length. Restrictive mothering probably results in a better initial survival rate, as the infants are safer from predation and disease in the first few weeks. But they develop independence more slowly and place more demand on the mother’s critical resources, pushing her closer to that energetic cliff edge, and death.

Altmann’s team discovered that if they are able to forge strategic friendships with other baboons, either male or female, they can gain much-needed assistance when running the brutal Darwinian gauntlet. ‘We showed that those females who have friends live longer and their kids survive better,’ Altmann revealed to me over the phone. The

Baboon mums have another destiny-cheating tactic: they can unconsciously manipulate the sex of their offspring. Altmann discovered that at her Amboseli study site low-ranking females had more sons than daughters. This plays to their advantage. Female status passes down the maternal line and is fixed, so low-ranking daughters remain shackled to the disadvantage of their mother’s miserable status for life. Male baboons, on the other hand, fight one another to dominate their hierarchy, so their status is more fluid. Plus a son who manages to hitch his reproductive star to a more successful matriline and score himself a high-class daughter will secure a ticket to posterity for his offspring.

In contrast, high-bred female baboons produce more daughters than sons. Since their privilege is assured, daughters are a less risky gamble and,

Exactly how baboon mothers, be they low- or high-ranking, manage to fix the genetic deck in favour of the ‘right sex’ isn’t yet clear. But in other sex-manipulating mammals, like coypu and red deer, their method is strategic abortion.

In the wild, gelada baboons will abort when a new dominant male takes over the group. Incoming males almost always kill any babies they didn’t sire, so terminating the pregnancy is a mother’s insurance policy against this almost inevitable infanticide and wasting any further reproductive effort on a likely dead end.

The goal of motherhood isn’t to nurture babies indiscriminately but for a female to invest her limited energy in creating the maximum number of offspring that survive long enough to reproduce themselves. There is nothing truly selfless about the job; it is absolutely selfish. A ‘good mother’ instinctively knows when to sacrifice all for her offspring and when to cut bait, which might even be after the infant is born.

When pursued by a predator, she can jettison the bigger joey from her pouch, lightening her load and allowing her to escape. Unable to keep up with its mother, a teenage joey will perish without milk or protection from its mum. While this may sound heart-breaking to a human, for the kangaroo no painful conscious decision-making is required: natural selection has already furnished her with a functioning plan B.The cessation of suckling will trigger her embryo-in-waiting to emerge from developmental dormancy and serve as a rapid replacement for the lost joey.

‘With mammals, the female is stuck with this infant and the infant is stuck with the mother and this was traditionally seen to be a major constraint,’ Altmann explained. ‘People focused on the constraint, but that’s just a piece of this story. It also provides an asymmetry in power in who influences the Next Generation, and I think that’s still gotten much less attention.’

Their vision of ‘the good mother’ challenged that of the natural Madonna and replaced her with a more authentic and complex female figure that’s ambitious, calculating, self-seeking and sexually assertive.

The afterglow of sex – that’s oxytocin encouraging you to bond with your sexual partner, however inappropriate.

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.

Oxytocin is thought to reduce anxiety and fear, helping a mother cope with maternal stress and priming her to valiantly defend her offspring against any potential threat.

Grey seal pups are weaned in just eighteen days on milk that is 60 per cent fat. During this time the mother cannot return to the sea to feed so she loses up to 40 per cent of her body weight. Her pups, meanwhile, treble in size.

‘I’ve seen mothers that give birth to their pup and literally abandon it the second it comes out of them. Their pup is trying to interact with them and they’ll just ignore it and roll over,’ Robinson told me. ‘Everything that the grey seal mother has to do for her pup is crammed into this brief eighteen-day period so there should be high selection pressure for only the best maternal care. So what is going on?’ Robinson found that oxytocin levels provided a reliable metric for predicting maternal behaviour in wild grey seals: mothers with high levels spend more time snuggling up to their pups and developing a strong attachment. Low oxytocin levels suggest a less secure bond, and the female in Robinson’s study with the lowest levels did indeed abandon her pup on the fourth day. Her oxytocin level was so low, in fact, it was comparable to that of a non-breeding female.

If the mother gets distracted during this critical period, say by chasing off a seagull that’s scavenging on her freshly birthed placenta, then oxytocin levels can remain at the level of a non-breeding female. ‘If for any reason they miss that bonding window, you can’t recreate it outside of giving birth or having a massive artificial dose of oxytocin injected into your brain. And that’s when you start to see these rejections,’ Robinson told me.

Robinson discovered that these high oxytocin mother–pup partnerships resulted in the fattest pups, but without costing the mother additional calories (so it can’t just be that they’re drinking more milk). ‘If a pup’s got high oxytocin levels then it should be motivated to seek out its mother and stay with her, which means spending less energy running around the colony getting into trouble. The pup could also be getting some sort of microclimate benefit from sheltering right beside its mother in these cold colonies.’

There is evidence in rats that the oxytocin levels experienced by nursing offspring affect their maternal style as adults – those with attentive mothers will go on to make attentive mothers. Variation in nursing style can also affect other social bonds in later life. A lack of infant care in prairie vole pups impacts the density and expression of oxytocin receptors in their brain, which results in compromised social behaviour as adults.

Prairie voles are normally monogamous but those neglected as pups failed to forge lifelong sexual bonds as adults, as well as displaying disrupted parenting skills, likely due to increased anxiety.

There is evidence that, following birth, human mothers demonstrate a unique ability to recognize different sensory cues – visual, sound and smell – from their own babies. In one experiment, mothers with an insecure attachment to their baby were shown to have low oxytocin levels. When shown photos of their babies crying, their dopamine reward systems didn’t fire in the same way as they did in women with secure baby bonds. Instead their brains showed increased activation in the area associated with unfairness, pain and disgust

Around 9 per cent of the ten thousand living species of birds and 3 per cent of mammal mums get much-needed help from what are referred to as allomothers, literally ‘other mothers’.