Dagmar van der Neut – The Beast in Us 



  1. Who was the first one to have sex on this planet?
  2. Why do we have sex?
  3. How important are men?
  4. Why do we bend over backwards for love?
  5. Why are gorillas poorly endowed?
  6. Do men with small willies stand a chance?
  7. Are we monogamous by nature?
  8. Are men sex maniacs, while women remain chaste?
  9. Why don’t cockatoos have willies?
  10. Why do lovers argue so much?
  11. Do men long for their mother?
  12. Is love the result of calculations?
  13. Do cows have girlfriends?
  14. Why don’t people marry goats?
  15. When was love invented?
  16. How natural is an actively parenting father?
  17. How does one develop a fart fetish?
  18. Is homosexuality natural?



[pp. 49-66]

Chapter 5

Why are gorillas poorly endowed?

Some things can astonish you. It happened to me recently when, on a rainy afternoon in a scientific article by two German zoologists, I found myself looking straight at a crocodile’s crotch. The crocodile dick looked remarkably human. No scales, armour or anything threatening to make you think of a reptile. A rather flaccid and vulnerable little thing really, for such a bloodthirsty killing machine. To be honest I was slightly shocked.
Penises often come as a surprise. I know this from girlfriends of mine, but females in the animal kingdom are no less well advised to watch out. A three-kilo Muscovy duck looks innocent enough waddling about in a children’s zoo, but when he gets worked up, his forty-centimetre corkscrew penis shoots out of his cloaca like a coiled spring at 120 kilometres an hour. In response, the female Muscovy duck has developed a vagina that’s extremely hard to penetrate, researchers at Yale discovered not long ago. You can well imagine wanting to keep such a monstrous thing outside the entrance.
Dicks can have all kinds of surprising characteristics. Cephalopods like the octopus and squid use what’s known as a hectocotylus, a modified arm, to copulate. The female of the paper nautilus, for example, swims around in a paper-thin egg case while the male’s arm takes a handful of sperm, separates itself from the male and swims off under its own steam in search of the lady of its dreams. Having found her it creeps all by itself into her vaginal opening.
Bottle-nosed dolphins, those adorable creatures that leap out of the waves with such joyful vigour, have dicks that can smell. The females are thought to guide them by emitting a scent from their vaginas. The willy belonging to the Japanese swallowtail butterfly is equipped with another sense: it can see! When no longer able to detect any light it knows it must be in the right place.
It can get weirder still. French and Scottish researchers recently discovered that the lesser water boatman, a two-millimetre-long insect that lives at the bottom of ponds, puddles and swamps, sings with its penis to attract females. This is no subtle love song but totally over the top. He rubs his member, which is no thicker than a human hair, across his stomach to produce a number of decibels – 99.2 to be precise – comparable to a goods train thundering past. Fortunately the water mutes 99 per cent of his sexy serenade, so we can enjoy a swim without being deafened. Biologists have calculated that ‘The Singing Penis’ is the noisiest creature on earth, relative to its size.

Sometimes the surprise derives from misplaced expectations. Primatologist Frans de Waal, for example, says he quite regularly receives letters from women who want to go to bed with apes. It’s true. They offer their services for a scientific experiment of some kind. Gorilla males, those silverbacks that keep harems, are particularly in demand. It seems women are excited by the prospect of being subjected to a broad-shouldered primal force, taken by a growling Bokito. But what the women don’t realize, De Waal adds, chortling, is that gorilla penises are only three centimetres long – when erect! Such an assignation is fated to disappoint.
Anyone going in search of the longest penis in the animal kingdom will alight not on the robust gorilla or the mighty lion but the laughable barnacle. Those crustaceans that build white houses for themselves on mussel shells have two penises that each measure no less than twenty-two centimetres, a good thirty times the length of their bodies. Is that really necessary, you might ask. Yes, it is. If you can’t go off and visit the partner of your choice, like the stay-at-home barnacle, then such a length is pretty handy. The gigantic blue whale, incidentally, has the longest penis in absolute terms, at something approaching 2.5 metres, but the size of the sexual organ by no means always correlates with the size of its owner.

Why do some animals sport enormous cocks with turnips to match while others have midget dicks and a pair of marbles? There seems to be no logic to it. A chimpanzee is a quarter the weight of a gorilla, but its testicles are four times as heavy. As a proportion of its body weight, a gorilla’s sexual organ is only 0.02 per cent of the total, whereas a chimp’s accounts for 0.27 per cent. Why the disparity?
We all know that males have to compete for the favours of females. Every male wants access to the holy grail, that oh-so-rare and nutrient-rich ovum he needs in order to pass on his genes. This rivalry is self-perpetuating because the males who manage to reach the ovum contribute their competitive genes to the next generation. Less combative males are not in the race and they fail to pass on their peace-loving genes. The result is a world full of males trying to get one up on each other.
Much of their competition is played out before copulation takes place, on mating grounds and in discotheques. But the creativity of males is boundless when it comes to seeing off rivals. They don’t merely compete by clashing horns, showing their muscles or waving bank notes, they wage war at the micro-level, deploying the penis and sperm as weapons.
The common house fly, for example, proves a devoted lover. He releases his seed within fifteen minutes but carries on copulating for an hour, not merely to pleasure his sweetheart but to keep the door shut to other males. After all, the first male to copulate with a female won’t necessarily be the one that impregnates her. Many studies have shown that a second or third or even later male will father the progeny, so it’s crucial to ensure no one gets a chance to copulate immediately after you if you want to be certain your sperm will win out.
Those who got in there before you are rivals as well, so it’s worth making sure your sperm trumps theirs. In the 1970s, British evolutionary biologist Geoff Parker introduced the term ‘sperm competition’ for the battle between ejaculates that goes on inside the female’s body.
There are countless examples. Male fruit flies have a kind of poison in their semen that kills other males’ sperm and makes females so nauseous they no longer feel like having sex. The rove beetle, a common insect that inhabits our gardens, places a bag of sperm cells in the female’s sperm library, the storage facility for spermatozoa found in many insect females, which then partially explodes, blasting the sperm of its predecessors back out.
Some biologists believe that the penis serves not only to deliver sperm to the right spot but to drag away the sperm of possible rivals. Insects show most clearly of all that the cock can be nothing short of a weapon in the battle to reproduce. Damsel flies, whose stalk-like bodies and extended wings make them look very much like dragonflies, have pricks resembling mediaeval instruments of torture. Barbs, shovels, pincers: they all serve to keep the female in check and remove the sperm of any male who got to her first. Even the glans of the human penis is thought to be capable of dragging off the sperm of rivals.

To wage war at the level of the sperm cell, many animals deploy large armies that can overpower opponents and win pitched battles. If a male can manage to flush away all other sperm with his own semen tsunami, then his seed may be the first to reach the finishing line. In some animals the production of sperm increases when the smell of a rival male reaches them. Other animals simply ensure they always have a large number of spermatozoa to hand.
Here the gorilla’s miniprick raises its head again. To enter the sperm competition you need suitable tools: a vigorous penis that if necessary can drag off, kick out or shovel away the sperm of earlier visitors, or a hefty pair of testicles to produce plenty of sperm cells. Bokito the gorilla doesn’t need any of that. Why not? Because with his broad torso and colossal biceps he’s already won the battle. His harem includes most of the available females, and with him they lead a relatively quiet and faithful sex life.
In the case of the woolly spider monkey of Brazil it’s precisely the other way around. The females do it with everyone, and the males have such large testicles that biologists observing them initially thought they were suffering from elephantiasis, a disease that makes parts of the body swell to elephantine proportions. Woolly spider monkeys don’t have big muscles and they never fight each other, in fact researchers have watched several males amicably copulating with the same female, taking turns. All good friends together. Their sperm fight their battles for them.
A study comparing the sexual organs of different types of ape has shown that those whose females are the most licentious are the most generously endowed. The sexual organs of apes with loyal females are rudimentary stumps by comparison. The researchers concluded that the frills and fandangles on their penises were intended to help the females achieve orgasm, thereby increasing the chances of impregnation.
The size of its glockenspiel therefore turns out to be a good indication of the sexual mores of a species. The more faithful the females, the less the need for sperm competition and the smaller the private parts. Chimpanzee females are quite promiscuous compared to gorillas. They mate hundreds of times with different males before each pregnancy, and more than half their young will have fathers outside the group. Lo and behold, chimpanzee males have the largest testicles of all primates.
So what does that say about us? Humans fall between gorillas and chimps when it comes to the size of their balls. True, they have the longest penises of all the primates, but their testicles are relatively modest at twenty grams each. The implication? That human females aren’t as adulterous as chimpanzees but consistently faithful? No, that would be overstating the case.


Chapter 6

Are unassuming men on a losing wicket?

Thinking about alpha males, hotshots, machos and toughs, I suddenly felt sorry for the men reading this. Ordinary men, perhaps, who are not at the top of the pecking order, who don’t exactly excel at chatting up women and aren’t blessed with broad jaws and a torso to match. Men on the small side, maybe, or with crooked teeth; jobless men, or men with spindly legs – simply nice guys fervently hoping for a cute girlfriend, or who have one already but can feel the hot breath of a rival on their necks.
The danger of looking at things biologically is that it creates an image of the world in which only the richest, most powerful, funniest, smartest or most devastatingly attractive men stand any chance with women. Which seems a dismal prospect if you’re not Mister Big. Is it really the case that unassuming men are inevitably the losers in the fierce battle for women?
To find out, a Scandinavian zoologist cut almost forty centimetres off the tail of the long-tailed widow bird, an African songbird whose tail is absurdly long. He stuck those extra centimetres on other males, who became the most desirable overnight. In another experiment, male swallows had long fake tails glued to them. They found partners ten days sooner, had a second brood with a new female bird eight times as often and were twice as likely to have a bit on the side with a female who was already spoken for. Size matters, then, at least to the swallow and the long-tailed widow bird.
In another study, biologists interfered with three groups of swallows. One group had the prongs of their forked tails clipped, another was provided with extra long swallowtails and the third group of swallows had their tails cut short and then repaired to the normal length (to check that the females were being turned on by the tails themselves rather than by the smell of the glue or by freshly cut edges). Sure enough, the shorter-tailed swallows got the short end of the stick. In their nests sixty per cent of the young were shown to be the milkman’s kids, so to speak, whereas the males with artificially long tails were the least often cheated.
Females are ruthless. If they have any choice, they’ll opt for the largest, toughest, most handsome males. If their partners unexpectedly become less attractive, females are more likely to cheat on them. What makes all this completely unfair is that it’s often ‘married’ males that are most popular with unattached females. In elk, for example, the keeper of a harem, who already has the largest number of females, is in demand among those outside the harem as well. The poor single males do all they can to commend themselves, but they usually come off second-best. Rather than taking up with an eager single, a female prefers a spot of hankie-pankie with a popular hunk who’s not available for a long-term relationship. Frustrating, it seems to me. For single guys.

So females select males for their ‘good genes’. Sometimes they go for symmetry, for strength or bright colours, since those things say something about a male’s underlying health or fitness, but what most females fail to realize is that often such features are mere outward show. In truth all that flashy stuff may say nothing about a male’s real genetic value or survival abilities. In one experiment British researchers took a group of female sand flies and allowed them no choice of sexual partner. Some were forced to copulate with males they would undoubtedly have rejected, while others were able to have it away with particularly popular males. The offspring of the unattractive sand flies were in no respect less healthy or viable than those with the sexiest fathers.
All this swagger comes at a price. The houbara bustard, a generally flightless bird of Africa and the Middle East, throws all it has into its mating dance. Brian Preston of the University of Dijon tested the virility of houbara males by having them mate with the houbara equivalent of a sex doll, a fake female with a vessel for collecting sperm. Preston discovered that the males devoting the most time and effort to their mating ritual were the first to show signs of age. Their rate of sperm production dropped far sooner than that of the more laid-back males – something of which women should perhaps be aware.

Another thing women ought to know is this: attractive males invest less in their relationships and families than their less attractive rivals. Swallow females, for example, fall for males that have long tails with lovely, endless forks, but those fine specimens aren’t such devoted fathers as swallows rather less blessed by Mother Nature. One reason may be that females invest more in the offspring of beautiful partners. Research examining various species of bird shows that the females of attractive males lay more eggs, and that their eggs are larger and heavier than those of less handsome chaps. Furthermore, the partners of attractive males are more committed to feeding their progeny, as if they unconsciously want to give the young of prime males an additional push to succeed. With so much effort on the part of his female, the beautiful male can lean back and relax. Hunks are aware of their popularity, so they can allow themselves to be lax in love. ‘Plenty more where you came from’ – that kind of thing.
Something similar seems to go on with people. Research by American psychologist James McNulty and his colleagues suggests that men who are more attractive than their partners give their wives less support when they talk about personal problems than men who are less attractive than their wives. Less handsome men respond with more concern and cooperation when their partners talk about goals such as eating more healthily, getting more exercise or looking for a new job. Women would therefore perhaps do well to choose men who are slightly less attractive than they are.
Sand gobies – small, inconspicuous fish that live in European coastal waters – seem to have figured out that alpha males don’t always make the best partners. The females reject dominant males and choose caring fathers instead.
Yet many women fall for the kind of bluff from which they ultimately have little to gain. They want that sexy man purely because he’s sexy, many evolutionary biologists believe. Back in the 1930s, British evolutionary biologist and statistician Ronald Fisher claimed that women go after men who appeal to other women. In making their choice, in other words, women look at other women’s preferences.
If a guppy is allowed to choose between two males and then sees another female select the rejected male, she’ll change her choice when the test is rerun. She suddenly gets the idea that the nerd who failed to interest her might be nicer than his rival. Anyone who has noticed his ex suddenly want him back once he’s got himself another woman has experienced this mechanism first hand. She decided you were no good any more, but now? ‘If she sees something in him…’
Fisher’s conclusion has been called ‘the hypothesis of the sexy sons’. The evolutionary theory behind it is that when a female gets herself impregnated by a man who is popular with other women, there’s a good chance her sons will be in demand as well, among the next generation of girls. The genes of a woman who falls for men who attract other women have more chance of spreading via her sexy sons than the genes of a mother who falls for a type that’s less in demand.
This hypothesis is supported, at least in part, by research. Genetically, the offspring of sand fly mothers who had sex with an unattractive male were not any less strong or healthy, but girls of their own generation nevertheless passed them over. The sons of the popular males, by contrast, suited the tastes of the next generation too. Perhaps this is what’s going on, unconsciously, in girls who turn giddy at the sight of the most handsome boy in the class and imagine what beautiful children they might be able to have with him. From afar they can already sense the teeny-boppers of the next generation going all weak-kneed over their sons.

Now for some truly good news. Even though women often go for big, sexy, handsome, rich and burly men, it turns out that substandard, less handsome men can compensate for their imperfections and lack of physical strength. In baboon communities, most of the offspring stem from the alpha males, but more of the progeny of others are mixed up with them than you might think.
Some unassuming males are in fact close friends of attractive females, bringing them tasty snacks, helping them care for their young, grooming and cuddling them from time to time and thereby ensuring an attachment is formed. Research by Dutch behavioural biologist Jorg Massen has shown that male macaques, especially in the mating season (which can’t be pure coincidence), invest in their female friendships. Others who are not at the top of the pecking order may join up with fellow lone males. Real masculine friendships emerge and together the friends sometimes manage to distract the strongest males, get the better of them, or impress a female.
Those who lack brawn need brains. This applies to animals as well as humans. And sometimes the smartest approach is to be self-effacing. Among bullfrogs, for example, it’s the dominant males who call out in chorus to attract females. Sure enough, the noisiest among them are favourites with the girls, since the louder the call, the bigger the male and the larger his territory. The young males have no territories, so they are of no interest to the females, yet they don’t do too badly. They save energy by not croaking, and although they don’t pull the girls they don’t alert predators, either, and don’t get injured in fights with other males. A youngster will stay close to an attractive male and hide in the shadows. When a female comes along, on her way to a calling male, he may get a chance to ‘steal’ a moment of sexual intimacy with her.
A ‘satellite’ is what biologists call the kind of clever male who stays near a successful male to improve his own chances. Sometimes satellites may be able to hope for better times. If they can stick around in the vicinity of a burly male for long enough, there’s a chance they may inherit his territory. In an African fish called Astatotilapia burtoni, this kind of transfer of power leads to a remarkable transformation of the satellite male. If he happens to be nearby when one of his domineering brothers is taken by a bird, he instantly experiences a fabulous promotion. His new status as ‘major landowner’ causes a metamorphosis that can only inspire respect, turning him within a few hours from a peace-loving, asexual and colourless character into a lemon yellow or aquamarine alpha male with whopping testicles. His personality assumes grotesque proportions as well. He becomes just as aggressive and hot blooded as he was once modest and courteous.

Sometimes nature has arranged things so that within a single species a number of different types of male exist that pursue the same strategy all their lives. Take the ruff, a large wading bird. The satellite males are a different colour from the territorial males and they offer their services as assistants. They draw females to the mating arena, since girls are aroused by seeing males dancing together. That way the satellites can discreetly take over while the dominant birds are fighting other males, or exhausted. A third type of male, discovered relatively recently, takes a quite different approach. He looks just like a female and behaves like one too. This ‘transvestite’ ruff enters the mating arena undetected, allows himself to be covered by other males and seizes his chance when the others aren’t looking, busy with their own performance.
Biologists call this kind of strategy mimicry, and it can be seen in a number of species whose males are fierce competitors, as if some individuals have decided to try a different tack rather than hazard a trial of strength. In tiger salamanders the female impersonators, known as ‘sneakers’, will wriggle in between male and female during the mating ritual. The male sees his rival as a potential sweetheart and deposits his sperm ampulla on the ground in front of him. The transvestite doesn’t pick up the package but instead lays his own sperm on top, so that the real female takes only his. Clever stuff.

What can we learn from all this? That there is hope. By being smart and attentive, an unassuming male can get a long way in love. Less attractive males have a real chance of a relationship if they show they are hugely loving and caring, and indefatigable nest-builders. Human females seem to realize perfectly well, incidentally, that less dominant males are worth bothering with. A British study shows that women are generally keen on macho men with broad jaws and big noses for brief affairs, but not for long-term relationships. Rightly or wrongly, they regard them as less affectionate and trustworthy, and less likely to form attachments. Men with rather gentler characteristics are more attractive as partners in life.
Women do want sexy men, but sexy doesn’t always have to mean big, handsome and rich. What makes a man sexy is above all the fact that other women find him attractive. Men can make use of that fact. It’s worth investing in female contacts. In America a way has been found of cashing in on the ability of women to attract women. If you’re a shy type of guy, you can engage the services of ‘wing women’, attractive young ladies who tell potential conquests what a nice man you are. Never again will you have to stand there nervously spouting your feeble chat-up line.



Translated by Liz Waters