Zoobiquity (13 page)

We’ve inherited a complex sexual heritage from our animal ancestors. The broad range of human sexual interests and practices attests to this. But we humans are also able to project the consequences of our actions. For better or worse, we live in cultures that have rules and taboos. Our sexual behavior cannot be divorced from that, and it’s a mistake to look to “nature” for moral guidance. In the words of Marlene Zuk: “
Using information about animal behavior to justify social or political ideology is wrong.… People need to be able to make decisions about their lives without worrying about keeping up with the bonobos.”

Some sexual practices so repel us as human beings that we consider them immoral and have made them illegal: rape, pedophilia, incest, necrophilia, bestiality. But millions of times a day, millions of animals engage in them.
Normal reproduction for species of insects, scorpions, ducks, and apes requires an act of rape (often called “coercive copulation” by biologists).
New York City’s bedbug epidemic has made it common knowledge that bedbugs (and their relatives) mate through a technique called “traumatic” or “hypodermic” insemination, in which the male mounts a female, stabs her with his scimitar-sharp male organ, and ejaculates directly into her bloodstream.
An animal form of necrophilia can be found in creatures from frogs to mallard ducks, which have been observed copulating with dead members of their own species.
Sex with relatives and immature members of the group occurs in primates and many other vertebrate and invertebrate species; some evolutionary biologists think that the parent-child clashes we associate with adolescence may have emerged to protect newly sexualized animals from early mating attempts by their own relatives.

And interspecies sex—known as bestiality when humans engage in it—has been occurring for an extremely long time, possibly as long as sex itself has been going on. Respectable scientific studies theorize that sex between different species actually serves the evolutionary purpose of creating new variations. Birkhead notes, “
Breeding males are usually highly motivated and often indiscriminate. Ejaculation carries little cost
and there has therefore probably been little selection against males copulating with the wrong species. Indeed, selection may have favoured a lack of discrimination among males, since he who hesitates is lost.”

But while there are lines between what humans can and should do sexually, there is an important human takeaway from the study of manatee oral sex, or bighorn sheep anal intercourse, or bat cunnilingus. What every one of these sexual behaviors—from stallion masturbation to monkey fellatio to frog necrophilia—reminds us is that sex is not always linked to reproduction. In fact, it could be argued that the vast majority of sexual activity in animals does not have procreation as its goal.

Marlene Zuk agrees: “
Even in nonhumans, sex can be about more than reproduction … Even sex is not always about sex, at least in the short term,” she writes. Anders Ågmo, a behavioral neuroscientist, takes it a step further. He has called the production of offspring “
an accidental physiological side effect of sex behavior.”

For animals, sex provides benefits besides reproduction. And the same is true for us. In social mammals, sex promotes bonding between individuals and strengthens relationships. And the repetitive touching, stroking, or hugging that may accompany sex provides some of grooming’s well-known soothing benefits.

Social bonding. Relationship building. Soothing. Are we missing anything? What about pleasure? The pursuit of pleasure may underlie many animals’ interest in sex. But if pleasure is an important driver of sexual activity, then pity the 25 percent of women who claim to derive no enjoyment from it at all. The search for ways to help them brings us to another crossroads of human and veterinary medicine.

While Lancelot, the horse at U.C. Davis, was in the barn struggling with the phantom, about a dozen female horses were outside in a special corral called the mare hotel. This equine inn was less like the Four Seasons and more like Nevada’s infamous Mustang Ranch. Here the mares were getting teased. If you’re like me, a city girl who had little more than a goldfish growing up, mare teasing is a jaw-dropping sight.

A handler led a stallion toward the corral of mares. One by one, he paused the male horse in front of a female. Some mares responded instantly. Their tails shot up, revealing glistening, engorged labia. They
released a hot gush of urine. They shoved their hindquarters toward the stallion. Some swayed their backs in a slightly crouched position, as though inviting the male to mount them. Others displayed what Cornell veterinarian and animal behavior expert Katherine Houpt calls “
the mating face”—“in which the [mare’s] ears are swiveled back and her lips hang loose.”

Other females, however, glanced up at the stallion and went right back to munching their hay. Some took one look and lunged toward the male with flattened ears, showing their teeth and whinnying threateningly.

The different behaviors depended on whether the mares were about to ovulate. Those who responded to the sexually available stallion with pre-copulatory behaviors were either ovulating or just about to. They were, the handler told me, “receptive.” Those who ignored or pushed the male away were “nonreceptive.”

Human women don’t, thank goodness, raise our tails and urinate when a man glances our way on or around day fourteen of our cycles.
We’re said to have what’s called “concealed” ovulation, meaning we lack the obvious “advertisements” of ovulatory status. But evolutionary scholars, like UCLA’s Martie Haselton, are starting to take a closer look at clues we do give off—some of which are less subtle than we might think.
Women have been found to dress more provocatively and roam farther from home when they’re ovulating.
Men perceive ovulating women to be more attractive; strippers get higher tips during the most fertile parts of their cycles.
College-aged women phoned their fathers significantly less often during ovulation than at other times of their cycles—a behavior hypothesized to be some ancient defense mechanism against intrafamily attraction. But even when human females aren’t ovulating, they may seek the pleasures of sex and orgasm.

Physically, female orgasm is very similar to male orgasm. Parasympathetic buildup abruptly shifts into a sympathetic burst of muscle contractions that end with a flood of rewarding neurochemicals and brain-wave changes. The sensory and physical similarity of orgasm across genders arises from nearly identical networks of nerves and hormones.
In developing fetuses, male and female genitals spring from the same primordial cells. Indeed, the embryos of many species—whether human or canine or crocodilian—begin with no specific gender. Influences such as hormones, temperature, and environmental effects lead to the development
of a penis in males but suppress its growth in females. In other words, a wife’s labia and her husband’s scrotum were once embryonically identical, as were her clitoris and the glans and upper shaft of his penis.

A quick comparative survey of animal sexuality reveals that the clitoris is not a uniquely human organ. This “tender button” has been found in a huge variety of female creatures, including horses, small rodents, a wide variety of primates, raccoons, walruses, seals, bears, and pigs. Bonobo clitorises and labia can swell to the size of soccer balls. Thanks to high circulating testosterone, the African spotted hyena sports a clitoris so large it’s called a pseudopenis. Clitoris licking in these fiercely matriarchal societies is a sign of submission. Oversized clitorises are shared by European moles, some lemurs, monkeys, and a Southeast Asian carnivore called a binturong.

Significantly, all these animal clitorises—just like animal penises—are densely packed with nerve endings. This means the suite of sensations that makes up an orgasm may be shared as well across genders and species.

And yet, even with the physical ability to feel orgasms, many women don’t.
An estimated 40 percent of all women worldwide have sexual complaints. These include dyspareunia (generalized pain during sexual activity) and vaginismus (a rare affliction in which the muscles of the vagina clamp painfully and uncontrollably shut, prohibiting penile entry).

But by far the most common female sexual dysfunctions are low desire, impaired arousal, sexual aversion, inhibition, and inorgasmia. These conditions—sometimes collectively called hypoactive sexual desire disorder (HSDD)—can be persistent and distressing.
They affect as many as one-fourth of all women worldwide. In the United States, although estimates vary, some 20 percent of women are thought to have HSDD. This suggests that every year more women suffer from low desire and failure to orgasm than are diagnosed with breast cancer, heart attacks, osteoporosis, and kidney stones
combined
. Like male erectile and ejaculatory dysfunction, female hyposexuality is not, on its own, life threatening. But it can create severe quality-of-life challenges that, in turn, can carry serious health risks, such as depression.

Low desire and HSDD can be situational (directed toward one partner) or general (a lack of interest in all sex). The patient may complain
of other symptoms, including depression, anxiety, conflict, fatigue, and stress. Her detachment can range from dull, “close your eyes and think of England” resignation to actively finding sex distasteful or repulsive. Phobic and panic responses can occur at this extreme end of the disorder. Some women feel a physical urge to push away their partner. Some may feel like kicking, biting, hitting, or verbally lashing out.

Doctors treat HSDD with psychotherapy and by prescribing testosterone supplements, which can boost sex drive not just in men but in women as well. These interventions are, however, usually only moderately successful. Testosterone lacks FDA approval for treating HSDD (it must be prescribed “off-label”), and studies suggest that the time a woman spends on her therapist’s couch does little to improve the quality of the time she spends with her mate on a mattress. Patients may be instructed to stop taking certain medications, particularly the selective serotonin reuptake inhibitor (SSRI) antidepressants, such as Prozac, Paxil, and Zoloft, because they can dull the libido. Beyond these basic fixes, however, HSDD’s treatment outlook is somewhat gloomy. One online medical encyclopedia warns, “
Cases of dissatisfaction by both partners often do not respond to such therapy, and frequently culminate in separation, finding a new sexual partner, and divorce.”

I asked Dr. Janet Roser what she would prescribe if she noticed a female avoiding male sexual attention, ignoring solicitations, even lashing out at an unwanted advance. She said, “Nothing—if the patient is not in heat.” Roser is a neuroendocrinologist who treats the horses at the U.C. Davis barn. For her, hearing about waning sexual interest leads immediately to this assumption: the female is not in estrus. She is nonreceptive. And being nonreceptive is a perfectly normal—indeed, expected—state for a female animal when she is not nearing ovulation.

As I’d seen at the horse barn when the handlers teased the mares, nonreceptive female horses may whinny, bite, and lunge or kick at approaching stallions. Many other female animals have equally obvious ways of making it clear to advancing males that they are not interested in sex.
Female rats scratch, bite, and vocalize. Female cats hiss or strike out with their claws. Female macaques gang up on approaching males. Female llamas spit at their pursuers and run away from them, while female vampire bats lunge threateningly with their infamous canine teeth exposed. Nonreceptive female butterflies twist their abdomens upward and away
from incoming males. Female fruit flies display the same behavior; some may even kick a pursuing male. Some beetles have sliding plates made of chitin they can position across their vaginal openings to deflect unwanted penetration.

There are several scenarios in which nonhuman females have sex when they’re not fertile or receptive.
Entomologists Randy Thornhill and John Alcock have described a phenomenon they call “convenience polyandry” in which a female will accept (or endure) the advances of a particularly aggressive or persistent male just to get him to leave her alone. And it’s interesting to observe differences in receptive behavior between natural settings and captivity.
James Pfaus, a Concordia University psychologist who studies the neurobiology of sexual behavior, told me that a female macaque housed with one male will copulate daily with him. When she’s in estrus, she accepts more frequent liaisons, sometimes two or three per day. However, when she’s returned to a more natural macaque social group—in which breeding females band together and solicit sex from males only on the days they’re fertile—she copulates only around ovulation. Coercive copulation or rape is another scenario in which females have sex during their nonreceptive phases, although it must be said that males of many species do respect females’ nonreceptive signals. If a female tells him to back off, some males will seek sex elsewhere—usually from another willing female but, in some species at certain times of the year, from another male.

Unenthusiastic acceptance of sex. Avoidance of it if possible. Occasional outright hostility or violence toward the interested male partner. When we put animal nonreceptivity side by side with female hypoactive sexual desire disorder, it’s possible to see some intriguing crossovers. I suspect that low desire as a diagnosis is so high simply because women expect to be receptive to sex 24/7, regardless of where we are in our cycles. Although sexual response can occur during days outside of our windows of ovulation, in fact, women are fertile for only three to five days during each month. This may make women less receptive at other times.

Receptivity in animals is guided by surges in female sex hormones. These hormones, working through complex neural pathways in the spinal cord and brain, can cause certain predictable mating behaviors and even body postures. One stance in particular is a dead giveaway that a female is receptive. Ranchers, biologists, breeders, and veterinarians
will recognize it. It’s called lordosis.
Lordosis is a very specific, hormonally driven posture in which the female arches her lower spine into a swayback, with her buttocks tipped rearward. Her pelvis softens and stretches. If she has a tail, during lordosis she might raise it or hold it to one side, exposing her genitals. Horses, cats, and rats have an exaggerated lordotic response, but it’s also seen in sows, guinea pigs, and some primates.
According to Donald Pfaff, an expert on lordosis based at Rockefeller University, it’s a widespread neurochemical response seen in all quadruped females. Basically, he writes, a nerve signal triggered by the touch of a mounting male “
ascend[s] the spinal cord of the female to reach her hindbrain and then her midbrain. There nerve cells receive a sex-hormone-influenced signal from the ventromedial hypothalamus. If the female has received adequate doses of estrogens and progesterone, that signal from the hypothalamus says ‘Go, Mate, Do Lordosis Behavior.’ If not, the signal is ‘Resist, Kick, Flee the Male.’ ”