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BIRDS DO IT, BEES DO IT
Sex in the Animal Kingdom
Sex is often thought of as an animal activity ("You're a tiger!"), and the animal kingdom is as good a place as any to start a comparative sex education. Evolution has thrown up innumerable sexual variations in the living world. Some creatures, like aphids, manage to do without sex at all and reproduce using a cloning process, while others can't seem to get enough of it, the humble single-celled paramecium evolving (somewhat extravagantly) eight sexes rather than the more usual two. Some creatures (many species of reef-living fish, for example) have distinctly shaky sexual identities and will change gender at the drop of a hat. Others like spiders and bristle worms combine sex with cannibalism. Indeed, compared to many animals, the sex lives of the most infamous human libertines seem positively lackluster.
The Naked Ape
As might be expected, when compared with animals, human sex lives most closely resemble those of our nearest relatives--the chimpanzees--rather than gorillas and our more distant cousins the monkeys. Gorillas have tiny penises compared to body size; on average they come in at 1 1"4 inches. Orangutans aren't much bigger at 1 1"2 inches, while the relatively small chimps are a whopping 23Ú4 inches. Humans come out best with an average of 5 1"2 inches, but there seems to be no reason for this relatively huge size; a 2-inch penis would do the job just as well. Gorillas don't need to be well equipped in this respect because a dominant male keeps a harem of females. This means there's very little day-to-day competition with other males. In contrast, chimps live in largegroups where females mate with a number of different males every day. Chimps need a relatively large penis and a high volume of sperm production to compete. The sperm acts as a douche, washing out the sperm left by a female's previous lovers. It's the male chimp who produces the most sperm who will father the most children. This is why chimp testicles weigh around 4 ounces each, while the more monogamous humans clock in at only an ounce and a half.
Proportionally the largest testes in the primate world belong to the woolly spider monkey. Females of the species have been known to mate as many as eleven times a day when in heat and literally overflow with sperm. This excess is treated as a nutritious snack, and spider monkeys lick it up by the mouthful.
Giving Him the Bone
An interesting difference between humans and animals is the lack of a human "penis bone," also known as an os penis. The majority of mammals, including bears, cats, dogs, weasels, moles, shrews, and most primates, possess such a bone, and why humans don't is a mystery. The size of these bones varies. Walruses have os bones two feet long, resembling ivory truncheons, while bats have tiny ones. As a rule, fish lack an os bone (which would spoil their streamlined shape), as do most birds (where they'd be an unnecessary weight).
Some birds have penises; these are usually found among flightless birds (where the extra weight isn't a disadvantage) and aquatic birds like swans, ducks, and geese (where aquatic mating means there's a chance of sperm being washed away). It's probably a coincidence that penis-owning waterfowl seem to be the ones that most commonly indulge in rape. Male ducks have a reputation for this sort of thing and often take part in "gang bangs"--large numbers of drakes mobbing a female for sex and sometimes drowning her as a consequence. Bird penises tend to resemble mammalian penises but do not contain a urethra to drain the bladder. Some can be remarkably long; the Argentine lake duck commonly has an 8-inch penis, but the largest reach 16 inches.
For those who'd like to see one, fresh ostrich penises can be bought over the Internet as an aphrodisiac.
The record for the world's largest penis is held by the world's largest mammal, the blue whale, which has an organ just over ten feet long and one foot in diameter. The sperm whale (named after spermaceti, a mysterious white oily substance found in its head) comes a close second with a nine-footer. A whale's penis is known as a dork, which is where the insult comes from.
Among land mammals, giraffes have erections reaching four feet long, while elephant erections can reach five or six feet. One enterprising biologist has even gone as far as to calculate the average weight of an elephant penis--59.5 pounds (with testicles at 4.4 pounds each). Rhinos tend to be shorter in this department, their penises being around two feet long; however, they make up for it by being prodigious ejaculators, some coming as many as ten times during a half-hour session. These genitals have been put to some unusual uses in the past. In India golf bags have been made from elephant penises, while in Africa rhino and hippo penises were often stretched and dried to make whips.
Smaller animals may be less impressively equipped, but many make up for it by having bizarre penis shapes. Some animals, like marsupial opossums, have two--one for each of the female opossum's paired vaginas.
Pigs have corkscrew-shaped penises; the male pig makes semirotary motions to literally screw himself into his mate. Spider monkeys have barbed penises to help them hang on during mating. Tomcats also have barbed penises; the pain caused by withdrawal is the stimulus that causes the female to release her eggs. Like pigs, some bulls have corkscrew penises, though in this case it's an undesirable medical condition that makes mating difficult.
Insects have unusual penises. For example, dragonflies have shovel-shaped organs designed to scoop any previously deposited rival semen out of a female. One of the most bizarre boners belongs to the European rabbit flea, which has a penis consisting of two coiled rods, with sperm wound around the smaller one like springs. Some earwigs have two penises--they are very brittle and a spare is needed in case the main one breaks off. Male bees (drones) have alarming-looking genitals. Even more alarming is the fact that they explode. Once the drone has mated with a queen bee in flight, his genitals burst with a pop that can be heard some distance away. The explosion blocks the queen's genitals so she can't receive sperm from any other male.
Barnacles have developed a penis to help solve their immobility problem. Once it's glued itself to something solid, a male barnacle is stuck for life; however, its penis is commonly 150 percent longer than its body and is able to snake out and molest any female within striking distance.
We're used to thinking of sperm as numerous and tiny, but many creatures produce a small number of relatively enormous sperm cells. The house centipede produces a sperm cell that is as long as its body (commonly over 4.7 inches), and some beetle species go one better and produce sperm that are longer than their owners, coiling them up like springs inside the body. An unfortunate side effect is that after fertilization the female often has to waddle around with a sperm tail sticking out of her rear end. Proportionally, the record for the longest sperm belongs to the fruit fly, Drosophila bifurca; it has sperm 2.4 inches in length, twenty times longer than its entire body.
Some creatures produce spermatophores, dense packets of sperm coated with protective gels. Octopi use spermatophores that are three feet long and as thin as a pencil. Some octopus spermatophores have barbs to stop them from being withdrawn once they're placed inside the female, a necessary precaution, as unbarbed spermatophores are often removed and eaten. Katydids (relatives of the grasshopper) also make use of sperm as food; here females have to be bribed with sperm food parcels before they'll allow their eggs to be fertilized.
Perverts of the Animal Kingdom
Bedbugs have extremely unsavory sexual habits. Female bedbugs are born without vaginas, so sperm is passed on during an act of "traumatic copulation." The bedbug's penis is a swordlike rod stabbed into the female's body, depositing sperm into her gut. The sperm then travels via the bloodstream to a special storage gland, where it is kept for further use. This system has a benefit for the female, as in hard times she can use this sperm as a free meal. Some African bedbugs play a variation to this game by indulging in "male rape." They stab other males in the hope that, when the attacked male mates with a female, some of their sperm will be passed on as well. To obtain a free sperm meal, some males deliberately invite an attack by disguising themselves as females.
Some bean weevil species are equally repellent, having spine-covered penises that deliberately cripple the female. The lacerations caused by these penises are often fatal: the female lives long enough to lay her eggs but not so long that she has a chance to mate with rival males.
Coming in a close third in the pervert stakes are banana slugs. Slugs are hermaphroditic, and some pairs mate as equals, playing both male and female roles. Others use this moment of intimacy as an opportunity to gnaw off the penis of their sex partner, forcing them to become exclusively female. These penises represent a hearty meal; banana slugs are commonly 5 inches long but may have penises as long as 30 inches.
Another animal with kinky habits is the American slipper snail (Crepidula fornicata). Here a male snail attaches itself to a rock and becomes a female. Another male snail will then settle on the female and mate with her; should a third male land on the second snail, then snail number two will change into a female and be mated with. This might carry on until up to fourteen snails are welded in a tower of lust.
After mating, many male organisms seal up the vaginal canal of their sex partners. Some parasitic worms exude a glue that seals the female's organs shut. Other animals leave fluid deposits that harden to form a plug. It's thought that many animal penises have such odd shapes because they're designed to get around these vaginal plugs. Male rats are said to be particularly effective at this and can dislodge 68 percent of these obstructions. Female moles plug up their own vaginas to prevent earth from getting inside; secretions from various glands mix into a gummy mass that sets like epoxy resin.
HELLO, I LOVE YOU
Just what it is that makes one individual irresistible and intoxicating to another has been a question posed on more than the odd pop song down the years and in more scientific arenas, too. Some people believe there is no overall standard of beauty. They point out that what rates as attractive differs around the world and often changes over time. Standards of beauty will also differ from person to person; as one Japanese saying puts it: "In the eyes of the lover, pockmarks are dimples." Despite these factors many researchers think that sound scientific principles must underlie human attraction, and a number of theories have sprung up to explain just what makes the perfect mate.
You've Got the Cutest Little . . .
One popular theory is that attractive faces are "babyish," with small lips, high foreheads, small chins, and big eyes. The idea is that these faces remind us of children and trigger a protective response. Unfortunately this theory does not take into account the fact that men often cite high cheekbones as being attractive, while women rate a broad jaw as an attractive male feature. Neither of these is a "baby" feature. Added to this is the fact that babies usually have large fleshy cheeks, which have never been rated as attractive in adults. Having a "baby face" is also disadvantageous in that it suggests incompetence--not a desirable feature in a breeding partner. Babies are cute but extremely inept; you wouldn't want one servicing your car.
Another theory is that attractive facial features are ones that indicate a correct hormone balance. A broad jaw is a sign of high testosterone levels, so a broad-jawed man is attractive while a broad-jawed female is less so. A sign of low testosterone in women is a fine head of hair. Testosterone leads to hair loss, so a woman with long silky tresses is unlikely to have much.
Another factor is that the by-products of hormones are often toxic, so the fact that you're good-looking (i.e., have the correct hormonal balance for your sex) and in good health would also suggest that you have an excellent immune system capable of dealing with these poisons.
One theory has been developed to try and explain why people are often attracted to the exotic and unusual. In these cases it's thought that people are seeking out "rare genes." The idea is that in any population parasites have evolved to take advantage of the "average" person. If you can produce nonaverage children by having sex with someone with nonaverage genes, then your children will be better able to resist parasites. According to the theory, this is why blondes have more fun. Natural blond hair is not common in most societies, so it represents a rare genotype.
Symmetry Is Sexy
Symmetry has also been cited as a factor in attractiveness. If you take a portrait, split it down the middle, and match each half with its mirror image, you get two perfectly symmetrical faces. Usually both symmetrical faces are more attractive than the original. It's not known why a symmetrical face is more attractive than a lopsided one. Perhaps the more regular your features, the better the genes you're carrying. Many famously good-looking people (Tom Cruise, for example) have a high level of facial symmetry.
Human brains seem to like storing information as simple models. When we're young, we build up a model of an "average" face in our minds, based on the faces we see around us every day. If we come across a new face, we compare it to the average and add some distinguishing features to tell it apart from all the others buried in our memory. It's been discovered that "average" faces (created on computers by overlaying multiple portraits) are usually rated as being highly attractive. The theory is that we find familiar people attractive, and the computer's average face will often closely match the average, attractive face we carry in our memory.
The theory of averageness seems to be borne out by the fact that many people marry someone who resembles one of their parents. This isn't the result of psychological Oedipus and Elektra complexes; rather their average, attractive face will be based on the faces they saw most often as children--their parents. Since most children resemble their parents, this is also why many people choose a partner who resembles themselves.