A recent study of people who had near-death experiences (NDEs) found that those people were more likely to have had incidents where dreaming and wakefulness intertwined to some degree. I’ve had exactly that kind of “waking dream” experience myself, and I’ve found it to be a most unpleasant state. Despite—or maybe because—it’s such an uncomfortable occurrence, I’m very curious about what’s going on, so I’ve read a little bit about it. I learned that what happens is that for some reason you’re partly asleep (having dreams and unable to move due to the muscle paralysis that accompanies some stages of sleep) but also partly awake (which makes the dreams more like hallucinations, and the feeling of paralysis recognizable and, to me, terrifying). Because people who had NDEs were more likely to also have had this kind of odd sleep/waking experience, researchers want to figure out more about what is going on in the brain to trigger these experiences.

http://www.nature.com/news/2006/060410/full/060410-2.html

Hypnagogic hallucinations are the kind of wakeful dreams that you have as you’re falling asleep, and hypnopompic hallucinations happen as you’re awakening. I mostly have the former; they happen about an hour after I go to sleep. (I think there is a transition to a different type of sleep somewhere around an hour into the night, and maybe I sometimes don’t navigate the transition well.) This Wikipedia article mentions that creative types use the hypnagogic state to tap into their creativity, and I’d love to be able to experience it that way rather than as an unpleasant time when things happen that scare the bejabbers out of me. The Wikipedia article also mentions a possible connection with temporal lobe epilepsy, which I think is associated with both creativity and a tendency toward strong religious experiences. Hypnagogic hallucinations might explain why some people believe that they’ve seen religious apparitions or encountered aliens at night.

The degree of biodiversity on Earth goes through cyclic decreases about every 62 million years; this has been going on for at least 542 million years. Recent research links this periodic decrease in species with the movement of the solar system through the galaxy. As the solar system orbits the center of the galaxy, it also moves up and down through the plane of the galaxy. More species die off when the Earth is most exposed to cosmic rays from outside the galaxy, at the high point of the solar system’s upward movement, which takes it above the galactic plane. Life is a chancy thing.

http://www.newscientist.com/article/dn8923–life-waxes-and-wanes-with-bobbing-of-the-solar-system.html

When I think of ways that we deal with being thinking meat, I think of things like music or books or art, or love. But psychoactive plant-derived substances also have their place. Chocolate is one of the better sources in my opinion, although plenty of people swear instead by coffee or wine or marijuana or even tea.

On Christmas Eve my older son placed a gift bag full of chocolate under the Christmas tree for me. There were nine large bars in the bag, ranging in cacao content from 70% to an astounding 87%. The labels bore mysterious words like “Sao Thome”, “single origin”, “cocoa nibs”, and “criollo”. In addition to the joys of tasting the chocolate, which I am still savoring, I’m discovering the joys of learning chocolate lingo and lore.

I’ve been fond of chocolate for as long as I can remember, but when I was a child my tastes did not extend much beyond Hershey’s, and my chocolate sophistication grew only slowly. I realized that I preferred dark to light, and eventually found sources for good dark bars; the Chocolove brand has dark bars that range from 55% cacao content to 77% (plus you get a love poem inside the wrapper). Other than those variations, I was aware only of differences in the fruits and nuts added to the bars: almonds, cherries, raspberries, ginger.

After I was introduced to this rich variety of dark chocolate bars from Greg, I spent a little time exploring Sahara Mart, the store where he had bought them. I had never seen anything like it. The variety was so great that I actually felt baffled by the range of choices, and I’ve never felt unsure of myself when shopping for chocolate before. I was intrigued by the labels, and wondered how you would know whether you wanted Belgian chocolate or South American chocolate, and what made a bar made with Venezuelan beans into a European chocolate. There is obviously a great deal to be learned here.

Coffee and chocolate are relatively recent additions to the European arsenal of everyday psychoactive chemicals, and the vocabulary for both appears to have been borrowed from that used for wine. My friend Barb sent me some dark chocolate from France for Christmas, a stack of luscious dark tissue-wrapped squares each from a different locale (Ecuador, Madagascar, Sao Thome, Vanuatu…). Each type has a descriptive blurb with language reminiscent of that used to describe wines, with references to fruit or spice or tobacco, and jargon like “long on the palate” or “powerful nose”. One of the chocolate bars that Greg gave me had instructions written on the wrapper for how to taste good chocolate, which reminded me of the advice for tasting wine (although you cannot admire the glossy shine of the wine or run your thumb over it to release the aroma). Coffee is also described sometimes in the lyrical metaphors used for wine, and I’ve seen coffee ratings that assign numerical scores for qualities like body, acidity, flavor, aftertaste, and something labeled “roast (agtron)”. Evidently there is a rich coffee lore to be learned as well.

Curiously, one of the things that these essential luxuries have in common is the sort of link to a particular environment that is summed up in the word “terroir”. Terroir describes the way that geography and climate and weather and soil affect the taste of the coffee or tea or chocolate or wine. The sunlight, soil chemistry, moisture, humidity, and temperature of each area will nurture a particular taste, and even that will vary from year to year. For wine and chocolate, the term “varietal” or “select origin” is related to where the grapes or beans come from, although I’ve had a hard time pinning down exactly what it means to the chocolate world; the size of the region involved can be as small as a particular plantation or as large as a country.

At Sahara Mart, you can find chocolate bars from the same company, with the same cacao content, that differ only in the country of origin. (I wonder if I will ever be able to identify the origin of a chocolate bar by taste.) I used to send good coffee to one of my brothers, who for awhile carried his passion for coffee to such lengths that he was roasting his own beans. I don’t drink coffee, so the names didn’t tell me much about the qualities of the coffee, but I was enchanted by them anyway, redolent as they were of tropical locales. Certainly the tropical origins and the history of chocolate add to its romance. The cocoa tree, Theobroma cacao, grows only within 20 degrees of the equator at lower elevations. The name “theobroma” comes from the Greek words that mean “food of the gods”. This is one of the facts I relish about chocolate. Others may sing the praises of their everyday drug of choice, but chocolate is the only one, as far as I know, that claims with its very name that it’s the chosen nourishment of deities.

But of course it’s not just the romance of place that makes these essential luxuries so compelling. They all have some kind of physiological and psychological effects, due to their chemical makeup. Chocolate doesn’t give you a buzz or make you go zoom, but it does seem to make people happy. On stressful days or during long meetings at work, one of my bosses passes around some chocolate to relieve the stress. It’s amazing, when you stop to think about it, how substances that contribute so much to our lives require such extensive processing to get them to their optimum state. Actually coffee and cacao need to be processed in order to even be fit for human consumption, because the untreated seeds are so bitter.

I can understand how someone might have discovered by happy accident that grapes ferment and realized that unlike many other fermented products, they are enhanced rather than spoiled by the process. Winemaking could take off from there easily enough. But it’s surprising that anyone thought to roast and grind cocoa beans up, much less put chocolate through the complex process it requires to go from pod to Godiva. The bitter seeds are surrounded by a sweet sticky substance; the bean pods don’t break open by themselves, and so the tree relies on animals to break open the pods for the sweet reward inside. The bitter seeds offer no temptation to nibblers, so they are discarded wherever the animal drops them when it’s done with the sweet stuff, and the tree gets its seed dispersed and thus, in the manner of all living things, it works to ensure that its kind continue upon the Earth.

That’s straightforward enough. But then someone thought to process the seeds so that they are edible. This involves fermenting, drying, roasting, and winnowing (winnowing removes the husks of the shell). (Cocoa nibs, by the way, are the shelled, degermed beans. They add a pleasant crunch to a bar of dark chocolate.) After the beans have been subjected to all of this, they are then ground to make a product called “mass” which is the basis for a number of chocolate goodies. Dried, it becomes cocoa powder; with the addition of sugar and possibly milk, and further processing, it becomes chocolate. Once chocolate becomes tempting to eat, the alkaloids that make the beans bitter become important for their amazing effects on some animals.

There’s nothing particularly mysterious about plants containing things that are useful to humans. Plants and humans have co-evolved; we have adapted to the foods available where our ancestors came from. For a good introduction to the co-evolution of humans and their food, read Gary Paul Nabhan’s Why Some Like It Hot: Food, Genes, and Cultural Diversity. He describes things like the relationship between fava beans and malaria or lactose intolerance and climate, and also explains why a move away from a traditional diet can be so devastating to the health. Plants naturally produce chemicals that slot into human biochemistry one way or another; that’s how natural herbal remedies work (to the degree that they work at all, of course). Over time, humans apply selection pressure to cultivate the types of plants that help them the most, breeding for certain characteristics.

Some of the reputed health benefits of chocolate, especially dark chocolate with less sugar, are due to the presence of flavonols, antioxidants, and trace elements similar to those that make other fruits and vegetables so good for us. Chocolate contains phenols that might promote cardiovascular health, for example, and the trace mineral magnesium. (There is some speculation that the magnesium might be the reason that premenstrual women often crave chocolate.)

But more mysterious and magical than the contributions to cardiovascular health, as welcome as those may be, are the chemicals that mesh with our own brain chemistry in pleasant ways. Coffee, tea, chocolate, and marijuana are different from alcohol in that they have their effects on us through alkaloids that interact with an existing chemical network in our brains; their chemistry unlocks doors in our brain for which we also have endogenous chemical keys. Alcohol tinkers with the brain surely enough, but it doesn’t contain chemicals that match so amazingly to our existing receptors.

Alkaloids are organic molecules that are usually derivatives of amino acids. Often bitter-tasting and frequently toxic, alkaloids have evolved in plants to discourage animals from eating them, or to encourage only certain animals to eat them. Nicotine and caffeine, although tolerated in certain doses by humans, can fairly be described as toxins. Theobromine, the active ingredient in chocolate, is also toxic for some animals (most famously dogs, when they consume it at high doses). But through the magic of roasting or drying or other types of processing, beans that are loaded with these toxins become some of the greatest delicacies for us humans.

Caffeine and theobromine belong to a class of alkaloids called methylxanthines. Both occur in coffee, tea, and chocolate. In chocolate, there is far more theobromine than caffeine. Like its cousin caffeine, theobromine is a central nervous system stimulant (although much milder in its effects than caffeine); theobromine is also a diuretic and a vasodilator, meaning that it dilates blood vessels (by relaxing their walls). As a hypertensive, I was very interested to learn this, although chocolate also contains phenylethylamine, which is related to the amphetamines and raises blood glucose and blood pressure. According to a recent study, dark chocolate does have the overall effect of lowering blood pressure.

The caveat on any study about the health benefits of chocolate is that the sugar and fat content are generally high. Cocoa butter has a high stearate content, and stearates melt at body temperature, which is part of what gives chocolate its luscious texture. The sugar also probably provides part of the chocolate thrill, although it certainly seems to me that there is much more going on than that, because other sweet treats don’t come anywhere close to being as satisfying as chocolate. At any rate, chocolate is never going to play a major role in a healthful diet. Moderation is in order, and keep in mind that the darker the chocolate, the more health-enhancing substances it contains.

No one knows exactly what the body’s cannabinoid network does.
Several of the chemicals in chocolate play a role in the brain’s chemistry. For example, chocolate contains some serotonin, which is known to be important in regulating mood. Something in high-fat chocolate foods might prompt the brain to produce endorphins, the brain’s own endogenous opiates. Chocolate also contains two compounds that are chemically related to a substance the brain produces, anandamide. The name comes from the Sanskrit word for bliss, and anandamide is the body’s own home-grown analog for THC, the active ingredient in marijuana. Humans have receptors for it not only in the brain but throughout the body. These chemical relatives of anandamide may affect the anandamide receptors directly, or possibly affect the way we react to the body’s own anandamide, enhancing or prolonging its effects by slowing the rate at which this normally short-lived chemical is absorbed.

The reason we have receptors that work with plant-derived stimulants like caffeine and theobromine is not that our receptor systems co-evolved with the plants that produced these substances; we’ve been cultivating these plants for too short a time. They work on us in the way they do because the body has its own stimulant system, the famous fight-or-flight response powered by the adrenals; these stimulants mimic the action of our own biochemistry. It’s a similar story for plant-derived opiates; we have opiate receptors not because we’ve adapted to use these substances from plants, but because our bodies produce their own opiates (endorphins, whose name comes from the words “endogenous morphine”). The plant substances slot into an already existing system in the body, this one also designed to help us deal with stressful situations.

No one knows exactly what the body’s cannabinoid network does. (It’s not even clear what plant-based THC does for the plant; possibilities include protection from potentially damaging ultraviolet radiation, defense against pests—addling them rather than killing them—or perhaps even antibiotic properties.) Endogenous cannabinoids may play a role in seizure frequency in epileptics; they may foster neurogenesis (the growth of new neurons) and help protect the brain from the effects of strokes.

The endogenous cannabinoid system is also important in learning and memory as well as pain relief. Michael Pollan has written about the possible functions of this network in The Botany of Desire: A Plant’s-Eye View of the World, Pollan cites the ideas of Raphael Mechoulam, the first to identify and synthesize THC, who speculates that in addition to its other functions, it may help regulate the processing of emotion. Allyn Howlett, who discovered THC receptors in mouse neurons, suggests that its usefulness in pain relief and the blurring of memory might make it, as Pollan puts it, “the brain’s own drug for coping with the human condition”.

One of the more noteworthy effects of THC and our endogenous cannabinoids is short-term memory loss. Pollan suggests that perhaps in addition to the brain systems devoted to the task of remembering, we also need a system for forgetting. Our minds and bodies are overwhelmed by incoming data, and if we remembered every single bit of it, we’d never be able to find the most important bits. We generalize, we condense multiple similar experiences in our memories, and we forget. This removes some of the enchantment from the world, because we ignore things that we’re familiar with, but it also makes it a manageable place. By interfering with our memory, perhaps marijuana re-enchants the world by allowing us to forget that we’ve gotten jaded by constant contact with the things of everyday life. Forgetting is a key to mindfulness and living in the timeless now. Might some of the chemicals in chocolate do the same thing, in a more subtle way, by allowing anandamide to circulate longer?

Chocolate contains around 300 known chemicals. Perhaps the anandamide relatives, combined with the pleasant stimulation of the theobromine, the sweetness and smoothness of the sugar and fat, and other neurochemicals like serotonin, provide us with just a taste of bliss, not enough to keep us from functioning more or less normally, but enough to make us feel good. The combination of ingredients makes chocolate a potent treat. If the brain reacts to chocolate in part through a brain system for forgetting that helps to us to rediscover the magic of the everyday, that makes it even more deserving of the name “food of the gods.”

The other day I went with a friend to Sahara Mart; he had never seen their chocolate section. We browsed contentedly up and down the display, studying the labels. I picked out some chocolate for another friend (I’ve still got plenty of Christmas chocolate at home to enjoy); he selected a couple of bars to take home with him. We both made mental notes about the kinds we’d like to try some day. As we prepared to leave, we took one last look at our haul and scanned the shelves with satisfaction, contemplating the chocolate awaiting us.

“Doesn’t it make you feel better about life?” I asked.

“Yes, it does,” he said.

Daniel Dennett is visiting Indiana University this week; I’ve heard him give two talks so far, and there’s one more on Thursday. Dennett is a philosopher of mind at Tufts who has written about evolution, consciousness, free will, and most recently about the study of religion as a natural phenomenon. He writes on topics that are central to the idea of humans as thinking meat, namely, naturalistic explanations of how our minds work. Until yesterday I had not heard him speak so I didn’t know that in addition to being a brilliant writer he’s also a very entertaining speaker. Yesterday he talked about consciousness and tonight about free will. I’m not going to try to summarize either talk, because both of the talks and the discussions after each were extraordinarily rich in ideas. But here are a few of the things that stuck in my mind:

When talking about what an ideal theory of consciousness would look like, he said it would be like walking into a deserted factory, everything chugging away and all the work going on, but not a person in sight. I can see why it might be a disconcerting image, but I like it. It’s obvious to anyone who pays attention that we don’t have anything like the whole picture of what’s going on in our brains, and I can live with the idea that the experience of being conscious is an intriguing and complex property arising out of the way the mental machinery runs (and that there’s nothing particularly mysterious that needs a supernatural explanation). Dennett quoted with relish a detractor who said he claimed not that the emperor had no clothes, but that the clothes had no emperor; that’s actually a pretty good way to put it.

Dennett used the concept of magic and various nifty visual illusions to discuss the nature of reality as it relates to consciousness. This is I believe a direct quote from his last slide: The “magic of consciousness”, like stage magic, defies explanation only so long as we take it at face value. Once we appreciate all the non-mysterious ways in which the brain can create benign “user illusions”, we can begin to imagine how the brain creates consciousness.

He spoke of free will as arising out of the “evolution of evitability” (evitability being the degree to which events can be avoided). Evitability is increasing in the world, and our evolved competencies give us moral agency and responsibility even though absolute free will isn’t possible and isn’t worth wanting. As an example of the increase in evitabiilty, he spoke of how we could conceivably avert an asteroid strike, given sufficient warning; “The planet after three billion years has grown a nervous system, and we’re it.” As a beautiful description of the increase of evitability, he offered the following quote from Paul MacCready: “Over billions of years, on a unique sphere, chance has painted a thin covering of life—complex, improbable, wonderful, and fragile. Suddenly we humans, (a recently arrived species no longer subject to the checks and balances inherent in nature), have grown in population, technology, and intelligence to a position of terrible power: we now wield the paintbrush.”

These are just a very small selection of highlights; if you want to learn more, you need to read the books. This evening Dennett recommended the following to someone who hadn’t read any of his books yet: start with Darwin’s Dangerous Idea: Evolution and the Meanings of Life, then read Freedom Evolves, then Consciousness Explained (which he said is his most difficult book), and finally his latest, Breaking the Spell.

This essay from the New York Times by William Broad makes a case (in my opinion a weak one) for why science and religion need not struggle against each other; the essence of his argument is that science and religion inhabit separate spheres and if scientists would show some humility and not expect to explain everything in naturalistic terms, science and religion could peacefully co-exist. (Since I set great store by our ability to explain things in naturalistic terms, I found this essay extremely irritating.) Science and religion are distinctly different kinds of endeavors, so in that sense they are non-overlapping. But there is plenty of overlap in the subject matter they cover (the origins of the earth and the universe, the origins of humankind, and increasingly the reasons for emotions and behavior). And that is where many of the problems lie.

Broad takes as an example the discovery that the prophecies of the ancient Oracle of Delphi were fueled by a mix of intoxicating gases arising through geological processes to the temple where the oracle presided. While explaining the trance states the oracle entered, these scientists declined to discuss the meaning of her utterances or why people set such store by them. I don’t know what field these scientists were in, but they sound like geologists to me, and since the brain science behind how humans use language to create and find cultural meaning is in its infancy if that, I can understand why geologists would not want to speculate in that area. (Actually the “seeming reliability of her pronouncements” can probably be understood in terms of people remembering and maybe writing down the good ones and forgetting the bad ones, or possibly interpreting them after the fact the way people do with Nostradamus.) In other words, just because one branch of science can’t explain everything right now about a phenomenon, that doesn’t mean that the not-yet-understood bits have to be left to religion to explain.

Furthermore, this story about the Oracle of Delphi doesn’t touch on any of the things that exercise religious fundamentalists today. Few people care all that much about how the oracle inspired Socrates, and I’d bet that no one’s religious identity relies on any of her words or their supposedly divine inspiration. This is not a very realistic test for the ability of religious fundamentalists to accept science’s findings about something that matters to them, like for example the origins of humankind. And if it had been, say, the Sermon on the Mount or the Ten Commandments that had been found to be inspired by subterranean intoxicating gases percolating up through a fault system, if scientists had studied just that and nothing about the enduring meaning that people have found in these things, the protests would likely range from cries of “Reductionism!” to cries of “Blasphemy!”

A long-term study of 127 people has yielded some insight into the genetic and situational factors that contribute to depression. Researchers analyzed the participants’ DNA and followed up with them every five years to ask about major life events and depression. The DNA analysis allowed them to identify three different populations: people who are genetically prone to depression, those who are genetically resistant, and those whose DNA represents a mix of both types. When there are enough negative events in a person’s life within a one-year period, those who are genetically liable to depression are much more likely to become depressed than those who are genetically resistant. But even for the genetically vulnerable population, it’s not just a single bad thing happening that can trigger depression, but multiple negative events within a certain time period. Research into the subtleties of genetic and social factors in depression seems like it’s bound to yield better treatments and maybe even ways to help prevent depression. Based on my own experiences with depression, it’s not a simple matter to sort out all the factors that go into a particular depressive episode or even into a tendency toward depression, and one size certainly does not fit all, so this strikes me as very interesting work.

http://www.eurekalert.org/pub_releases/2006-03/uons-nna030106.php

I just returned from the world premiere of an opera based on Thornton Wilder’s play Our Town. With music by Ned Rorem and a libretto by J.D. McClatchy, this opera is lovely, emotionally moving, and I thought very true to the spirit of the play. I’ve always been fascinated by the relationship between different art forms: how they are similar, where they differ, and how they are related to each other. I was impressed and intrigued by the way the libretto distilled the essence of the play; even though some scenes and characters were cut, the elements that gave such meaning to the story were all there. The music was gorgeous; in the last act in particular, I thought that the way the dead sang was somehow what they really would sound like, if they could sing and we could hear them. The whole experience captured very well the core emotions and experiences of the play, which to my mind is an excellent expression of what it means to be thinking meat. It was very satisfying to see the play transmuted so well into another art form. Afterward someone, I think McClatchy, said something to the effect that at the heart of the play was the emotions in Emily’s heart, and if the creators and cast and crew had transmitted those emotions to us so that we experienced them too, then they had done their jobs. That struck me as a pretty good description of one of the roles of art.

This afternoon I heard Ronald Green, an ethicist from Dartmouth, give the 2006 Sims Lecture for the Poynter Center on the IU Bloomington campus. His topic was “Babies by Design? The Ethics of Gene Enhancement.” It was a good lecture, hitting most of the interesting questions regarding the possibility that at some point in the future, humans are going to be able to tinker with their own genetic makeup or even their own evolution. The most interesting area of discussion, and what I’m mostly focusing on below, is the area of germline changes (i.e., changes that affect not just the person receiving the treatment but his or her offspring), and in particular those that are aimed more at enhancing life rather than removing disease.

One of the questions afterward had to do with evolution, and what it would mean to take the “natural” out of natural selection. Green responded with a couple of points; for starters, we evolved for a different landscape from the one we’re in so perhaps it makes sense to adjust our genome to better suit our current environment. For example, we have in some sense adapted to food scarcity, so that abundance can be hard to live with and many people become obese. What if we could re-engineer our genome to remove the tendency toward obesity? This might be important especially because obesity doesn’t necessarily kill people before they reproduce, so I suspect the selection pressure against it is relatively small. What gives me pause is the possible unintended consequences, about which more below.

His other point stuck in my mind because it had just come up in a conversation with a friend. Evolution is about surviving long enough to reproduce, and so some of the things that matter to us don’t matter to evolution. Green added that maybe it wouldn’t be a bad thing to help evolution along and provide some of the things for ourselves that evolution doesn’t care about, like a healthier post-reproductive lifespan. He mentioned a cryptoreligious thread in discussions of evolution, the idea that our nature and our genome are given to us by God, and therefore sacred, something we should not tinker with. However, I don’t think you have to be religious or believe in God to feel deep reservations about the wisdom of changing our genome. What worries me is whether we have adequate knowledge and humility and foresight to do better than nature at creating ourselves–not because nature is sacred, but because of the complexity of the systems involved.

Obviously we intervene in nature all the time; I live in a climate-controlled building and wear glasses and take a calcium-channel blocker for hypertension, for example. But it’s obvious that in improving human life and rearranging nature more to our liking, we’ve damaged the natural systems we rely on for clean air, drinkable water, and livable weather, not to mention the toll we have taken on other species. We haven’t found a balance between improving our lives and living sensibly and sustainably within the bounds of the planet on which we depend. Given our cavalier and reckless treatment of the biosphere, why assume we would be any less short-sighted or selfish or ignorant when dealing with our genome?

Furthermore, even though the human body is far from perfect, the limitations we’d face in improving it are not that different from those faced by the evolutionary forces that created it in the first place over generations of compromises and contingencies, and we don’t yet understand very well the trade-offs and interactions that went into making us who we are. We’re not intelligently designed; we’re cobbled together out of whatever worked in previous generations, plus whatever was suboptimal but not bad enough to outright kill previous generations, plus a lot of things that don’t matter one way or another to evolution but arose as byproducts of something else. I sometimes think the human body is like a generations-long software project that has accreted all kinds of mysterious bits of code for which the purpose is not obvious. Things are connected in ways that are not clear; old structures or processes are pressed into performing new functions. The human body is in some ways an amazingly complicated Rube Goldberg contraption, and I don’t think we understand it nearly well enough to improve our genome significantly.

Several years ago my son was watching a nature program on TV while I was doing housework. As I moved in and out of the living room, all I caught was an occasional sentence or two from the show, totally out of context; one of these, intoned in a portentous nature-show voice, was “But mating is a risky business.” Although I’m sure the show was not about humans, I had to agree. But if you think humans sometimes have it tough, consider the Australian cuttlefish.

The male/female ratio is drastically skewed, with as many as 10 males for every female. The big strong males can fight off competitors if they can persuade a female to mate with them, but the smaller guys try a smart trick instead. Cuttlefish are able to make astonishing changes in their appearance to disguise themselves from predators; on TV once I saw what looked like a video of some kind of plant sitting on the sea floor, until part of it seemed to turn into a cuttlefish and swim off. Even after the video sequence was replayed, I couldn’t believe my eyes. So a small male cuttlefish transforms himself into what looks like a female, so he can sneak past a larger male and get close to the female that the bigger fish is guarding. The big fish doesn’t chase him off, because presumably he appreciates having another female, but the smaller male then has a chance to mate with the real female.

The really surprising thing is that the females prefer these guys, being more likely to mate with them and, more to the point, let their eggs be fertilized by them. I’ve wondered about the brains of cuttlefish; I saw the video of that magical transformation on a show about looking for intelligent life elsewhere in the galaxy, and the point was that there are plenty of complex brains down here that would never be apparent to anyone on another planet; some of them are barely known to those of us who live on this one. The cuttlefish have some huge number of chromatophores that change color and size to allow them to make dramatic changes in appearance, and their brains, the processors that control all of the chromatophores, have to be fairly large and sophisticated. I don’t want to anthropomorphize these female cuttlefish and cheer them on for choosing wit over brute force, but it is a cool story anyway. (And as I recall, the reason the cuttlefish have this elaborate system of mimicry in the first place is that they have few other defenses; their success against predators lies in craft rather than force. That’s one reason I find them so interesting.) The only down side for the small males is that sometimes they look so convincingly female that a larger male will try to mate with them. Nobody said it would be easy. After all, mating is a risky business.

You can learn more about cuttlefish and other cephalopods at the Cephalopod Page.