Thursday 22 March 2012

The Noblest Predator

When we think of the kinds of predators that inspire respect and admiration, the creatures we put on coins and flags and coats of arms, it's often animals like lions, bears and eagles we choose. I'd like to suggest that these aren't necessarily the models of courage and nobility we should be inspired by, and nominate instead an unjustly maligned predator as a moral exemplar.

The lion, for instance, while certainly a majestic looking beast, is a cruel and murderous patriarch. When a dominant male (or usually a gang of two or three) takes over a pride (by the violent overthrow of the previous regime), the first order of business is to kill any nursing cubs, so as to free up the mothers to start a new litter with the invaders. Can we think of this as anything but reprehensible?

Such behaviour isn't limited to lions. Mother bears are well-known among mammals for their fierce defence of their young, but part of the reason the cubs need such defence is that other bears will think nothing of eating someone else's cubs.

But quite apart from the intraspecies conduct of these predators, there are moral issues with their predatory styles, as well. For one thing, most predators are cowardly, when you think about it: they attack the sickly and frail, the most vulnerable prey they can find, as if their sharp teeth and claws weren't enough of an advantage. And many predators go after prey very much smaller than themselves, so much so that we don't even really think of them as predators; consider the baleen whales, who lazily scoop up vast numbers of invertebrates, small fish and anything else unfortunate enough to be in the wrong  volume of seawater, swallowing their prey whole to be digested alive en masse. I sometimes suspect that the majority of individual animals in the world spend their last living moments in the stomachs of such predator like whales and anteaters, who simply gulp down tiny victims without even doing them the courtesy of a merciful euthanizing chewing.

It is, after all, generally only the predators with enough courage to take on prey closer to their own size who bother to kill before eating. Not out of any compassion for their victims, mind you; it's just easier to eat a zebra when it's no longer trying to kick your teeth out. And the methods used are far from humane, anyway; teeth and claws, drowning, suffocation, venom, even electric shock in the case of certain sea creatures. There are even predators, like the ichneumon wasp, who go out of their way to keep their prey alive as long as possible so as to keep it fresh for when the eggs laid inside the hapless victim hatch.

Even on those rare occasions when we humans, the most terrifyingly effective killer of other creatures on the planet, bother to concern ourselves with minimizing the suffering of our prey, the fact remains that we kill what we eat, and there really is no such thing as a nice way to kill someone.

So allow me to recommend as the most noble, heroic and courageous predator this: the lowly mosquito.

The mosquito lives most of its life as a vegetarian, after all. Loath to harm another sentient creature, it takes most of its sustenance from plant juices. It is only when a female finds herself with developing eggs that she is compelled to take a meal of animal blood, and not even for her own sake, but solely for the benefit of her children.

Yet what does the mother-to-be mosquito do when she needs protein for her babies? Unlike more cowardly predators, she does not seek out smaller, more vulnerable creatures to kill. No, she doesn't pick on someone her own size; she goes after prey that dwarfs her by many orders of magnitude. Indeed, she often goes after that very deadliest of animals, Homo sapiens. And not to kill, but to humanely harvest a tiny quantity of blood, ideally without causing the slightest discomfort whatsoever. (A mosquito does not want to be noticed, after all.) Less than a drop of blood is all she seeks, never to be missed by the donor, and that only to feed her babies. And to get it, she faces the grave risk of being smashed into paste by her gigantic prey.

Now, it's true, of course, that mosquitoes are blamed for many human deaths annually, as diseases like malaria are spread by insect bites. But it's not fair to hold the mosquito responsible for what is really done by the malaria parasite; the mosquito is if anything another victim of the parasite's exploitation. Indeed, just counting sheer numbers, the number of mosquitoes slain by pesticides and other measures aimed at controlling the spread of insect-borne diseases is astronomically larger than the number of humans who will ever have lived, let alone be affected by all of those diseases combined. I expect that if the malaria parasite were to go extinct tomorrow, few creatures would have more cause to celebrate than the mosquito.

So let us admire the courage and compassion of the noble mosquito, even if we don't stop swatting them.  And best of all, these valourous little bloodsuckers don't sparkle!

Wednesday 14 March 2012

Obsolete Ruminations on Obsolete Hominids

     I've always been intrigued by the fact that Neanderthals actually had brains that were, on average, bigger than ours, despite our habit of dismissing them as crude brutes who never had a chance against us refined and sophisticated Cro-Magnon Homo sapiens types. While it's a mistake to assume that intelligence is always directly correlated with brain size, it isn't completely ridiculous to wonder if maybe H. neanderthalensis was actually smarter in some ways than we are.
     I once read somewhere that there was some question as to whether or not our Neanderthal cousins had the capacity for language, based on an examination of their bones that seemed to suggest they didn't have the same vocalization abilities that we do. This got me to thinking about the role of language in our own species' success, how it could have helped us out-compete the Neanderthals, and its implications for our culture generally. Individually, they might well have been smarter. But without language, each individual Neanderthal would have had to figure out new innovations largely on her own, perhaps with some hands-on demonstration by others, but essentially by discovery anew each time. In contrast, the somewhat dimmer  H. sapiens might take longer to come up with a concept, but as soon as any member of a sapiens clan worked something out, everyone else would know it pretty quickly.
    As an example of this process, I think of my own experience in studying math in school. Although the rote memorization of the times table in elementary school bored me to tears, I eventually discovered the beauty of mathematics, and took great pleasure in exploring mathematical ideas. For most of junior high school and the first two years of high school, I did very well, ignoring the teachers for the most part and coming up with my own way of solving problems on the spot. Many of my classmates, however, struggled with trying to memorize and follow the teachers' instructions (and not "getting it" as intuitively and naturally as I did).
     This worked just fine for me, up until Grade 12, when the math suddenly seemed to get more complicated. It wasn't that I couldn't do it; I could still look at a problem, take it apart and derive a solution. But the complexity of the problems in calculus and polynomials was such that it would take me more than the available time to finish the exam. My grades plummeted, and while I did pass (barely), my classmates (who actually listened to the instructions) did much better, even if they didn't always have as deep a feel for the math as I did.
     So I wondered, then, if the Neanderthal predicament was like mine had been in math. On her own, she would have been more than a match for any individual modern human: stronger and smarter. But modern humans aren't on our own; we inherit, through language, a vast amount of knowledge that we don't have to rediscover for ourselves. We don't need to be so smart as individuals, because we share our smarts better.

     These speculations are, at least in the case of Neanderthals, obsolete. It turns out that they probably did have language, based in part on genetic evidence that they had a gene known as FOXP2, which is associated with language. Yet even if my speculations don't actually solve the mystery of how our ancestors survived and the Neanderthals didn't, they have at least given me an interesting insight into the role of authority in human culture. It's always puzzled and even alarmed me the extent to which people are willing to defer to an authority, whether it be an charismatic leader, a peer group or a text. If it's written down, or if it's the wisdom of our ancestors handed down from times past, we're inclined to accept it without question, and I suspect this isn't just something we're taught to do; it seems to come naturally. (It's also taught, of course; I certainly remember the emphasis on citing authority in law school).
     It's tempting to lament this as a curse, the stifling of individuality and slavish unthinking obedience to tradition, but it's not altogether a bad thing, and neither is it all there is to human nature. After all, we also need to have a certain amount of individual creativity to provide the ideas that are then transmitted and received this way. And I have to admit, I found that, when I took linear algebra in university, studying hard and following instructions really did help me to do better within the time constraints, even if it wasn't in my nature.
     But I do think it's important for us to be at least aware of our innate tendency to defer to authority, and maintain a sensible balance. Tradition is useful, and ideas that have been around for a long time can generally be assumed to have passed some kind of test, so we should be inclined to take them seriously, but we should never be afraid to examine them critically as well. A bit of the Neanderthal nature is healthy.

Thursday 8 March 2012

Some Observations on Neuropathy

     I've recently finished with chemotherapy for colon cancer, which has afforded me the opportunity to experience some things that, while not necessarily pleasant, have been kind of interesting. In particular, right now I'm thinking about the composite nature of tactile senses in a way it never occurred to me to consider before.

     We all know that the colours we see are really just distinct blends of only three basic colours: red, blue and green. That's because our retinas contain photoreceptor cells that are particularly sensitive to one of these three ranges of frequencies. Primates have better colour vision than most other mammals, which only have two different colour receptors. Most birds have four, giving them a greater sensitivity to distinct colours.
     Likewise, the many flavours we can distinguish are generally made up of composite signals from just five types of receptors on our tastebuds: bitter, salty, sour, sweet and umami. Our brains recognize one particular proportion of these signals as garlic, another pattern as lemon, and so on.
     Indeed, hearing is also a composite sense; tiny hairs are located at a different resonant lengths within the cochlea, and thus are sensitive to different frequency inputs. What we distinguish as a single sound (a violin, a trumpet, a human voice) is a complex blend of the inputs of hundreds of different audio frequencies.

     Now, one of the side effects of oxaliplatin (one of the chemotherapy drugs I was on) is what they call peripheral neuropathy, or damage to the nerves leading to the remote (peripheral) parts of the body: fingers and toes. In short, my fingers and toes are uncomfortably numb. However, it seems that this neuropathy doesn't affect all receptors equally. While I've lost most of the pressure sensors in my fingertips, I can still receive signals from the pain and temperature receptors, which has had some interesting (if annoying) effects.
     First, the pressure receptors have by far the finest resolution, as Braille readers demonstrate. The pain and temperature receptors don't need to be as precise about location; it's enough that the brain knows a particular fingertip is risking damage without worrying about what square millimeter is at risk. This means I can't sense things as precisely with my fingertips as I could before the treatment. I have trouble buttoning my shirt, and I can't play the guitar without visually confirming I'm putting my fingers on the right strings and frets. It also means my fingers constantly feel kind of greasy to me, as if a fine layer of oil is preventing me from detecting the tiny variations in altitude of a surface that would normally show up as small local variations in signals from pressure sensors.
     But I can still sense textures to some extent, and I think this is due in part to the role of what we call the pain sensors. The pain sensors are triggered by extremes, stresses of pressure or temperature that threaten to damage tissues, but they seem to have a wide range of sensitivity, and I think that normally they must play a role in sensing things that are not strictly speaking "painful". For example, when feeling the edge of a knife, one doesn't apply enough pressure to actually suffer any damage, but the relatively extreme stresses on the tissues do trigger a mild pain signal which, combined with the pressure and temperature signals, forms a composite tactile image of a sharp edge. The composite signal doesn't register as painful at all, but the presence of a certain amount of the pain signal is part of what gives the feeling of sharpness.
     I am finding I sense the sharpness of surfaces, like the edge of a fingernail, as sharper than normal. I believe this is due to the "pain" signal making up a bigger portion of the composite input, since the pressure sensors are providing very little signal. It doesn't hurt, exactly; it just feels like edges I touch are sharper than they were before the treatment.
     In a way, it's sort of like the reaction to cold I had at the very first cycle. Touching cold things was startling; it's not that they felt colder than usual, but just more vividly cold. It was sort of like having just cleaned my glasses and then seeing the world much more clearly all of a sudden. (Subsequent rounds of chemo made the effect worse; instead of just feeling vividly cold, handling something right out of the fridge was like grabbing a live wire, a very nasty shock.) I am not sure how to interpret this experience, because the attenuated pressure sensitivity hadn't kicked in yet.

     Anyway, it's been fascinating to be able to take advantage of this experiment, much as I'd prefer to have learned this stuff second-hand.