by Simon Barnes
And then in the space of a second I went from trudge to boat. Bang. There was scarcely any time-lapse at all between the sighting and the boating: no interim period of decision-making, swimming back to the boat and pulling myself out. It was an instantaneous transition. Shark–boat. And there was Ketut laughing amiably: “No eat!” he said. “No eat!”
“It’s all very well you sitting in the bloody boat and saying no bloody eat,” I said. “No. Home. Breakfast.” And still laughing at me, though ever so kindly, Ketut took me back to the shore.
Leaving me wondering forever after about my reaction to that shark. I can see it still, with immense vividness: one of those unfading snapshots, like the Definite Male Lion. But unlike the lion, this shark was, as Ketut said so eloquently, non-lethal. Not to humans, at any rate. It was a healthy size, a good 6 feet, but it was never likely to take on anything of a similar length. It swam directly beneath me, going about its own business with immense driving purpose. There was nothing to be afraid of. Why, then, was I afraid?
I still don’t know why it affected me so powerfully. Perhaps it was because of all the received information about sharks: the way we have turned them into fabulous monsters, film stars, bringers of death, far more fearsome than the far more lethal mosquitoes or for that matter, jellyfish. Perhaps fear of sharks is a purely modern phenomenon.I But perhaps not. Perhaps there is something atavistic in humans that responds to the sight of a shark. But there is a third possibility. Perhaps it was not the shark itself that inspired such decisive evasive action. Perhaps it was the fact that it was so completely different from every other living thing around me. It broke the pattern of normality: and that can trigger the flight-response in a prey animal. Many a time I have sat on a horse that has spooked and even tried to run from a wheely-bin: not because wheely-bins are terrifying but because this one wasn’t there yesterday. Wheely-bins are not threatening: unfamiliarity is. If it breaks the pattern, it’s time for action: every horse believes in the principle of better fast than sorry. In short, was it my over-civilised self that responded to the culture of Jaws and got me out of the water? Or was my ancient ancestral self seized with an ancient ancestral fear?
The shark was spectacularly unlike any other fish I had set my eyes on that morning, and there had been plenty. It moved in a different way. Most fish move with a rapid, almost imperceptible wriggle: this shark moved in long, bold, side-to-side lashes. Everything about it proclaimed its difference. The cut of its jib, what birders call its jizz, its mien, the impression it gave: all was different. This was not a fish as other fish are. It was another class of being entirely. And so in that one lightning moment, Zen-like, I was enlightened. Not about the meaning of life, but certainly about the meaning of fish. I understood why there is no such thing as a fish. In other words, after about 100 chapters and nearly 100,000 words, we have got the punchline of the fish joke. Why is there no such thing as a fish?
The fact is that “fish” is not a coherent term when it comes to taxonomy. It used to be thought that there were five classes of vertebrates: mammals, birds, reptiles, amphibians and fish. Now it’s all been changed. For a start, many classify reptiles and birds together, but what matters here is that there is no single class of backboned gill-breathing swimming animals. In fact, there are four of them. Each has found an approximately similar solution to the problems posed by an aquatic life: the same streamlined shape, a similar side-to-side swimming motion, the same way of gathering oxygen from the water. But these four classes are no more closely related to each other than we are to the red-eyed frog or to the kori bustard.
Four distinct classes make up the group formerly known as fish. The biggest one is the ray-finned fish, which include goldfish and are what we normally think of when we hear someone say “fish”. The second are the cartilaginous fish, which include sharks and rays. And there are two more obscure classes with far fewer members: the jawless fish and the lobe-finned fish.
A fishmonger is of course a person who mongs fish. The nonsense in that last sentence is not the penultimate word, but the last.
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I. In 2012 there were 118 shark attacks reported, of which 17 were fatal. Malaria kills 2,000 to 3,000 people every day.
True bugs suck
It’s the sound of the heat itself. The sound that proclaims an elemental truth: that no one should be expected to do anything but lie in the shade until it’s over. That’s the cicada, celebrated by Gerald Durrell in My Family and Other Animals: the insane heat of a summer afternoon on the island of Corfu rendered into sound by the indefatigable insect. It is a sound that thrills the traveller from a colder place, at least at first. Later it perhaps exasperates, soothing as fingernails on a blackboard, but finally it becomes the essential voice of the place. Cicadas turn up all over the world in the warmer places, and they love to sing, especially in the heat of the day when everything else is silenced.
Stillness –
the cicada’s cry
drills into the rocks
Another haiku from Basho: an insect epiphany. A cicada is a semi in Japanese but there’s nothing half-hearted about a cicada. Some of the species are pretty hefty: on Lamma Island they always seemed to be crashing into me, like flying Volkswagens, interrupting early-evening drinks with mad forays into human company, headbutting people, bashing into drinks and lying stunned and enormously winged on the table before they lumbered back into the air and flew off to continue their eternal chorus.
Perhaps cicadas bug you. If so, you have the blessing of science this time: cicadas are members of the order of Hemiptera, otherwise known as true bugs. They are named for the hard base to the forewing; Hemiptera translates as “half-wing”, but that’s not so terribly interesting. What true bugs can do, probably better than any creature that has ever evolved, is suck. They have sheathed mouth parts which form a beak – technically a rostrum – that can pierce tissue. Once the piercing has been achieved, they suck. Mostly they pierce plant tissue and suck sap. Aphids, which include greenfly, insects many gardeners wage chemical warfare on, are bugs. So too are the insects that cause cottony cushion mould, which has devastated citrus crops.
Some bugs prefer to penetrate animal tissue: bedbugs are rightly named, being true bugs. There are other bugs that suck vertebrate blood, some of which are vectors for Chagas disease, so it is possible that it was a South American bug that ruined Darwin’s health. The most picturesque members of this group are the assassin bugs. They prey mostly on their fellow invertebrates, and they can take on creatures much bigger than themselves. They do so by what is called external digestion.I They use the rostrum to penetrate their victim and inject a saliva that pre-digests its insides. They then suck it up like a child with a milkshake.
There are more than 50,000 described species of true bugs, some say as many as 80,000. That’s because the classification gets a little complex and controversial. But we can take a moment to admire the versatility of the Hemiptera, for the bugs have come up with many ways of facing the world. They include the water boatmen and water scorpions, and one of the very few marine insects, the Halobates or sea skaters.
Then there is the 17-year locust, which is not a locustII at all, but a cicada. There is also a 13-year locust, another cicada; both of these misnamed species are found in the United States, and as their names suggest, they appear once every 13 or 17 years. Like a plague, in fact, hence the name, given by people who knew the Bible better than the works of Linnaeus. These creatures spend the first 13 or 17 years of their life underground where, in the manner of bugs, they live by sucking, penetrating tree roots to suck out the sap. But every 13 or 17 years there is a sudden emergence: a dramatic explosion of rock-drilling sound. It’s celebrated in the Bob Dylan song “Day of the Locusts”. The great screaming dance of the cicadas continues for a couple of weeks, and naturally, it’s all about mating and egg-laying… and then the frenzy is over for another 13 or 17 years.
Why pick such a number? Stephen Jay Gould, already
met in these pages, says: “Many potential predators have two- or five- year lifecycles. Such cycles are not set by the availability of cicadas (for they peak too often in years of non-emergence), but cicadas might be eagerly harvested when the cycles coincide. Consider a predator with a life-cycle of five years: if cicadas emerged every 15 years, each bloom would be hit by the predator. By cycling at a large prime number, cicadas minimize the number of coincidences (every 5 × 17, or 85 years, in this case). Thirteen- and 17-year cycles cannot be tracked by any smaller number.”
This argument has been disputed, but it has a certain beauty about it, so I rather want it to be true. It has precisely the kind of mathematic perfection that is always so enticingly just out of reach to a non-mathematician. All the more so because in normal circumstances, numbers rather bug me.
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I. Spiders, as we have seen, use a similar technique.
II. True locusts are related to grasshoppers.
The stillness of salmon
A great sigh of disappointment at the nearest of near misses. You can’t not utter it: it’s part of human nature, part of animal nature; it seems torn from your very guts. And then another one – ahhhh, no! So close! But then comes a third, breaking the surface like a rocket, like a penguin only better, firing itself at the sky, wriggling like a mad thing, contorting itself in the air like a long-jumper seeking those extra centimetres – perhaps as many as 20 – with a hitch-kick technique, touching down and getting half an instant of purchase in the foaming exuberance of the summit – and for a moment it seems it’s going to be hooshed back to the bottom, but no, after a series of glorious triumphant shuffles in which its mouth seems to make contact with its tail on both sides of its body in less than a second, it’s through, cutting though the opposing waters of the pell-mell stream like an agile blade.
That is a salmon taking on all the water in the world as it scythes and knives its way upstream to the spawning ground, driven from the sea by the irresistible call to make more salmon,I a sight I witnessed at the Falls of Shin in Scotland. A salmon seems at first sight to be the perfect representative of the ray-finned fish: the great voyager, the unstoppable swimmer, the fish that’s crossed the barrier between salt water and fresh, and what’s more, is considered supremely edible. Salmon are also supremely fast and skilful, but at the end, they are supremely helpless as, the spawning done, they have nothing more to do with their lives except die. I have seen them hunted down in British Columbia by bears, and it’s a harder job than it looks while they’re still on the move. One of the bears I saw was presumably young, and certainly spectacularly incompetent: floundering after the fish like a Labrador, all misdirected enthusiasm and playful bounces. Eventually it settled down to look for pre-killed, half-eaten salmon that had been caught by bears who had mastered the art, eaten the tastiest bit, left the rest and moved on.
The image of the salmon leaping the fall is the most romantic in the fishy universe, a sight that spells out the truth that when it comes to motion through water, nothing is quite as good as a ray-finned fish. To tell someone that he swims like a fish is the most reckless compliment. Nothing has mastered the water quite as much as a ray-fin – and yet motion is not their masterpiece. The ray-finned fish’s true mastery of the water comes from stillness. In the motionless goldfish in the aquarium, suspended between surface and gravelly floor, unmoving, contemplating life in the profound way that only a goldfish can: that is where you find the true greatness of the ray-finned fish. Their secret is the swim bladder: with it, a fish can retain neutral buoyancy at any depth, not rising, not sinking and not needing to move a muscle. It can lean on the water as you lean on a lamp-post, it can lie in the water as you lie in your bed, and yet it can shoot off through the water as Usain Bolt shoots off along the track. More than to any other creature on the planet, water is home to the ray-fins.
The swim bladder is part of us, too. That was one of the insights of Charles Darwin: “There is no reason to doubt the swim bladder has been converted into lungs [and that] all vertebrates with true lungs are descended from an ancient prototype.” Every breath we take reminds us that our ancestors are watching us, telling us of our line’s piscine past.
Most vertebrates are ray-finned fish. There are almost 30,000 species described. With a few odd exceptions – thermal pools, the Dead Sea – wherever there’s water there are ray-finned fish. One of the weirdest and biggest is the ocean sunfish, a creature which inexplicably likes to bask flat-out on the surface of the sea. I saw one from a boat off the coast of Cornwall, lying there like an enormous flabby dinner-plate. They can reach 11 feet, 3.4 m, across and weigh as much as half a ton, 1,000 kg. There are plenty of contenders for smallest; anyone who has visited an aquarium has marvelled at the little shards of flickering subaqueous light that are fully-formed adult fish. The prize perhaps goes to the dwarf pygmy goby at 0.3 inches, 7.6 mm.
The weird thing about the great biodiversity of ray-finned fish is that they all look pretty much the same. That’s inevitable, because travelling through water is a hard job, much harder than moving through air. That makes streamlining essential, and since there is really only one way of streamlining there is no vast divergence in body plan. The class of mammals brings us giraffes and elephants and hippos and mice and bats and kangaroos. The ray-finned fish bring us salmon and perch and carp and sturgeon and pike and catfish and cod and mullet and they’re all roughly the same shape. That rather blinds us to the great diversity of fish. It’s also true that, not being aquatic animals ourselves, we are never as intimate with fish as we are with birds and mammals. The ray-finned fishes are the great undiscovered ocean of biodiversity among us vertebrates.
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I. Bill Bryson, in one of his travel books, draws a cartoon of two salmon at the foot of the waterfall. One says to the other: “Sod it, I think I’ll just stay here and have a wank.”
Let copulation thrive
The simple fact of flight: is there anything to touch it for sheer glory in the wild world? Birds, more than any other group in the Animal Kingdom, have fascinated humans across the ages because they can fly. Among all the inverts, it’s butterflies that enthral humans above all others because they are beautiful and they fly most conspicuously in the daylight. When we talk of the human spirit taking wing, we mean nothing but greatness and glory and optimism. James Joyce called himself Stephen Dedalus in Ulysses and in A Portrait of the Artist as a Young Man: naming himself for Daedalus, the man who invented human flight, whose son Icarus flew too close to the sun.
How many times, I wonder, have I raised my eyes to the heavens to gaze at some avian superstar: say, a bateleur eagle, gliding in glory across the valley, as I pause, just for a moment, to slap irritably at some bothersome insect. How irritating is a bloody fly when my soul is given up to the glories of flight? And yet nothing flies like a fly. Observe the houseflies in your kitchen: their complete mastery of three-dimensional space. They can be fast and direct; they can swerve and jink at speed, as anyone who has tried to kill one well knows. They step into the air as you and I step onto an escalator: a transition so straightforward it’s hardly a transition at all. They can alight on anything, floor, wall, ceiling: it’s all one to them; the transition back down to solid surfaces is just as simple. They are swift, agile and wholly controlled: surely no other group of animals on the planet is so completely at home in the air.
But we are curiously selective in the animals we celebrate. To stop in wonder at the flight of a fly is something only a child would do, or a drug-addled hippy, or an entomologist. And most people would call an entomologist a nerd, believing that a rare passion is something to be despised.
But consider the fly for a moment. By fly, I don’t mean the great wealth of insects that have had the word “fly” attached to their names: I’m not talking butter or caddis or scorpion or dragon or stone or saw or may. I’m talking about flies, true flies, if you like: but anyway the great group of two-winged insects that are classified toge
ther as Diptera. About 120,000 species have been described so far: a conservative estimate would say that was about halfway to completing the job. A quarter of a million different species of flies: a quarter of a million different species of two-winged hyper-agile flying machines.
Most flying insects have four wings and that’s a system that operates well enough. As we’ve seen, it’s given a dragonfly the best flat-out forward speed in the entire class of insects. But for all-round agility combined with power, the two-winged pattern is superior, which is why flies have lost the second pair of wings. They haven’t done so by just letting the damn things go. The hind wings have become modified into a pair of specialised organs called halteres. Their function is to tell the fly precisely where it is in space. Any learning pilot will tell you how hard it is to know where you are in the sky: the novice spends most of his time in the air looking at the artificial horizon, which tells him whether or not the plane is straight and level. The halteres pass on all kinds of complex information that allows the fly to compute its exact whereabouts. That’s what gives him the edge in manoeuvrability, its complete mastery of transition. A fly understands three dimensions better than any other flying creature.
The Diptera include the flies that bother you in the house and at a picnic. They also include the flies that bite horses and explode in blood when slapped, for they are another rare example of an animal I can kill without conscience. The Diptera also include the hoverflies, midges and gnats. I always love the sudden anticipation of spring on a bright day in late winter when the barest trace of warmth encourages a swarm of winter gnats, which emerge to hang in the air in a cloud of fellow dancers, males all looking for a female. The strategy behind this preposterously early appearance is to get the job of dancing and mating and breeding done before the hordes of insect-eating birds arrive to spend their summer in Britain.
