by Simon Barnes
The segmented nature of annelids gives them movement. By changing the shape of individual segments in sequence, they can move by rippling themselves along. They move by peristalsis: if you like, they sort of swallow themselves along. Each segment is more or less the same. The front one is, however, different. Most of us would wildly term this the “head”. Quite a good name for it, but it’s actually the prostomium: in other words, it’s a head, but not as we know it. It contains brains and sense organs, so I’m tempted to ask, what more do you ask of a head? But an awful lot about invertebrate life – correction, an awful lot of all non-human life – is counter-intuitive. The final segment – would humans intuitively call this the bum? – is called the pygidium, and unsurprisingly is the location of the anus.
These more-or-less-identical body segments contain a shared gut, nervous system and circulatory system. Some species breathe through the skin; others through gills. You’d have thought that worminess would be a relatively limited design possibility, but that would be to underestimate the power of evolution, which can outstrip the human imagination any day of the week. The Christmas tree tube worm puts out spiral whorls of blue tentacles; it’s a filter feeder from tropical reefs. It’s spectacular, in its small way, not much more than 2 inches, 5 cm long. The sea cucumber scale worm has adopted a way of life that parasitises sea cucumbers. The Pacific feather duster worm takes the shape of a daisy. And Gipp’s landworm can reach 3 m, 10 feet, in length. Which is pretty impressive, but there are longer worms found in the phylum of ribbon worms. So there’s something to look forward to.
Good old Ratty
“Do I contradict myself? Very well, I contradict myself. I am large, I contain multitudes.” Words of Walt Whitman. We humans hate rats and mice; we humans are perfectly prepared to love rats and mice. We are all of us at least as large as Walt. I was in Bradfield Wood in Suffolk with people from Suffolk Wildlife Trust. We were there for a project that had touched people’s hearts. A sweet, charming, beloved creature has returned to the hazel coppicesI within these woods and it has given great joy. The very sight of a single living specimen is enough to trigger the cuteness reflexII in all human beings, even the most macho. Che cariiiino, how sweeeeet. Nor am I immune, au contraire: one look at them and everybody goes all soppy. You’d do anything for them. I am reminded of Douglas Adams,III writing on the near-extinct flightless parrot of New Zealand, the kakapo: “If you look one in his large, round, greeny-brown face, it has a look of serenely innocent incomprehension that makes you want to hug it and tell it that everything will be all right, though you know it probably will not be.”
Dormouse. The creature the Mad Hatter and the March Hare tried to stuff into the teapot, who told Alice the story of Elsie, Lacie and Tillie, the three little sisters who lived at the bottom of a treacle well. Linda, the beautiful heroine of Nancy Miltford’s The Pursuit of Love, is having tea with her awful husband on the terrace of the House of Commons: “ ‘Oh shut-up, Tony,’ said Linda, bringing a dormouse out of her pocket, and feeding it with crumbs.”
But the dormouse isn’t dependent on its literary connections for its charm: charm is its birthright. Tiny, with enormous eyes, and with bright-ginger fur, this is a beast to soften the hardest of hearts. It’s a muroid rodent, but we are perfectly prepared to love some of them every bit as much as we hate rats and mice. Suffolk Wildlife Trust found it comparatively easy to raise money from the public and from grants for their dormouse projects: there is nothing controversial or divisive about dormice. They are the sort of creatures we instinctively feel we ought to have around. As a result, they were reintroduced to Bradfield Wood, at first with artificial nesting boxes and artificial feeding, a “soft release” in the jargon, so that they could get the hang of wild living without dying in the attempt. We were there to count them and to see how well they were doing.
Dormice have a reputation for sleepiness. They are serious hibernators, and spend half the year asleep. But when they are awake, they are bold, acrobatic and dynamic. The first dormouse was investigated by Alison Looser, who had just acquired her licence to handle dormice and was working on the project under the wise and experienced Simone Bullion. Alison carefully inserted a hand into the nest box and the rest was a flash of ginger lightning as the dormouse ran up her arm and vanished into the tangled canopy of the hazel. Well, so much for weighing it and gathering other important data: but it looked in pretty good shape to me. (I should add here that Alison’s technique is now as swift and certain as you could wish, and she is a crucial member of the Suffolk Dormouse Group.) The rest of the day we progressed rather more calmly from nest box to nest box, counting one dormouse after the next. The dormouse is impossibly tiny in your hand, pushing its face between a tight circle of finger and thumb. Their home is up in the canopy, where they run and leap at high speeds, almost weightless, feeding on hazelnuts in season, flowers, fruit and insects. As I write, the Bradfield dormice are now in their sixth generation following the release in 2006. In 2011 Bradfield held more dormice than any other wood censused in Britain. And joy has been unconfined.
We are prepared to love rats just as much as mice. There is a river – technically a beck, because it’s seasonal – that flows through the house I used to live in, with a bridge that crosses it. From this bridge I have seen one of the most entrancing sights of a lifetime spent looking at wild animals: rats. “Absorbed in the new life he was entering upon, intoxicated with the sparkle, the ripple, the scents and the sounds and the sunlight, he trailed a paw in the water and dreamed long waking dreams. The Water Rat, like the good fellow he was, sculled steadily on and forbore to disturb him.”
Ratty, good friend to Mole, was, at least to me, the real hero of The Wind in the Willows. And out in the Wide World – as the Rat says: “That’s something that doesn’t matter, either to you or me… Don’t ever refer to it again, please” – water voles, as they are more properly called, are met with almost universal delight. Whenever I say that I have sat on my bridge watching two water voles at the same time pattering about in the wet, puddled hollow of the half-dried-out river, splashing, swimming, plunging and squatting on their haunches to nibble pawfuls of salad, I am greeted not with disgust but with envy. I may have rats on my premises: but I also have water voles. Voles are different from rats, but not dramatically. It’s the same muroid body plan, the same pointy head and naked tail. One species we love, the other gives us the creeps. David Attenborough confesses to a phobia about rats. But everybody loves dormice and water voles.
Everybody loves barn owls and kestrels as well. I’m not suddenly bursting into the next class of vertebrates and talking about birds here: barn owls and kestrels depend for their survival on muroids, most particularly on the short-tailed field vole. You may have met bank voles if you have a cat and live in a mildly rural area: when the cat brings you a gift of something that looks more like a fat, furry teddy than a slimline mouse or shrew, you’ve probably got a bank vole. Conservationists used to tell us that barn owls and kestrels are “important” because they keep down “pests” like rats and mice. These days, we’d be more inclined to say that muroids in general and field voles in particular are important because without them we’d have no barn owls or kestrels.
But we are, in certain circumstances, prepared to love rats and mice for their own sake. I have seen dormice dance in the canopy, I have seen Ratty plain. Is that not something to be envied?
* * *
I. Coppicing is an immemorial method of woodland management, and it works particularly well with hazels. The tree is felled to just above ground level; it then produces half a dozen or more dead-straight wands, which were traditionally harvested for building and other purposes. You keep the coppice going by cutting every 10 years or so; the coppice stool spreading and producing more and more wands. A coppice stool can be half a millennium old. The technique produces a dense thicket of hazel which is a good thing for wildlife, especially dormice and nightingales.
II. The cuteness res
ponse is generally thought of as a useful evolutionary development in humans. Human young need care and protection for many years: it makes sense, then, for adults to feel protective of them. The triggers for this response are large eyes, relative to head, and flat faces. Adults who retain such traits are considered more trustworthy, warmer and more employable than others. Stephen Jay Gould, scientist and writer, described in a famous essay the changes Mickey Mouse has been through since he was created in 1928: his eyes becoming larger, his nose less pointy. In short, he has become cuter. Teddy bears, as already noted earlier, have much flatter muzzles than real bears, and larger eyes: and for the same reason.
III. Douglas Adams was the author of The Hitch-Hiker’s Guide to the Galaxy.
Trio for piano, bassoon and earthworm
Charles Darwin was every bit as large as Walt Whitman, but the contradictions he contained were those of method rather than conclusion. When we come to Darwin, we are usually concerned with his ability to think on the grand scale: majestic, sweeping, universal, world-changing. But he was able to reach extraordinary conclusions because his work method was detailed, meticulous and minute. You’d have thought him piffling if you didn’t know better. There are big ideas lurking in the tiniest facts – the fall of an apple, for example – and Darwin was at his best pottering about among details of stuff that most people didn’t think worth a damn… but always thinking, always theorising, always prepared to make a daring sortie from the great citadel of fact.
Darwin spent many years throughout his life studying earthworms. His last publication, which came out six months before his death, was The Formation of Vegetable Mould through the Action of Worms: with Observations of Their Habits. It sold faster than the Origin when it first appeared. It was Darwin who established the fact that worms are vital to humans. Plant life on an agricultural scale would not be possible without worms. Earthworms convert organic matter (dead leaves, animal droppings) into humus, in which plants can grow. One wormcast – that is to say, its faeces – contains 40 per cent more humus than a comparatively sized sample from anywhere in the top nine inches, 23 cm, of soil. By ingesting soil particles and passing them out again, worms make minerals and nutrients available to plants. Their constant movement through the soil keeps it aerated and drained. Darwin reckoned the worm population at 53,000 per acre, but that is now considered conservative. Even in poor soil the number is more likely to be 250,000; in rich soil it will be something like 1,750,000; according to other inflationary estimates, six million. In a fecund cattle pasture, the biomass of the worms beneath the surface is likely to be greater than that of the cattle grazing above it. “It may be doubted whether there are many other animals that have played so important a part in the history of the world as have these lowly organised creatures,” Darwin wrote.
There are around 6,000 species of earthworms, and they are distributed across the world. They are hermaphrodites; they will come to the surface after rain to meet and mate, it being hard to do so underground. There the couple will exchange sperm and both will go away and produce a cocoon full of eggs that hatch out into wormlets. They are so important to human life that earthworms are farmed commercially. A loss of earthworms would be disastrous for humans – and there is a threat to them in Britain and elsewhere in Europe. New Zealand flatworms have got into the ecosystem through imported contaminated soil and plant pots. They prey on earthworms and have no natural predators in Europe.
Earthworms keep humans alive; they also change landscapes. Darwin examined the work of earthworms around Stonehenge. At his home, Downe House in Kent, he laid out objects on the ground and left them there for 20 or 30 years to see what would happen: how long it would take before the soil, shifted by the worms, consumed them. He dug a trench to see how far they had gone underground. He created a large instrument to measure the action of worms, and called it the wormstone; you can still see it at Downe House. Darwin was a great worrier at problems. He was always prepared to think in unconventional directions, and was never shy of testing a thought in action. For example, he wondered if earthworms were affected by music. So he got his wife Emma to play the piano to worms, and his daughter Frances tried them with the bassoon. Darwin himself whistled. There was no response: but negative data are also good data.
Many people have wondered about Darwin’s delight in such apparently trivial subjects as earthworms. From the meaning of life to the action of worms seems to some a fairly precipitous descent. Stephen Jay Gould, one of the greatest science writers that ever picked up a pen or struck a keyboard (mentioned in the previous chapter’s notes on the cuteness response), wrote a spirited defence of Darwin’s worms in one of his essays for Nature magazine. It was, he said, all about gradualism. Darwin’s theoryI of natural selection meant that the forces of nature require vast amounts of time for the gradual changes to assert themselves from generation to generation, as antelopes stretched up towards the highest leaves and eventually – eventually – became giraffes, doing so because individuals with longer reach were more likely to live longer and so pass on their advantage to their long-necked offspring – who would do the same thing themselves, and on and on. The action of worms brings about very slow, very gradual changes to a landscape: changes that are imperceptible from day to day, but which are measurable over the course of a human lifetime. And in many lifetimes the changes that worms bring about must, of their nature, be massive: earth-changing. The notion of gradualism could not be demonstrated more clearly. So there it is: earthworms make modern human life possible and they help to explain how humans – and every other living being – got to be the way they are.
* * *
I. The word “theory” makes all kind of mischief. In loose, conversational use it means a hunch, or a notion: I’ve got a theory that the stars are God’s daisy-chain. But a theory is not a mere hypothesis. In specialised scientific use, a theory is the only possible explanation of the known facts: as in the theory of gravity, and the theory of evolution.
Night-leaper
But we must celebrate the loveliness of rodents once more before we move on, and as we do so – we have no choice – we will celebrate yet again the virtuosity of nature. I was in Namibia. I had been travelling with some people from Save the Rhino, an excellent charity of which I am now a patron. One evening, after a day’s hard travelling, we left the blacktop and drove off into a fine wildlife area towards what turned out to be an excellent lodge. It was dark. We got out the bright spotlight and attached it to the car’s battery. I explained that I was by far the best qualified to use it. Fact is, spotlighting for game at night is hellishly good sport. The trick is to look for eyes: eyes that reflect back at you in the spotlight, as the eyes of a cat do when caught in a car’s headlights. Light bounces back from the tapetum, which is a light-gathering device at the back of the eye. This reflects extra light back onto the retina and helps an animal to see better in low light. We primates don’t have them, but most other mammals do.I It was a short drive, half an hour or so; I remember catching a couple of genets from their eyeshine in the trees. But then came the star of the night. I snared it with a glimpse of its eyes and then caught it in the full beam. For a moment it was mine.
And a more improbable thing you’d be hard pressed to find, no matter where you travelled. Somewhere between a hare and a kangaroo with a bit of squirrel and the merest hint of dormouse, the last in the expression of the face, the brightness of the eye (both being nocturnal) and the same ability to inspire the cuteness reflex. But before anyone could say aaaah (che carino!), it was gone. It had pinged out of the beam with an abrupt kangaroo leap for which there seemed to have been no preparation, as if it had simply released a hidden spring. I followed it with the spot, leap after leap, dark-tipped tail streaking out behind as a balancing pole. Front paws tucked demurely in front. Then it vanished.
Springhare. I’d seen them before, but this was a specially memorable sighting because I’d done the finding. Springhares do well in areas where the grass is too
poor and/or too periodic for antelopes and other large grazers. They thrive on floodplains, when the grass can be briefly superabundant after rains, but at other times is too short and sparse to support big grass-feeders. In other words, this is a vacant niche – or would have been if a rodent, of all things, hadn’t adapted to fill it. The springhare is a grass-eating rodent. The requirements of the niche are that the occupant is small enough to find the intermittent grass adequate, yet large enough to have the mobility to reach it whenever and wherever it appears. The springhare can be up to 43 cm, 17 inches, from head to the base of the tail, with another 48 cm, 19 inches, of tail.
But this is a size that brings its own problems. Springhares are small enough to be eaten by snakes and owls and mongeese,II but big enough to be a decent snack for a lion. Springhares have an awful lot of predators to avoid, so they have to be fast: really, seriously fast. The forces of evolution came up with the answer, and a rather unexpected one. Springhare: an unconventional masterpiece of a rodent.
* * *
I. Pigs and squirrels don’t, being in theory strictly diurnal; in practice pigs often operate around dawn and dusk, and even at night. Some night birds have a tapetum: owls, most nightjars, stone curlews, and the kakapo, mentioned a couple of chapters back. Why, then, do human eyes sometimes glow red in photographs taken with a flash? The very strong light reflects from the human retina, and takes its colour from the blood vessels that nourish the eye.