The Hunt for the Golden Mole

by Richard Girling

  At the first level, life is divided into kingdoms. Linnaeus recognised just two – animals (Regnum Animale) and plants (Regnum Vegetabile). Two and a half centuries of exploration, analytical sophistication and genetic science have added four more – fungi, bacteria, archaea (single-celled micro-organisms) and protoctista (aquatic organisms including algae, seaweeds, protozoa and slime moulds). The kingdoms are then subdivided into phyla (plural of phylum), according to their basic characteristics. There are a great many of these, but the most important from the perspective of a mole-hunter are the Chordata – broadly, creatures with a spinal cord. Phyla are then split into classes. In animals there are six – mammals, birds, fish, reptiles, amphibians and arthropods (creatures with more than four jointed legs, including insects, spiders and crustaceans), each placed within the appropriate phylum. The classes then break down into orders. Typically there is no firm consensus about the exact number of mammalian orders, their names, and which species belong where, but the number seems to hover around twenty-six. They include, for example, the self-explanatory Carnivora, Rodentia and Primates, though of more particular interest to us is the order Afrotheria, which includes the golden moles.

  Orders then separate into genera, or families, and the genera into species. It is these two last, genus – Homo – and species – sapiens – that comprise the scientific name. Humans therefore share with golden moles their kingdom (Animalia), their phylum (Chordata) and their class (Mammalia), but diverge at the level of order. As relationships go, it’s pretty remote. Other relationships are becoming more or less distant as DNA testing and molecular biology are reshaping the tree. Branches are lopped off, turned upside down and grafted back on different boughs. Golden moles, it turns out, are perfect examples of the unreliability of the old Linnaean method of grouping lookalikes. Their appearance, habitat and behaviour all so closely resemble the European mole’s that their family relationship is obvious – obvious, that is, but wrong. In phylogenetic terms their shared common name could hardly be less appropriate.

  False gold – European moles trapped in an English garden. The pale one is the colour of marmalade, but no relation to the golden moles of sub-Saharan Africa

  The European mole, plague of field and garden, belongs to the order Eulipotyphla, which also contains the shrews (Soricidae) and hedgehogs (Erinaceidae) as well as forty-two species of ‘true’ mole (Talpidae). Golden moles are of the order Afrotheria, which contains several other species that bear misleadingly strong resemblances to the Eulipotyphla. Madagascan tenrecs, for example, could easily double for European hedgehogs. But the golden moles are acquiring relations as well as losing them. Elephant shrews, for example, were first described in the 1880s and given their common name because they looked so much like all the other known shrews – long noses, sensitive whiskers and an appetite for worms and insects. In the 1990s, however, it was revealed by genetic sequencing that they were not shrews at all but twigs on a faraway branch that contained not just golden moles, tenrecs and aardvarks but was a near neighbour of some of the most improbable relatives it is possible to imagine – manatees, dugongs, hyraxes, marsupials and elephants. It was not that European and golden moles had descended from a common ancestor, but rather that natural selection had adapted them to their similar environments, a perfect example of what scientists call morphological convergence. As Max says, physical similarity very often is a good indicator of family relationships (horse, donkey, zebra, for example, or the cat family), but you can see how unknowingly difficult life was for scientists like Linnaeus who had only the evidence of their eyes to guide them. A shrew is not always a shrew. A mole is not always a mole.

  Calcochloris tytonis and its golden brethren constitute the family Chrysochloridae, and were originally described 250 years ago by Linnaeus himself. DNA and fossil evidence suggest that their clade, the order Afrotheria, first branched out some 100 million years ago. The world then was unlike anything humans have ever known. Antarctica seems to have been some kind of tropical paradise. Evolution had just produced the first bees, but ants still lay in the future, as did Tyrannosaurus, bats, butterflies and, a very long way down the track, humans. The earth itself was heaving with massive uncertainties. Shifting tectonic plates were tearing apart the great lumps of rock that would morph into South America and Africa, and it seems probable that the proto-Afrotherian, whatever it looked like, was isolated on the African side. A million centuries later, we can thank it for the aardvark, the elephant and the eponymous ‘shrew’.

  And also, of course, for golden moles. In the 250 years since their discovery, they have proved remarkably difficult to know. Gary Bronner attributes this to the remoteness and smallness of their ranges, and to the typical shyness of small blind creatures that spend their entire lives underground. This rules out casual sightings and makes them extremely difficult to track down. More pertinently perhaps (for we are talking about Africa), the abundance of more charismatic animals has denied them the attention they might have received in a poorer environment such as Britain’s. (The truth of that is rubbed in, on this very day of writing, by a new book published in Britain by the Mammal Society on its top priorities for conservation – red squirrel, hare, harvest mouse, hedgehog, wildcat, pine marten and polecat.)

  I am afraid that what I have written may sound more definitive than it really is. Taxonomy forever is in flux – written in sand, not carved in stone, and varying from source to source. What other scientific discipline has been at the same time so meticulous and yet so unreliable? For all their invisibility, golden moles are a good example, being passed like foster children from family to family. It was suggested in 1916 that they should be given an order of their own, but they were dumped instead in Insectivora – the order of insect-eaters. But diet is too loose a concept to be genealogically useful. Imagine lumping flesh-eaters together. Your Aunt Agatha would be in the same order as her cat. The whole order of insectivores, little more than a lumber-room for odd mammalian bits and bobs, was later cleared out and its denizens rehoused.

  To begin with, the bracketing of golden moles with tenrecs rested on their unpronounceable teeth. When it comes to obfuscatory language, scientists need no lessons from lawyers. In the tiny mouths of golden mole and tenrec we find a real whopper – zalambdodont. It is an adjective, and it describes their molars. From the Complete Oxford – for it’s beyond the scope of any single volume dictionary – I learn that ‘zalambdodont’ derives from the Greek words for the letter lambda and tooth, and that zalambdodont teeth have V-shaped ridges on them.

  ‘Zalambdotonty’, however, turned out to be one of those misleading physical coincidences like the elephant shrew’s nose. As Gary Bronner notes, V-ridged teeth have occurred independently in several other mammals (solenodons, for example), so it is probably explained by morphological convergence rather than by common ancestry. In a further twist, this has turned out not to matter. I won’t try to describe, or pretend to understand, how genetics confirmed what the teeth had first implied – that golden moles and tenrecs had so much shared history that they were a clade in their own right. But that is what happened. In 1999, therefore, from within the ‘superorder’ Afrotheria, the new order Afrosoricida was born – the exclusive preserve of golden moles, tenrecs and otter shrews, now out on a twig all of their own.

  Thanks to a paper by Gary Bronner, I am able to put a bit more meat on the bones. There are, he says, twenty-one known species of golden mole, all confined to sub-Saharan Africa. Despite their name (who could be surprised?), they are not all coloured gold. The family name, Chrysochloridae, derives from the Greek, ‘green-gold’, a reference to the ‘iridescent sheen of coppery gold, green, purple or bronze’ on their fur. This chimes very nicely with the ‘metallic reflections’ noted by the British Cyclopaedia of Natural History in 1836. The Victorian authors, however, had complained that a stuffed skin could give them ‘no idea of what the living animal is like’. Here Bronner is more helpful. Despite variations in size and colour, they
all look very similar. He sends me back to the dictionary to find out what ‘fusiform’ means (lozenge-shaped body tapered at both ends), but otherwise his word-picture has a Dürer-like precision. The forelegs are short and powerful with ‘pick-like’ claws. There are no external ears, eyes or tail. On the densely furred pelt, the woolly under-fur is protected by a moisture-repellent overlay of ‘guard hairs’. Beneath all this lies a thick tough skin which is particularly robust on the head, and the muzzle has a leathery nosepad to protect the nostrils. Underground the animals tunnel like machines, with upthrusts of their flattened heads and down-thrusts of the claws, leaving a ridged ‘wake’ on the surface as they go. A few of them also throw up molehills, thus adding to the confusion with the European Talpidae.

  When it comes to the exact object of my quest, however, I am hardly better off than the learned authors of the British Cyclopaedia. At least they seem to have had a skin to refer to. For the umpteenth time I turn to Alberto Simonetta’s paper of 1968. One of the most interesting things at the time seemed to be that the discovery, in the author’s own words, ‘extends by over 750 miles to the East and considerably to the North of the known range of the [golden mole] Family’. Thus it would seem to be either a known species that had gone walkabout or a new one on its own territory.

  If it was a known species, then analysis of the ear-bones would swiftly reduce the list of suspects. It hinged on the malleus, the small hammer-shaped bone that transmits vibrations from the eardrum to the middle ear. In some golden moles, I learn, this has a ‘hypertrophied ball-shaped head’. Back I go to the Complete Oxford. Hypertrophy, I discover, is the increased volume of body tissue resulting from an enlargement of the cells (as opposed to hyperplasia, which is an increased number of cells). In some other golden moles, too, the head of the malleus is ‘elongated and club-shaped’. As the pellet specimen had neither of these characteristics, it eliminated every species bar those of the genus Amblysomus. After that, it all came down to the teeth. I am really struggling now. Most of the Amblysomus species apparently have what the professor describes as ‘a more or less well developed talonid’ on their molars (dictionary again: a talonid is a flattened cusp). The specimen has no talonid at all, thus reducing the possibilities to three. After that, I confess, I am pretty much lost. My comprehension scrabbles like fingernails on rock, then slides gracelessly into the abyss. It is fashionable at the moment to talk about ‘journeys’. They are always being embarked upon in TV cookery contests or reality shows, and imply some kind of glorious ascension from darkness into light. My stubbornly unscientific brain takes me in the opposite direction. I think I understand something, then I lose my bearings in a fog of detail. So it is with the teeth. It has been a long journey indeed, from the worldwide sweep of Animalia right down to the microscopic detail of a mole’s dentition. Simonetta gives us every conceivable datum – ‘length from tip of lower jaw, teeth excluded, to occipital cordyle’, ‘breadth of ascending process’, ‘maximum breadth at tip of angular process’, ‘length of dental row at alveolar margin’, and so on. The dictionary too now rolls over and waves its legs in the air. Simonetta goes on, with ever finer detail, for twenty-eight pages, only a fraction of which I am able to follow. The shape and length of the jaw are somehow different from all previously known species – at the moment that’s all I can say. But it is enough for Alberto Simonetta to conclude that the specimen is unique. It is customary in taxonomy to name a species after its discoverer, or after someone the discoverer would like to honour. But here the commemorated hero was to be neither Simonetta himself nor any of his esteemed friends and colleagues. The honour instead would belong to the beneficent deliverer of evidence, the consumer and regurgitator of the new mole’s last remains. From the barn owl, Titus alba, sprang forth its own dedicated species, Calcochloris tytonis.

  Thus do I manage to achieve some rudimentary understanding of nomenclature and taxonomy, and of the elephant traps that await anyone with ambitions to demystify the processes of nature. Several of the species mentioned in Simonetta’s paper, including tytonis itself, have been shifted from one genus to another since its publication in 1968. Right across the tree, branches have been swishing in the storm of new evidence as species have found new relatives among the living and the fossilised dead. It’s not something that we read or hear much about – an arcane process that continues unseen in the back offices of natural history museums and makes headlines only in learned journals. I love it, though. I love the suppleness of science, its willingness to change its mind and head off in new directions. That surely is the best and most powerful validation of objective study, its great and decisive advantage over dogma. It is why Copernicus triumphed over the Church, Darwin over Wilberforce, Huxley over Owen. The more you look, the more you realise how much there is to see. A golden mole opens its mouth, and therein lie all the miracles and mysteries of creation.

  The miracles and mysteries of human civilisation, however, remain to be understood. At the end of a rain-sodden week I make another trip to London. Most of the things that can go wrong do, though I am spared a suicide. The railway line crosses the Cambridgeshire Fens, a dead-flat landscape of reclaimed seabed, scored with dykes, that a very few people love and many more find melancholic. For some, the temptation to step in front of a London-bound train is irresistible, and it is a tragically frequent cause of delay. Deliberate self-harm is another peculiarity of my own species that finds no echo in nature, though the myth of mass suicide by lemmings still persists (in reality, their deaths by drowning are the accidental results of over-ambitious sea crossings). My day requires an early start and a missed breakfast. The normally sedate forty-five-minute drive to the station is turned into a mad, heart-pumping dash by a long tailback from roadworks where 200 metres of carriageway have been coned off for the convenience of one man and a shovel. The price of my train ticket is all that you would expect from Europe’s most expensive rail network, though at least I get a seat (not a privilege available to those who board at intermediate stations). Insofar as it concerns itself with news, the paper I buy is full of grim stuff about economic crises and the moral elasticity of bankers force-feeding themselves with other people’s money. London itself does nothing to lighten my mood. If the managers of the underground system mistreated cattle in the same way as they mistreat commuters, then they would spend the rest of their lives in jail. Despite all this I arrive in good time for my meeting, but the person I am seeing is half an hour late. This delays my homeward journey until the evening rush hour, but I get to the station in good time to claim a seat on the train. Then I glance up at the platform indicator. The service has been cancelled; there has been a suicide; passengers are advised to find a different route. This means another nose-to-armpit underground crush to a different London station, then a long, roundabout crawl through rural halts that adds another two hours to my journey. For an hour and-a-half of this, I have to stand. When finally I get home, I feel a desperate need for an alcoholic drink.

  But there is something else. The red light on the telephone is blinking. A message. Wearily I tap the Play button, and there it is. A bit of fuzz and crackle; the bathroom echo of a bad line over distance. And then the voice. It is a little faint but the words, spoken with a soft Italian lilt, are as mellifluous as birdsong.

  ‘Hello,’ it says. ‘This is Professor Simonetta.’

  CHAPTER ELEVEN

  Valete Et Salvete

  Next morning I call the professor back. If he is surprised by my reverential tone – I realise I am actually bowing over the telephone – he does not reveal it. But there is a twinkle in his voice that suggests humour. He is in his eighties now but apparently still busy. Better still, he speaks good English. He listens while I pour out my story, which I tell in a confused rush with little sense of order or economy. How can I convince him that I am basing a whole book around his tiny fragment of golden mole? It must surprise him that a layman had even heard of it, let alone turned it into a quest. He chuckles. There is muc
h he could tell me, he says. Many stories. But does he have the Somali golden mole, Calcochloris tytonis, the world’s rarest known mammal? Ah! Well, of course he doesn’t have it personally . . . But why don’t I come to see him in Florence? Then he can tell me. There are so many stories . . .

  It is 9 a.m. on 22 June 2012, a date inked into my diary. We agree to meet in the third week of September. The professor will send me his address. I thank him with near-idiotic profuseness and put some champagne on ice. Florence! Venice alone might beat it as my favourite city, but it would be by only the smallest of margins. If I don’t find the mole, then at least there will be Leonardo, Michelangelo, Boticelli and rare Florentine steak. As it happens, blood, meat and mortality have been weighing heavily on my mind. An old friend has recently died and I have just returned from visiting a slaughterhouse. The two strands of thought have tangled themselves with the mole into an unpickable knot.