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Fig. 1.1 Manner of crossing the first river in Peak Cavern, engraved by Cruikshank in 1797, from G.M. Woodward’s Eccentric excursions … in different parts of England & South Wales, pub. Allen & Co., London, 1801. (Courtesy of Trevor Shaw)
Perhaps the oldest written reference to a cave appears in a book about mountains written before 221 B.C. in China – a country where caves have been systematically explored and exploited over many centuries as water supplies and as sources of nitrates for fertilizer and for making gunpowder. The earliest surviving reference to a cave in Britain dates from around 200 A.D. in the writings of Titus Flavius Clemens, known as Clement of Alexandria. He writes:
“Such as have composed histories concerning the Britannic islands tell of a cavern beneath a mountain, and at the summit of it a cleft, and of how from the wind rushing into this cavern and reverberating from its hollows, an echo as of many cymbals is heard.”
Which cave this refers to is uncertain, but a location in either the Mendip Hills or Derbyshire would seem most likely since both areas were well-known as important centres of lead mining during this period. Current opinion favours the Great Cave of Wookey Hole which would undoubtedly have been known in Roman Britain and where, according to Balch (1929), a noise like the clash of cymbals can occasionally be heard.
Irish caves were also documented from the earliest times. The Annals of the Four Masters, written in 928 A.D., record the massacre of 1000 people in Dunmore Cave in County Kilkenny and if the abundant remains excavated there are anything to go by, the account may well be true.
The myth of the ‘howling cave’ resurfaces with Henry of Huntingdon in his mediaeval Historia Anglorum, written in Latin around 1135. He gives pride of place among the four “wonders of England” to a cave “from which the winds issue with great violence”. This one appears to have been situated in the Peak District and may have been Peak Cavern, since some time later Gervase of Tilbury, writing about this cave around 1211, states that strong winds sometimes blow out of it. The third of Huntingdon’s four wonders was also a cave, this time one situated at:
“Chederole where there is a cavity under the earth which many have often entered and where, although they have traversed great expanses of earth and rivers, they could never come to the end.”
This poses modern scholars with an interesting puzzle, for although there is indeed a well-known cave at Cheddar (open to the public as ‘Gough’s Cave’), it is short, easily explored and does not connect with the underground river known to flow beneath it. However, in 1985, cave divers Rob Harper and Richard Stevenson squeezed down a narrow pit in a forgotten corner of Gough’s Cave and emerged underwater into the main river, which they followed upstream to reach a large dry cavern, dubbed the Bishop’s Palace. The flooded system lies close to the water table, and the divers surmise that before the Cheddar rising was enclosed by a dam, the water level may have been low enough to permit entry into the now-flooded cave. On the other hand, the village of Cheddar (once known as ‘Cheddrehola’) is only some ten kilometres away from Wookey Hole, and Huntingdon may well have confused the two localities.
The surprising thing is not the doubts about the accuracy of Henry of Huntingdon’s accounts, but that he should have chosen caves for two of his four ‘wonders of England’. Other mediaeval chroniclers also mention caves and mostly follow Huntingdon’s accounts closely, as also do the various manuscript ‘Wonders of Britain’ or ‘Mirabilia’ which appeared between the 13th and 15th centuries.
In the 16th and early 17th centuries writers such as Leland, Camden, Drayton and Leigh, gripped by the Elizabethan romantic passion for ‘discovering the countryside’, penned lurid accounts of the caves they visited and of the legends and folklore attached to them. One looked forward to a planned visit to Wookey Hole with not a little trepidation:
“though we entered in frolicksome and merry, yet we might return out of it Sad and Pensive, and never more be seen to Laugh whilst we lived in the world.”
The early 17th century saw the rise of a craze for so-called ‘rogue books’ – sensationalized accounts of swashbuckling anti-heroes such as highwaymen and pirates, and some of these make reference to dastardly goings-on in the caves of Derbyshire. Sam Ridd’s The Art of Juggling (1612) portrayed Peak Cavern as a notorious centre of knavery, and Ben Jonson makes several allusions to this cave (under a different name) and its association with beggars and vagabonds in The Devil is an Ass (1616) and The Gipsies Metamorphosed (1621).
Later in the 17th century the Peak District and its caves continued to attract attention through the writings of Charles Cotton, best known for his collaboration with Izaak Walton on later editions of The Compleat Angler. Cotton’s fondness for caves may be not altogether unconnected with his habit of using them as a sanctuary when hiding from his creditors.
Fig. 1.2 An imaginary ‘straightened out’ view of Peak cavern. In the foreground are the rope-makers’ cottages. From a copper engraving titled The Devil’s Arse, near Castleton, in Derbyshire which appeared in Charles Leigh The natural history of Lancashire, Cheshire and the Peak in Derbyshire, pub. Oxford, 1700. (Courtesy of Trevor Shaw)
Daniel Defoe, the great traveller and polemicist, seems to have completely failed to appreciate the ‘Wonders of the Peak’ which so enthused his contemporaries. Dubbing them the ‘wonderless wonders’, he selects Peak Cavern for a particularly scornful treatment:
“… where we come to the so famed Wonder call’d, saving our good Manners, The Devil’s A--e in the Peak; Now not withstanding the grossness of the Name given it, and that there is nothing of similitude or coherence either in Form and Figure, or any other thing between the thing signified and the thing signifying; yet we must search narrowly for any thing in it to make a Wonder, or even any thing so strange, or odd, or vulgar, as the Name would seem to import.”
This seems a bit harsh, as the entrance to Peak Cavern is, I would have thought, impressive by any standards. On the other hand, Defoe goes right over the top in his reaction to nearby Eldon Hole: “this pothole is about a mile deep … and … goes directly down perpendicular into the Earth, and perhaps to the Center”. It is actually 75 m deep.
Although Defoe’s Tour was not intended to be a guide book, a series of revisions by various editors up to 1778 made it ever more like one; even going to the lengths of adding in descriptions of caves not included in the original version. The success of the Tour and the rise of the ‘picturesque’ movement in art and architecture (epitomized by the romantic landscape designs of Humphrey Repton) no doubt encouraged the early 19th century vogue of ‘curious travellers’ who sought out and explored previously neglected corners of the countryside in order to write about their experience. Where previously the ideal landscape had been one which showed the civilizing hand of man in formal gardens and straight avenues of trees, ‘wild nature’ now became fashionable. Any accessible landscape featuring dramatic cliffs and wooded gorges, crumbling ruins and, of course, caves, became a tourist attraction. A swelling tide of visitors headed for the fashionable delights of the Peak and Wookey Hole, the scars and potholes of the Yorkshire Dales, the seacaves of Scotland and Kent’s Cavern at Torquay. Even the great Dr Samuel Johnson seems to have been caught up with enthusiasm for a sea cave he visited on Skye during his tour of the Hebrides in 1773.
The descriptions by the ‘curious travellers’ generally aimed to convey emotions of awe, wonder or terror at the beauty and power of ‘wild nature’. Caves lent themselves particularly well to the Gothic imaginations of young romantic writers like Benjamin Malkin, who described a visit to the entrance of Porthyr-Ogof in his The Scenery, Antiquities, and Biography of South Wales (1807):
Fig. 1.3 Fingal’s Cave from a hand-coloured wood engraving by Whimper, in Anon: Natural Phenomena, pub. London, SPCK, 1849. (Courtesy of Trevor Shaw)
“We penetrated about an hundred yards, as far as any glimmering of daylight from the mouth directed us: and this specimen of Stygian horror was amply sufficient to satisfy all rational curiosity. The passage over uneven rocks, with scarcely a guiding light, and in many places with a bottomless gulph directly under on the left, in a misty atmosphere from the vapour of the place and the exhaustion of a laborious walk, was not to be pleasurably continued for any length of time or distance. … Any person who will enter this cavern … may form a just idea … of the classical Avernus and poetical descent into the infernal regions.”
The north-country clergyman John Hutton stands out among the ‘curious travellers’ as someone who developed a genuine interest in caves. His A Tour to the Caves in the environs of Ingleborough and Settle (in various editions from 1780 onwards) contained descriptions of some two dozen caves and potholes and was the first book in Britain, and one of the first in the world, whose main purpose was to describe the natural history of caves. In spite of his liberal use of Gothic adjectives such as “horrid”, “dreadful” and “terrible”, a real enthusiasm for his subject comes through, and in the two later editions of his book he added a section entitled “conclusions of a philosophic nature”, in which he discusses limestone geology, cavern formation and hydrology. Some of his views, particularly those on the springs and underground streams of the area, were farsighted, although others seem laughably quaint in the light of modern science. It is interesting for the modern reader to note the touchstone against which he measured his own ideas:
“I think I may say without presumption, that my theory is conformable to events as related by Moses; and my reasoning agreeable to the philosophical principles of Sir Isaac Newton, where they could be introduced.”
The early 19th century boom in natural science, when it spread to caves, focussed initially on two fields of research which Hutton had completely overlooked – namely palaeontology and archaeology. Deposits of bones had been known from caves in mainland Europe at least as far back as the 16th century, when speculation about their nature had inclined, as might be expected, to the fantastic. Some were considered to be dragon bones, while others – the sub-fossil tusks of elephants or mammoths, known as ‘unicorn horn’ – were greatly prized for their reputed medicinal properties. Quite an industry sprang up around such deposits, and their discoverers or the owners of the caves could become rich on the proceeds.
The Victorian naturalists were the first to appreciate the antiquity of cave bone deposits and their value as a geological record of Britain’s past. The best known of the early cave excavators was Dean Buckland, who plundered cave deposits throughout the country in the 1820s. In the interpretation of his results he was limited by the thinking of his day, but he recognized that many of the bones were from animals no longer present in Britain, and in some cases from animals that no longer existed at all. He was the first to suggest that the explanation for the accumulation of fossil bones in some caves might be that in the distant past hyaenas had used the caves as dens and dragged the carcasses of animals into them. Buckland also made the first find of an Old Stone Age human burial, the ‘Red Lady of Paviland’ found in Goat Hole on the Gower coast, so-called because her body had been anointed with ochre before burial.
Fig. 1.4 Gough’s Cave digging in early 1935, first published in Bristol Evening World, 1 Feb 1935. (Trevor Shaw collection, courtesy of Cheddar Caves Ltd.)
In the 1830s, Schmerling recognized that the remains of humans and of extinct mammals found together in the same deposits in Belgium were of the same age. It was not, however, until later in the century, that the work of William Pengelly and Boyd Dawkins and their colleagues established that these remains dated back thousands of years to the Ice Ages of the Pleistocene era, when cave-dwelling people shared our familiar countryside with a fearsome array of giant animals, including cave bears, hyaenas, woolly mammoth, bison, aurochs and woolly rhinoceros. Excavation in caves has, of course, continued to the present day, and cave sites worldwide have now yielded material which has helped to shape our understanding of human evolution and the birth of our culture.
The sporting science (#ulink_f41c1779-df4f-5cd0-b9a8-6150636b32de)
The systematic exploration, documentation and commercial exploitation of caves was already underway in China many centuries before miners and natural historians first began to measure and record details of our European cave systems in a scientific way. One of the first of this breed of explorers in Britain was John Beaumont, a 17th century Somerset surgeon and an amateur student of mining and geology. When in 1674 lead miners excavating a shaft in the Mendip Hills accidentally breached a natural underground chamber, Beaumont hastened to the site and hired six miners to accompany him into the cave. Carrying candles, the company descended the 18 m shaft to the first chamber, which Beaumont proceeded to measure: it was 73 m long, two metres wide and nine metres high. “The floor of it is full of loose rocks,” wrote Beaumont in his subsequent report to the Royal Society, “its roof is firmly vaulted with limestone rocks, having flowers of all colours hanging from them which present a most beautiful object to the eye.” The intrepid surgeon then led a 100 m crawl through a further low passage which opened into the side of a second chamber, so vast, Beaumont reported, that “by the light of our candles we could not fully discern the roof, floor, nor sides of it.” The miners, accustomed as they were to the underground, could not be persuaded to enter this chasm, even for double pay. So Beaumont went down himself:
Fig. 1.5 Interior Chamber of Cox’s Stalactite Cavern, Cheddar, Somersetshire. Lithograph by Newman & Co. London; pub. S. Cox, Cheddar about 1850. (Courtesy of Trevor Shaw)
“I fastened a cord about me, and ordered them to let me down gently. But being down about two fathom I found the rocks to bear away, so that I could touch nothing to guide myself by, and the rope began to turn round very fast, whereupon I ordered the miners to let me down as quick as they could.”
He landed dizzy but safe 21 m below, on the floor of a cavern 35 m in diameter and nearly 37 m high within which he found large veins of lead ore. Surprisingly, Beaumont’s account failed to stimulate much curiosity about caves in scientific circles, and after a brief flurry of lead mining, the cave, known as Lamb Leer, was abandoned; its entrance shaft eventually collapsed and the sealed-off chamber was virtually forgotten for two centuries.
The rediscovery of Beaumont’s long-lost Lamb Leer cave took place in 1879, the same year that a young French law student, Edouard-Alfred Martel, made his first visit to the famous Adelsberg Cave in Slovenia (which was then part of Austria, but since World War II has reverted to its local name of Postojna Jama). Martel was completely enthralled, and in 1883 began to devote all his vacation time to cave explorations in the Causses of southwestern France. What set him apart from previous cave explorers, was his meticulous preparations and his systematic recording of all aspects of the caves he explored, combined with a tremendous physical ability and courage. His speciality was deep vertical pits, and in 1889 he successfully negotiated the 213 m vertical entrance shaft of the Rabanel pothole north-west of Marseilles – an outstanding feat given the equipment then available.
To calculate a pit’s depth, he would read the barometric pressure at the bottom and compare it with the surface pressure. He measured the horizontal dimensions of each newly-discovered chamber with a metal tape, drawing a sketch of the cave as he worked. Roof heights were calculated with an ingenious contraption: after attaching a silk thread to a small paper balloon, he would suspend an alcohol-soaked sponge beneath it, light the sponge, and measure off the length of thread carried aloft by the miniature hot-air balloon. Martel also habitually recorded subterranean air and water temperatures, finding variations with depth and season, and amassed whole volumes about cave geology, hydrology, meteorology and flora and fauna. But perhaps his greatest contribution to cave science was his research on how subterranean water circulates – a study prompted by his own bout with ptomaine poisoning, contracted from drinking spring water in 1891. After recovering from the illness, he traced the spring’s source using fluorescein dye introduced to nearby sink holes. Descending the appropriate pit, he found the putrefying carcass of a dead calf that had contaminated the spring with what he wryly termed “veal bouillon”. Further study allowed him to distinguish between “true springs”, fed by diffuse circulation of rainwater, cleaned and filtered by its passage through soil and rocks, and “false springs” fed by a rapid flow from sinkholes via cave passages too large to filter out impurities. Martel’s subsequent campaigning for stricter control of sources of drinking water eventually led to a dramatic reduction in deaths from typhoid and won him a gold medal from the French Government.
In 1895 Martel founded the French ‘Société de Spéléologie’, arguing that ‘speleology’, which had been previously considered a sport or a singular eccentricity, should be recognized as a fully-fledged science – “a subdivision of physical geography, like limnology for lakes and oceanography for seas.” A prolific author, he edited Spelunca, his Society’s bulletin, and wrote books about his own cave discoveries. In 1907 the French Academy of Sciences awarded him the grand prize for physical sciences, and in 1928 he was elected president of the Geographical Society of Paris. By the time he died in 1938, aged 78, the grand old man of speleology had personally probed nearly 1500 caves, hundreds of which had never been entered before; his technical innovations had become standard equipment for other cavers; and above all, his persistence and dedication had created a framework within which the seedling science of speleology could develop and blossom.
Meanwhile, the systematic documentation of caves had also started in Britain, with the formation of the Yorkshire Ramblers’ Club in 1892. Under the influence of S.W. Cuttriss, dubbed ‘the scientist’ for his assiduity in recording the group’s findings, its members drew up surveys of the caves they explored, and kept notes of temperatures, altitudes and geographical features.
The great exploration challenge of the day was the awesome Gaping Gill, a pothole high on the slopes of Ingleborough Hill which had been plumbed to a depth of 110 m, but had never been descended. The main obstacle to its exploration came from Fell Beck, an icy stream which cascades down the entrance, filling it with spray and extinguishing any flame which might light a caver’s descent, as well as half-drowning him. A local man, John Birkbeck, had made two heroic, but unsuccessful attempts to descend the pit in the 1840s, after digging a trench to divert the Fell Beck to another sink. His first try nearly proved fatal, when strands of his rope were severed on a rock ledge, but on his second attempt he reached a ledge at 58 m which now bears his name. Yorkshire Ramblers’ member Edward Calvert took up the challenge and had almost completed his own preparations for a descent on rope ladders in 1895, when Martel arrived on the scene, hot-foot from London where he had been invited to address an International Geographical Congress on cave-hunting methods.
As something of a celebrity, Martel was encouraged by the lord of Ingleborough Manor to have a crack at the great pothole and given the support needed to refurbish and extend Birkbeck’s trench. On August 1, before an eager crowd, Martel knotted together his lengths of ladder and lowered them into the darkness. As he climbed down the four metre-wide shaft he was rapidly enveloped by “half-suffocating whirls of air and water” which soaked his clothes and the field telephone which he relied upon to communicate instructions to the back-up team who controlled his safety line from the surface. The cascade redoubled 40 m down and he had to descend through a “frigid torrent gushing from a large fissure”. Pausing on Birkbeck’s ledge to untangle the huge heap of rope which had lodged there, he continued into the unknown depths below. Sixteen metres on, the walls of the shaft suddenly receded and Martel found himself swinging like a pendulum near the roof of an immense chamber nearly 160 m long by 30 m high. He alighted on the floor only 23 minutes after he began the descent, and characteristically at once set about measuring and sketching his discovery. For an hour and a quarter, the Frenchman revelled in the spectacle of the “Hall of the Winds”, Britain’s largest underground chamber from whose roof the waters of the Fell Beck tumbled “in a great nimbus of vapour and light”. There was a certain sense of nationalist triumph too: “The most pleasant feature was the thought that I had succeeded where the English had failed, and on their own ground.”
Fig. 1.6 Gaping Gill – the main chamber showing the waterfall falling 110 metres from the surface. A photograph taken in the 1930s by Eli Simpson. (Trevor Shaw collection)
Martel’s descent of Gaping Gill received wide publicity and awakened an interest in the possibilities of cave exploration in other parts of Britain. A group of Derbyshire rock climbers calling themselves the Kyndwr Club started to explore the caves of that county and further afield. One of their leading spirits was Dr E.A. Baker, a native of Somerset, but at that time resident in the Midlands. He was a colourful and influential character, an academic who later became director of the School of Librarianship in the University of London, but whose interest in caving was primarily sporting.
At about this time, H.E. Balch, a young postal worker at Wells in Somerset, came across a fragment of reindeer antler in the Hyena Den near Wookey Hole and, inspired by the work of Professor (later Sir William) Boyd Dawkins, at once threw himself into a study of all kinds of archaeological and fossil cave sites on Mendip. Soon Balch had founded the Wells Natural History and Archaeological Society and started the collections which eventually grew into Wells Museum. The subsequent arrival on the Mendip scene in 1902 of Baker and his colleagues from Derbyshire led to a long and fruitful collaboration, during which many of Mendip’s greatest caves were dug open and explored. Both Balch and Baker were prolific writers and their publications, spread over several decades, played a large part in stimulating an interest in caving during the early part of this century. A number of clubs began to appear which cheerfully combined a scientific and sporting approach to caving, setting a pattern which has continued to the present day. Scientifically motivated ‘speleologists’ still recognize their dependence on sporting cavers for much of the initial exploration and often for support when working in the more exacting situations. Many are in any case themselves sporting cavers, or were in their younger days. On the other side very few of those whose motives are primarily sporting are completely uninterested in the whys and wherefores of the natural features which provide them with their sport. They also appreciate that scientific understanding increases the chances of finding more caves.
There are few completely unexplored places anywhere on the surface of the earth and none in a country such as Britain; but caves hold out the promise, or at least the hope, of completely new discovery. Most cavers must sometimes dream of one day discovering a new cave, or an extension to a known one, and of being the first to gaze upon whatever wonders it may hold. If these are the things which provide motivation for caving as a sport, they are nearly always reinforced by at least some measure of scientific curiosity, and most cavers combine the two in varying proportions.
In the years after World War II, the popularity of caving, as of so many other active pursuits, increased enormously in many parts of the world. In Britain the 1950s and 60s in particular saw a great proliferation of caving clubs and, although some of these were ephemeral, the overall level of interest and activity has remained high. Perhaps the most important development in British caving in the early post-war years was the opening up of South Wales as a major caving region. Up until 1936, cavers had taken surprisingly little interest in the area considering that Porth-yr-Ogof had been known for hundreds of years and Dan-yr-Ogof had been discovered and explored as far as the waterfalls in 1912. It was to these two caves that experienced cavers from Yorkshire and Mendip first turned their attention in 1936 and interest in the area developed rapidly. By the time that caving came to a virtual halt with the outbreak of war in 1939, the potential of South Wales was apparent to all. In 1946 the South Wales Caving Club was formed and within a few months two of its members, Peter Harvey and Ian Nixon, dug their way into the lower end of the great Ogof Ffynnon Ddu cave system on the east side of the Upper Tawe Valley. Initially rapid exploration was halted by a series of sumps (flooded sections of passage) and it was not until 1966 that a dig in the upper levels of the cave gave access into the vast maze of OFD II. A rush of new discoveries followed in quick succession over the next year, extending the vertical range of the cave to 300 m and its total length to around 40 km, making it Britain’s deepest and longest cave system. (Although cave divers have since linked up various parts of the Ease Gill system in Yorkshire to give it the number one position with an overall passage length of over 70 km).
As we have seen, cave science, and in particular the archaeological and palaeontological investigation of caves, started well before the development of caving as a sport. As early as the mid-nineteenth century the living faunas of caves were receiving fairly extensive study in mainland Europe and America by the likes of J.C. Schiodte and A.S. Packard; and following the influence of Martel, the physical aspects of speleology – geology, geomorphology and hydrology – were well established there by the turn of the century.
Underground naturalists (#ulink_b63e7cbc-aa70-537f-b28b-9dda4a7675f9)
Evidence that early man was conscious of the existence of a subterranean fauna dates back to a remarkable engraving of a cave cricket on a bison bone discovered by Count Begouen while excavating in the Grotte des Trois Frères in the French Pyrenees. The carving is believed to be 18,000 years old, yet is sufficiently clear and detailed for the subject to be recognizeable as a Troglophilus species, which today is distributed from Italy to Asia Minor, but no longer inhabits France.
For the next surviving reference to cave life in Europe, we must move on to the 16th century and the observant Count Trissino, who, in a letter dated 5th March 1537, recorded what must have been a form of the cave-limited amphipod, Niphargus. He noted that at the far end of the Covolo di Costozza in northern Italy there was a deep pool of clear water. “In this water no fish of any kind are found, except for some tiny shrimp-like creatures similar to the marine shrimps that are sold in Venice.”
Fig. 1.7 A prehistoric engraving on a bison bone, discovered by Count Bégouen in the Grotte des Trois Frères (French Pyrenees), featuring the cave cricket Troglophilus. (After Bégouen)
The Slovenian Olm, Proteus, seems to have been well-known to the villagers of the Trieste area for centuries. Specimens occasionally appeared after floods in the Lintverm (from the German ‘Lindvurm’, meaning ‘dragon’) – a tributary of the River Bela near Vrihnika. With their long, pink, rather reptilian bodies, they were taken, not unreasonably, to be dragon fry – the offspring of a shadowy monster who lived in the roaring cave from which the river flowed and who caused periodic floods by opening sluice gates when her living quarters were threatened by rising water. But in the 1680s, Baron Johann Valvasor, a Slovene nobleman and well-travelled amateur scientist, ruined centuries of colourful legend by exposing the Olm as a perfectly natural blind cave salamander.
In 1799, the German naturalist-explorer Baron Alexander von Humboldt, accompanied by a French botanist called Bonpland, visited the famous Cueva del Guacharo in the Caripe Valley of Venezuela. There he collected and described a cavernicolous bird, Steatornis caripensis, belonging to the order which includes the nightjars, which had been known for a long time to the Indians under the name ‘guacharo’. Humboldt was greatly impressed by the screeches produced by the birds when disturbed at their cave roost. “Their shrill and piercing cries strike upon the rocky vaults,” he wrote, “and are repeated by the subterranean echoes.” Having heard them myself, I would describe the racket as the sound of a thousand mad chickens locked up in a barn with a fox.
In 1808, Schreibers discovered the first invertebrate cave fauna in Austria and more extensive collecting was done in the Postojna area by Count Franz von Hohenwart and others from 1831 onwards. It was there too that the Danish zoologist J.C. Schiodte recognized that cave faunas showed differing degrees of specialization to life in darkness, and so laid the foundations for a system of ecological classification of cave life. This was advanced in a more rigorous form in 1854 by J.R. Schiner and has been widely used by cave biologists ever since. This work perhaps marked the beginnings of the systematic discipline of ‘biospȼologie’, a term proposed by Armand Viré in 1904, to refer to the study of subterranean life.
Fig. 1.8 The old route across the underground river Pivka in the Great Hall of Postojna Jama in Slovenia from an aquatint engraved by G. Dobler after a painting by Alois Schaffenrath, published in 1830. (Courtesy of Trevor Shaw)
In the USA important work continued intermittently from 1840. In that year Davidson collected the first specimens of a blind white fish in Mammoth Cave, described by de Kay, Wyman and Tellkampf as Amblyopsis spelaea. Tellkampf went on to describe other fauna from Mammoth Cave and was followed by E.D. Cope and A.S. Packard, whose remarkable studies through the 1870s put America for a time at the forefront of biospeleological research. Meanwhile, in the 1840s, V. Motschoulsky reported the first cave-specialized insects captured in the caves of Caucasia, and in 1857 De la Rouzee discovered the first cavernicolous insects known from France.
Scientific investigation of our cave faunas began in a round-about way in about 1852, when Professor Westwood and S. Bate included the following reference in their History of the British Sessile-eyed Crustacea, Vol.1, published in 1863.
“In the year 1852”, writes Bate, “Professor Westwood was so fortunate as to obtain from a pump-well near Maidenhead, a quantity of [Niphargus sp.] … since when they have been found in Hampshire, Wiltshire … and very recently in Dublin.”
Shortly afterwards, news of the discovery in Europe and America of strange blind cave animals prompted Naturalists E. Percival Wright and A.H. Haliday to search for similar creatures in Mitchelstown New Cave in Co. Tipperary. Their search was successful and they described their find – a tiny Collembolan doubtfully identified as Lipura stillicidii Schiodte – in a paper read before a British Association Meeting in Dublin in 1857.
More than thirty years were to elapse before the next glimmer of enthusiasm for Irish cave life manifested itself in the form of a joint excursion in 1894 by the Dublin, Cork and Limerick Field Clubs to the Cave of Mitchelstown. One of the participants, George H. Carpenter, recorded that “after an informal luncheon on the roadside, the party being provided with candles, descended the sloping passage and ladder which led to the depths below.” They spent two hours searching for cave animals and, although they failed to reach the underground river, made a reasonable collection of fauna, including the rare blind cave spider now known as Porrhomma rosenhaueri. In the same year, pioneering English arachnologist F.O.P. Cambridge collected spiders in Wookey Hole, but without finding anything of particular interest.
Early in 1895 E.A. Martel and his wife paid a well-publicised visit to Ireland. The event prompted the Fauna and Flora Committee of the Royal Irish Academy to support H.L. Jameson with a grant “to further investigate cave fauna in Ireland”. He joined the Martels in the Enniskillen area of Co. Fermanagh and, while the Frenchman surveyed the caves and drew up his plans, Jameson collected cave animals. The interest seems to have persisted, for Jameson is also known to have made faunal collections in Speedwell Mine in Derbyshire in 1901, but there then followed a gap of over thirty years during which British cave fauna was again neglected.
Fig. 1.9 One of the earliest illustrations of cave fauna from Adolf Schmidl’s Die Grotten und Höhlen von Adelsberg, Lueg, Planina und Laas. Wien, Braumüller, 1854. (Courtesy Trevor Shaw)
In 1936 the British Speleological Association was launched, with a brief to co-ordinate the work of caving clubs and to foster interest in the scientific aspects of caving. Things did not run entirely smoothly, however, and in 1947 another body, the Cave Research Group of Great Britain, emerged with a more specific research interest. Both societies ran in parallel until 1973 when they merged to form the British Cave Research Association which has become a major publisher of speleological research.
Meanwhile another organization concerned with cave science had been formed in 1962. This was the Association of the Pengelly Cave Research Centre, now the William Pengelly Cave Studies Trust. It is London-based, but its interests are very much centred in Devon where it runs the Pengelly Cave Research Centre at Buckfastleigh. The trust is active in education and conservation and produces publications covering a broad range of speleological topics.
The multidisciplinary nature of speleology allows significant contributions to be made as much by talented amateur observers as by trained professional scientists, and we owe much of our present knowledge of the faunas of British caves to the work of a handful of exceptionally dedicated amateur naturalists. The central figures of the group were Brigadier E.A. (Aubrey) Glennie and his niece Mary Hazelton, who in 1938 began making systematic collections in the caves of Yorkshire, Derbyshire and Mendip. Glennie, an excellent all-round naturalist, picked up his interest in cave life while serving in India, where among other things, he published a study on the nesting behaviour of Himalayan Swiftlets in caves. On his retirement in 1946, he became a driving force in the biological work of the newly formed Cave Research Group, and was soon recognized as an authority on British hypogean amphipods. Hazelton assumed the mantle of Biological Recorder to the CRG, and for the next 29 years diligently co-ordinated the identification of collections submitted by fellow cavers and compiled the results for publication, first in the Transactions of the Cave Research Group and later of the British Cave Research Association. Among the most notable contributors to the faunal collections of this period were Jean Dixon of the Northern Cavern & Mine Research Society and W.G.R. Maxwell of Chelsea Speleological Society.
The 1950s saw the appearance on the scene of two particularly influential figures, both professional biologists. One was Dr Anne Mason-Williams, a microbiologist whose pioneering studies on the microflora of South Wales caves remains the definitive work in this field. The other was Dr G.T. ‘Jeff’ Jefferson, a lecturer in zoology at University College, Cardiff, who quickly established himself as the leading authority on British cave faunas and went on to become president of the British Cave Research Association, and a greatly respected ambassador for speleology in Britain. Jefferson’s major contribution to cave science in Britain before his untimely death in 1986, was in shaping the wealth of observation gathered by his amateur predecessors into a coherent picture of the biogeographical history and ecological relationships of our cave fauna. It is his work above all that has provided the inspiration for this book.
Non-cavers are fond of asking cavers why they venture underground. The usual answer is along the lines that “caving is good fun”. Many would add that caving is most fun when spiced with the excitement of discovery. For the sporting caver, this means finding a way into previously unvisited passages, or whole new cave systems. For the speleologist there is the further excitement of recording new observations and of gaining fresh insights into the history, development, or life of the cave. The discipline of cave biology remains poorly developed in Britain and Ireland, affording tremendous scope for discoveries of all sorts by amateur as well as professional naturalists.
Driving curiosity and a sense of wonder are perhaps the two features which above all unite the caver and the naturalist. I hope that this book can make the passion of the one intelligible to the other, and so enhance the experience of both.
2 (#ulink_ddade697-6b84-5186-a513-b28690015f02)
The Cave Habitat (#ulink_ddade697-6b84-5186-a513-b28690015f02)
What is a cave? (#ulink_1379e1f4-d066-5f92-9144-9db416f81157)
Put this question to any wetsuit-clad, hard-hatted individual found walking across the Mendip Hills, Yorkshire Dales or the shining limestone pavements of the Burren, and you will discover that a cave is a naturally-formed hole in limestone which is large enough to be explored by a caver.
Ask the same caver what he or she has noticed in the way of living creatures in caves, and the answer may well be “not a lot.” It will perhaps surprise most cavers (and naturalists) to learn that over a hundred species of invertebrate animal have been recorded as maintaining permanent populations in cave habitats in Britain and Ireland, plus another score or so species of creatures such as bats and moths which use caves as a regular part-time shelter. The cryptic community to which these creatures belong remains largely undetected by cavers because it generally avoids the relatively large tunnels and booming chambers, the glistening calcite draperies and crashing waterfalls which so captivate the human cave enthusiast, preferring instead the cosy confines of smaller cracks and crevices. I hope in this book to shed light on at least a portion of this unsuspected world which lies beneath our feet, whether we live in Grassington or Glasgow, Lisdoonvarna or London, and to offer pointers to fellow amateur naturalists towards fruitful areas of investigation for the future.
To unravel the natural history of a cave, or indeed any habitat, we must try to perceive it as far as possible from the point of view of its inhabitants. It requires a considerable effort of imagination for such sight-dependent creatures as ourselves to grasp the essence of life in the dark and labyrinthine realm of the cavernicole. A little inspired speculation may be needed to find the ‘right’ questions to lead us to fresh insights into the mysterious world beneath us.
We might start by imagining what kinds of habitats could be accessible to the cavernicole and then consider which environmental characteristics of such places are likely to influence its choice of where to live. Almost at once we run into problems, for although a good deal is known about the environment in man-sized, air-filled limestone caves in Britain and Ireland, we know much less about the conditions within smaller cracks and crevices or in caves beneath the water-table, and less still about our submarine caves. Fortunately, such information is more readily available from other parts of the world. So in this chapter we will take an international approach to defining and classifying the cave environment, before turning in later chapters to a detailed consideration of what is known about our own cave fauna.
What then is a ‘cave’ as perceived by its inhabitants? The dictionary definition of “a natural underground chamber” gives us a less than helpful starting point, for why should we suppose that the cavernicole will distinguish between natural or man-made tunnels, or between subterranean and above-ground enclosed chambers, as long as the appropriate conditions of food supply and microclimate are present in the living space? Should we then include mines, adits, buried pipes, culverts, sewers, cellars, tombs, the London Underground System, or perhaps even houses and other enclosed buildings in our preliminary list of potential cave-habitats? To what extent should our definition specify the material bounding the cavity? Must a cave be rock-lined, or should we widen our brief to include animal burrows and other spaces present in soil, for surely it must be arbitrary to distinguish between an earthy burrow and a muddy hole of similar dimensions in rock?
Fig. 2.1 The main tunnel of Sleets Gill Cave in Wharfedale, Yorkshire Pennines – a classic phreatic tube, formed and enlarged by water filling the passage and so dissolving the limestone rock equally on all sides. (Chris Howes)
As it happens, soil faunas are very well documented, and while it seems that many animal groups are common to both soils and caves (and indeed to leaf-litter and the deep moss-carpets of tropical regions as well), the fauna of organically-rich topsoils is sufficiently distinct from that of most rock-space habitats to warrant a separate treatment. I shall therefore exclude soils forthwith from our definition of cave habitats (but see ‘Cave sediments’ under ‘Types of cave habitat (#ulink_5bea4dd5-a385-536b-ad66-50d8d314cfdb)’ later in this chapter). Similarly, the voids in other organic, living or once-living materials, such as wood or the guts or blood vessels of animals, have distinctive specialized faunas of their own, clearly distinguishable from those of habitats within inorganic materials – although some specialized xylophages, such as termites, and endoparasites, such as tapeworms or flukes, share certain morphological specializations (eyelessness, depigmentation) characteristic of the more specialized cavernicoles. When it comes to holes of human fabrication, most significant biological criteria must lead us to include them in our category of caves. That they have a very poor fauna in comparison with natural caves, is due less to their artificial nature than to their frequent isolation from sources of natural colonization and their often unfavourable microclimate.
Having narrowed our definition of the cave environment to ‘habitable voids bounded by walls of rock, or similar inorganic materials’, let us now consider the physical criteria which may determine their habitability: the presence or absence of light, physical space (the size of the hole), the medium filling the space (water or gas mix), the microclimate within the medium (the pattern of change in temperature, pH, etc. over time), and the nature and amount of available food.
Let us begin with the business of light, a variable of obvious biological significance. Beyond the limits of light penetration, the cavernicole will be obliged to rely on senses other than sight, and on foods other than green plants. Perpetual darkness is a characteristic of most rock void habitats anyway, so let us choose to define ‘the cave’ as a habitat entirely without natural illumination. This will substantially simplify our task, by excluding from the cave fauna a whole host of organisms which seek shelter in cave entrances, but also live in a wide range of other shady, sheltered habitats such as the woodland floor, or river gorges, or houses and other structures used by people. Later we will consider the illuminated portions of man-sized caves as a significant ‘cave-related habitat’ – the ‘cave threshold’ – simply because it is familiar and accessible to cavers, while ignoring all other lit, cave-related habitats.
In the world of dark holes, the physical dimensions of a potential habitat are of obvious importance in determining what creatures can colonize it. One has only to consider the relative body-diameters of a man (say 450 mm across the shoulders), a Greater Horseshoe Bat (60 mm), a cave spider such as Meta menardi (6 mm), a springtail (0.6 mm) or a nematode worm (0.06 mm) to appreciate that one creature’s spacious accommodation may be another’s unenterable squeeze, and that the cave biologist may be excluded physically from all but a tiny proportion of the very largest of cave habitats. Frank Howarth, an entomologist who works mainly on the fauna of Hawaiian lava caves, distinguishes three principal hole-size categories which appear to have biological significance for subterranean biotas. He terms these ‘macrocavernous’ (>200 mm diameter), ‘mesocavernous’ (1–200 mm diameter) and ‘microcavernous’ (<1mm diameter).
The characteristic inhabitants of Howarth’s microcaverns are sometimes termed ‘the interstitial fauna’. They include a distinctive suite of specialized, skinny-bodied crustacea (such as Bathynella and various harpacticoid copepods) and other tiny creatures (such as rotifers, nematodes and tardigrades) which mostly like to be in contact with a solid surface on all sides and typically inhabit the spaces in between unconsolidated, fine-grained sediments such as the sand and gravel of river beds and the seashore. I propose, on purely arbitrary grounds, to exclude this fauna from further discussion in this book (except for species which also frequently inhabit larger spaces), and to restrict the definition of the cave habitat to holes of 1 mm diameter upwards, that is, to mesocavernous and macrocavernous habitats.
Various vertebrates use macrocavernous caves (and the larger mesocaverns) for shelter and they, and the other species which depend on their presence, form characteristic communities which reach astonishing levels of diversity and abundance in tropical regions. I shall long remember my first visit to the spectacular Deer Cave in the Gunung Mulu National Park in Sarawak, where at dusk close on half a million bats stream out of the cave in a seemingly-endless cloud which winds its way across the sky with a rush of wings like the sound of Niagara Falls. British bat-watchers have to be content with the odd flap, but in spite of declining populations, cave-roosting bats are still widespread and bat caves do support their own suite of associated ‘batellite’ cavernicoles. Other cavernicoles may, for example, be specifically associated with the guano of cave-roosting crickets, or with cave sediments introduced by sinking streams.
Mesocavern-sized holes not only occur within karstic rocks, but also in screes, in the coarse gravels and rocky beds of upland rivers, between the pebbles and cobbles of exposed sea-shores, in the fractured zone of non-karstic rocks (especially shales) just beneath the soil, and as cooling cracks in lava flows and other igneous rocks. They represent a very much larger habitable subterranean space than do macrocaverns and so have developed a richer and often more specialized fauna, frequently dominated by species peculiar to this habitat and characterized by a reduction in the size of the eyes, loss of pigment and various other specializations. These ‘mesocavernicoles’ may also occur in soil spaces, or animal burrows, or even in large macrocaverns, provided there is an adequate food supply of down-washed organic material and a fairly stable humid microclimate. Not all species within the mesocavernous fauna will be found in all related habitats; some do not seem to occur in soil-spaces, others shun human-sized caves.
Simply as a consequence of our own species’ enormous body-size, we are physically excluded from the very habitats which are most likely to harbour a specialized fauna. In the absence of appropriate tools with which to peer inside mesocavernous habitats, cave biologists have so far been forced to infer what they can about them from the behaviour of their biotas where they pop up in the accessible portions of people-sized caves. These act as windows into the mesocavernous world, but it seems likely that they provide a distorted view, encouraging widely differing interpretations of the nature of what has been observed. The present situation in cave biology is a bit like that which prevailed among astronomers a century or so ago, when dependence on inadequate earth-based optical telescopes sustained the widely-held belief that Mars was criss-crossed by an elaborate network of irrigation canals built by Martians. Speculation and controversy abound no less in cave biology literature, while cavernicolous communities remain enigmatic and under-recorded. As a result, new species await discovery in most subterranean habitats in every part of the world including the British Isles. In short the whole subject of cave biology is very much still in its infancy. A nice illustration of this turned up on my desk in the form of a report from Frank Howarth, announcing his discovery of a brand-new diverse fauna of highly specialized cavernicoles in lava caves in tropical Australia. For years Australia was thought to have a very poor fauna of specialized cavernicoles, and a number of papers sought to explain this on theoretical grounds. For example, it was argued that Australia’s climate during the Pleistocene had not been harsh enough to exterminate the above-ground populations of its cavernicoles, and so any tendency on their part towards specialization for underground life would be continually cancelled out by gene flow from outside the cave. Having wickedly sub-titled his paper Why there are so many troglobites [= highly specialized cavernicoles] in Australia, Howarth makes the telling point that “One has to actually enter a cave and look for troglobites before proclaiming on theoretical grounds that none could exist.” I offer this creed to the reader in the context of the British cave fauna. Let us, as naturalists, devise ways to find out what lives in our underground world and get down and study it at first hand.
I have distinguished between ‘interstitial’ (microcavernous) and ‘cave’ (meso- and macrocavernous) habitats on the grounds that their biotas are substantially distinct. We might expect a similar distinction to exist between ‘aquatic’ and ‘terrestrial’ cave communities. Certainly, there are some cavernicoles which are essentially aquatic, and others which are essentially terrestrial. However, the atmospheres of most mesocavernous, and of some macrocavernous, gas-filled habitats are permanently saturated with water vapour. This poses physiological problems for many groups of terrestrial arthropods which, unless equipped to eliminate excess water from their tissues (as aquatic species do), would quickly die of ‘water poisoning’ through dilution of their body fluids. Not surprisingly, ‘terrestrial’ mesocavernicoles have been found to be physiologically specialized to cope with a hydrating atmosphere and seem able to withstand long periods of immersion in freshwater – an adaptation which is essential in habitats which are frequently flooded by downward-percolating rainwater or by fluctuations in the water-table. Some seem equally at home in air or water, and can frequently be seen feeding on the floor of cave pools among their aquatic counterparts. Conversely, many freshwater aquatic mesocavernicoles seem able to cope with ‘terrestrial’ life without undue physiological stress and have been recorded as living out of water for several weeks at a time. So we see that the distinction between terrestrial and freshwater aquatic cave habitats is not exactly cut-and-dried, although there is a clear distinction between the communities present in either zone and those found in marine cave habitats.
Not all terrestrial cave habitats are moist. Large caves with more than one entrance often experience drying airflows which can produce desert-like conditions which are lethal to the hygrophilic denizens of the mesocaverns. However, such caves are often easily accessible and attractive to vertebrates, and may (especially in the tropics) support vast populations of bats, birds and guano-associated invertebrates. Guanobious animals exhibit few or none of the morphological characteristics considered by European cave biologists to be the mark of a ‘true cavernicole’ or ‘troglobite’, yet they may be just as exclusively cave-dwelling as any mesocavern specialist. Above-ground human structures are usually designed to be as dry as possible and are seldom completely dark, and this makes them suitable as a habitat for only a very few cave-threshold specialists, such as the daddy long-legs spider Pholcus phalangioides which presumably originated somewhere in the Mediterranean region, but in the UK is found only in houses. In between the dry, draughty macrocaverns and the soggy, airless mesocaverns, there may be wide expanses of transitional cave habitats with a variable microclimate, posing a distinct set of problems for the communities which inhabit them. Terrestrial inhabitants of such places must cope with the physiological stress of desiccation some of the time and physiological drowning for the rest of the time. In the tropics, transitional cave habitats may be particularly extensive, with their own specialized faunas, often dominated by ‘bandits’ – marauding predators and scavengers which live off the scraps of the guano-based community. Climatically similar conditions are found in man-made culverts and other artificial tunnels, and these frequently attract transitional-zone cavernicoles such as the widely distributed cave spider Meta menardi. Later we shall distinguish a range of natural and artificial cave habitats principally on the basis of their microclimatic regimes.
In earlier discussing the criteria which may be important to cavernicoles in choosing their habitats, I included the apparently pedantic phrase ‘gas mix’, rather than ‘air’ in my list of the media which may fill mesocavernous voids. I did so because it seems that the atmosphere of mesocaverns may differ substantially from that found in open macrocaverns with a good air circulation (which generally have much the same atmosphere as the outside world). Bacterial decomposition of organic material in small spaces frequently results in unusually high atmospheric concentrations of carbon dioxide. Frank Howarth’s new Australian cavernicoles, mentioned earlier, were found in poorly ventilated lava caves which are thought to share the atmosphere of the mesocavernous spaces in the surrounding basalt. The air in these caves is saturated with water vapour and contains around 250 times more carbon dioxide than normal air. Bad air caves occur in Britain too, but have not yet been biologically investigated.
Finally, we may seek to distinguish cave habitats from non-cave habitats in terms of their food supply. Early cave biologists, whose experience of cave faunas was mainly confined to the larger, more easily explored ‘fossil’ macrocaverns (those no longer bearing the watercourses which formed them) of temperate European limestone areas, concluded that cave animals were perpetually starved. While food resources may be very thinly distributed in such cave habitats, in others (and particularly in the tropics) food may be superabundant. The biotas of food-poor caves are adapted to eke out what little energy is available, while those of food-rich caves are adapted to a life of plenty. Caves may contain a wide range of food sources, including living vegetation (tree roots, saprophytic plants and fungi which get their energy by digesting organic matter rather than by trapping sunlight, fruits carried in by vertebrates), living invertebrate or vertebrate animals, and all kinds of detritus. Cavernicoles may be plant-, fungus-, detritus- or bacteria-feeders, predators, parasites or a combination of these. In short, caves are more ecologically diverse than most biologists realize.
To summarize then, cave habitats may be defined as ‘perpetually-dark voids, more than one millimetre in diameter (and sometimes much larger), bounded by rock or similar inorganic materials, and filled with gas (‘fresh’ or ‘bad’ air) and fresh or salt water.’ Within such habitats, the microclimatic regime and the type and quantity of the available food-supply largely determines the species composition of the cave community. Only the largest (and often, in our islands, the least populated) cave habitats are accessible to human observers, so that we know a good deal less about the composition and functioning of cave communities in Britain and Ireland than we do about most other natural communities of our islands.
What lives in caves? (#ulink_d43cd1d6-64b1-56ff-a027-06d7ca0deb50)
Of the voluminous literature dealing with the biota of caves, two works of this century stand out for sheer scope of vision. The first, B. Wolf’s Animalium Cavernarum Catalogus, published in three parts between 1934 and 1938, lists all animal species recorded from caves to that date. The second, by A. Vandel, published in French in 1964, discusses the biota and biology of caves worldwide. An English translation, published by Pergamon Press in 1965 as Biospeleology: The Biology of Cavernicolous Animals, is perhaps still the most useful general text despite its wacky view of evolution in caves. L. Botosaneanu’s book Stygofauna Mundi, published in 1986, gives a more up-to-date account of the fauna of subterranean waters, but there is need for a similar treatment of the terrestrial cave fauna to take into account the spate of biological discoveries in tropical caves during the decade and a half since Vandel’s book. The following brief summary illustrates the range of life forms presently known to inhabit caves.
Fig. 2.2 Leptodirus hohenwarti, a highly cave-evolved beetle discovered in 1832 by the Count von Hohenwart in the Slovenian cave of Postojna Jama.
Kingdom MONERA
Phylum Bacteria
Well represented in caves. Includes saprophytes, pathogens and chemoautotrophs (which live by oxidizing or reducing iron and sulphur compounds). Bacteria are at the base of many cave food-chains.
Phylum Cyanobacteria
Some species are capable of synthesizing their pigments in the absence of light. Various Chroococcaceae are implemented in the formation of complex cave mineral deposits such as moon milk and tufa (see glossary (#litres_trial_promo)).
Kingdom PROTISTA
Phyla Phytoflagellata, Zooflagellata, Sarcodina, Ciliophora, Sporozoa
Protista are often abundant in interstitial waters and many species occur in caves. In Turkmenistan, brackish wells in the Kara-Kum desert contain abundant populations of at least 10 species of unusually tiny, thin-shelled Foraminifera. Cave clays often contain Mastigophora, Sarcodina, Amoebina and some Ciliata.
Kingdom PLANTAE
Phylum Chlorophyta
