Amphibians and Reptiles

By Trevor Beebee and Richard Griffiths

Building on the solid foundations established by the two earlier New Naturalist volumes on this subject, eminent herpetologists Trevor Beebee and Richard Griffiths have brought together a wealth of new and fascinating information on the British amphibians and reptiles.

An introductory chapter looks at the subject of biogeography and how factors such as geological history, latitude and climate affect ecology, life histories and behaviour. The authors then go on to discuss historical interest in amphibians and reptiles, from how they have featured in witchcraft and legends to modern perspectives. A third chapter covers basic biology of amphibians and reptiles, before each of the main groups – newts, frogs and toads, lizards, snakes and chelonians – are examined in further detail. A comprehensive account for each species covers behaviour, life history, reproduction and distribution, as well as ecology and conservation status, areas in which significant discoveries have been made in recent years. There is also a chapter with important new information on the burgeoning number of introduced species in Britain, such as bullfrogs, alpine newts and wall lizards.

During the last half century, amphibians and reptiles have been among the most serious casualties of the changing way of life in the British countryside. In recognition of the threats they continue to face, Beebee and Griffiths rightly dedicate a final, substantial chapter to the increasingly important issue of conservation and discuss the measures needed to be taken to ensure the future survival of the British herpetofauna.

With over 100 black and white line drawings and illustrations, and an 8-page colour section, this is an authoritative work on a subject of great natural history interest.

• Language: English
• Publisher: HarperCollins UK
• Release date: Aug 14, 2014
• ISBN: 9780007401352

Book preview

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Amphibians and Reptiles in Britain

The island perspective

Living on an archipelago of several hundred islands has undoubtedly been a mixed blessing to the various native inhabitants of the British Isles. From the perspective of recent human history it has served, until very recently, to minimise the movement of individuals into and out of Britain. In biological terms, gene flow between populations has been small; in more familiar language, successful invasions have been rare and in this sense the advantages of island life were evident as recently as the Second World War.

The development of biogeography as a scientific discipline in its own right (Vincent, 1990) has, since the 1960s, generated a much clearer idea of the biological differences between islands and continental mainlands. Island biogeography theory shows that the number of species that an island can support is, other factors being equal (which often they are not), directly related to its size. So we expect biodiversity in Britain to be less than that of neighbouring mainland areas at the same latitude, such as the Netherlands, and it surely is. Exactly the same is true if we compare islands within the British archipelago; the Isle of Wight is impoverished relative to mainland Britain, and so on. In the specific case of herpetofauna, the British Isles have 12 or 13 native terrestrial amphibians and reptiles (Table 1), but the Netherlands has 22 species and the Isle of Wight just nine. Europe as a whole, bearing in mind occasional uncertainties of both geographical boundaries and species definitions, has more than 60 amphibians and twice as many reptiles (Gasc, 1997). Even so, when considered over long periods of time, islands often turn out to be particularly interesting places because isolation with relatively few competitors is a good recipe for speciation and thus the generation of completely new life forms. But for the naturalist, with a mere three score years and ten available, islands in general are not the most rewarding of places for studying complex communities. Herpetologists in Britain have long recognised this fact and compensated by investigating the few species we do have in considerable detail.

The role of climate

Biodiversity in Britain does not just reflect its island status, but has also been heavily influenced by past and present climate, and of course by the variety of geology and topography available to generate a range of different habitats. The geographical location of the British Isles, set at the northwest corner of Europe but bathed by the warm waters of the Gulf Stream, results in an oceanic climate with much milder winters but cooler summers than are normal for the latitude. This undoubtedly increases biodiversity above what it would otherwise be, although the benefits may be smaller than initially expected. This is because maximum summer temperatures are often more important to ectotherms such as reptiles and amphibians than are minimum winter ones. Surviving under ice is usually less problematic than successful reproduction and many species of herpetofauna are limited at the northerly edges of their ranges by the summer temperatures needed for egg incubation or sufficiently rapid tadpole growth. Among the species found in Britain, sand lizards and smooth snakes experience low breeding success in cold or unusually wet summers while edible frog tadpoles only survive to metamorphosis in any numbers during warm ones. It has been noticed (Jackson, 1978) that the distribution of sand lizards in Britain can be related to May sunshine hours (Fig. 1). The argument goes that weather in May is critical to the time of egg-laying and thus to subsequent breeding success in this species. Delayed oviposition in a cool spring may well leave insufficient time for the eggs to hatch, but it is always difficult to prove cause and effect by such simple correlations. Even so, it is remarkable that Coli, a Hebridean island to which sand lizards were successfully introduced 30 years ago, lies within the May sunshine hours range of all the more southerly native populations. By contrast, atypically cold winters such as that of 1962–3 were not followed by amphibian or reptile declines and there is even anecdotal evidence that intense cold can sometimes be favourable. Several herpetologists have noted unusually large breeding congregations of common frogs, for example, when the ice has thawed after a severe freeze. Continuous cold weather prevents all amphibian or reptile activity whereas mild winters sometimes tempt the animals abroad or increase their metabolic rates, thus utilising energy reserves at a time of year when they are difficult to replenish. Survival is therefore probably better when winters are cold, providing the animals are secreted in frost-free retreats below ground or at the bottom of ponds. Nevertheless, amphibian and reptile diversity in Britain is certainly higher than it would be without the Gulf Stream. Newfoundland, a comparable island slightly further south than Britain but without the benefit of warm oceanic currents, boasts no native amphibians or reptiles at all despite its proximity to a continent which in total has four times more species than Europe.

Table 1 The native British amphibians and reptiles.

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*Controversial; pool frogs mayor may not be native.

Fig. 1 Sand lizard distribution in relation to May sunshine hours. 6.5 = 6.5 hours of sunshine isohel averaged 1901–1930; solid squares = areas with native populations; open squares = areas with introduced populations; open circles = areas with recently extinct populations. Reproduced after modification from Jackson (1978), with permission.

The importance of history in biogeography

Henry Ford’s infamous contention that ‘history is bunk’ is nowhere more easily refuted than in the science of biogeography. It would be quite impossible to understand the current distributions of plants and animals in Britain, or anywhere else, without a knowledge of past events. Twenty thousand years ago much of northern Europe including a large area of the British Isles was buried beneath an enormous ice sheet. The quantity of water contained in the polar ice caps was such that sea levels were some 100 metres lower than those of today and dry land connected the British Isles to each other and to France, Belgium and the Netherlands (Vincent, 1990). At that time conditions that have been compared to tundra prevailed in those parts of southern Britain not covered by ice, and it is highly unlikely that any species of amphibian or reptile survived anywhere in what later became the British Isles. Current distributions of a wide range of plants and animals that now live in Britain, including herpetofauna, imply that for tens of thousands of years during this ice age many hung on in refugia around the northern edge of the Mediterranean Sea. The Mediterranean forms a very deep trench that did not dry out during the period of low sea levels and thus remained as a barrier to further movement southwards. Quite probably this is why North America, lacking such an impediment to southerly escape and recolonisation routes, now has many more species of amphibians and reptiles than Europe. Iberia, Italy and the Balkans provided the last chance in terms of survival for European herpetofauna during the peak of the glaciation (Steward, 1969) and it is from these areas that they moved north again as the ice retreated.

Although the picture remains fragmentary, continuing studies of events since the last ice age are improving our understanding of what happened during this period of profound change. Evidently the warming began some 15,000–18,000 years before present (BP) and by around 12,000 BP temperatures were as high or higher than they are today. During this time there is evidence of rapid range expansions by many species northwards from the Mediterranean and at least some amphibians and reptiles certainly reached Britain. These included natterjack toads, which probably survived the ice age only in Iberia. Carbon dating of fossil natterjack remains from caves in south Devon demonstrate their presence there more than 11,000 BP (Gleed-Owen, 1997). However, a short period of intense cold, the ‘Younger Dryas’, intervened between about 11,000 and 10,500 BP. This returned tundra conditions to much of Britain, and it is improbable that any herpetofauna could have survived so far north. Even so, it is also unlikely that there was a retreat to anything like the restricted ranges of the glacial maximum, and increasing evidence suggests that many species of animals and plants rode out the Younger Dryas in refugia relatively far north in Europe. After 10,000 BP there followed a period of very rapid warming, reaching temperatures at least as high as modern ones within a few hundred years. Indeed, this trend continued for several millennia, and between about 8,000 and 5,000 BP there was a climatic optimum during which summer temperatures in southern England were 2–3°C warmer than they are now. Afforestation followed quickly in the wake of the retreating ice and the pollen record suggests that tree cover was more or less complete over most of Britain by 9,000 BP (Vincent, 1990). This means that species requiring open habitats, especially the natterjack toad, sand lizard and smooth snake, must have reached the limits of their present distributions by that time. Around 5,000 BP temperatures were in decline again, a slow trend which has continued with one or two minor hiccups in both directions up to the present day. These included a ‘mini-optimum’ about 700–800 BP when wine production became widespread in southern England and a ‘mini ice-age’ about 300 BP when the Thames regularly froze in winter. Human impact on the landscape became significant from about 5,000 BP onwards, reducing forest cover and creating open fields as well as the heathlands so favoured by many of our herpetofauna ever since. Now, of course, we face the spectre of global warming with a trend towards increasing temperatures evident in the records of the past 100 years and accelerating markedly within the last 30. In the absence of this anthropogenic effect we would expect, on the basis of patterns identified in previous interglacial periods, a continuous decline in temperature ultimately precipitating another full glaciation within the next few thousand years.

It follows that the amphibians and reptiles to be found in Britain today almost certainly all colonised the islands immediately after the end of the Younger Dryas. A complicating factor, however, was the accompanying rise in sea levels which got under way more than 15,000 BP. By 10,000 BP, the critical time, England was still joined to northeast France, Belgium and the Netherlands. This link was finally severed, probably between East Anglia and the Netherlands, some 8,000–8,500 BP. If there were Younger Dryas refugia in north-central Europe it is not too surprising that the more enterprising species of amphibians and reptiles made it into England within the 2,000 years or so available to them. No amphibian can survive prolonged immersion in seawater and although some terrestrial reptiles fare rather better (grass snakes have occasionally been caught well out at sea) it seems improbable that colonisation by herpetofauna continued after Britain separated from mainland Europe.

Outstanding problems

Unfortunately this simple picture is not completely adequate as an explanation of current herpetofauna distributions in Britain. Two particular difficulties remain. Firstly there is the question of species not present in Britain but which might reasonably be expected. A walk on the Calais or Boulogne sand dunes in spring quickly brings this issue home. Midwife toads (Alytes obstetricans), tree frogs (Hyla arborea), parsley frogs (Pelodytes punctatus) and alpine newts (Triturus alpestris) abound. Not far distant are salamanders (Salamandra salamandra) and wall lizards (Podarcis muralis). None of these species are generally considered native to Britain, although most have been successfully introduced in various places within the past 200 years. There are at least two credible explanations for their otherwise absence. Perhaps they are simply slow colonisers and moved north too late to arrive before Britain became separated by sea. Maybe, for whatever reason, they did not have any successful nearby refugia during the Younger Dryas and thus also had further to travel. Late arrival does seem a very plausible reason why species that live next door, that can survive in Britain, and that in some cases (such as alpine newts) prosper exceedingly well when introduced, nevertheless failed to make it naturally. A second possibility, however, is that they did get here long ago but subsequently died out. This would, after all, be in accord with island biogeography theory, and extinctions since the original colonisation might have occurred due to permanent or temporary climatic deterioration. There are precedents for such events. Fossil evidence from East Anglia proves that the European pond tortoise (Emys orbicularis) occurred in Britain after the last glaciation but seems to have disappeared at the onset of climatic cooling around 5,000 BP (Smith, 1951). Today its nearest station is in north-central France and British summers are now not usually warm enough for its eggs to hatch. Recent examinations of fenland fossils also suggest that two amphibians, the moor frog (Rana arvalis) and the agile frog (R. dalmatina), were also postglacial residents for a while. It is much less obvious why these species should have died out. Moor frogs still occur as close as Belgium and agile frogs persist on the island of Jersey and in northern France. For moor frogs Belgium is presently the most westerly outpost, so this species may have contracted eastwards for some reason, while agile frogs in general have a more southerly distribution, perhaps needing a more continental climate than Britain can offer today.

The second unresolved problem is more difficult but arguably more intriguing. Although the evidence is less clear and therefore more controversial, it seems likely that Ireland became separated from the rest of Britain within a few hundred years of the Younger Dryas ending. Certainly this separation must have been much earlier than that of England from mainland Europe. Ireland has an impoverished flora and fauna compared with the rest of Britain, as we might expect, but nevertheless some species apparently got there of their own accord during the postglacial warming. Among the herpetofauna, the smooth newt (Trìturus vulgaris) and viviparous lizard (Lacerta vivipara) are widely agreed to be native. Uncertainty surrounds the status of the other two species that have been present in Ireland at least for hundreds of years, notably the common frog (Rana temporaria) and the natterjack toad (Bufo calamita). Cases have been made that both of these were introduced by man and it has to be recognised that human interventions sometimes complicate the interpretation of biogeography. There is good evidence, for example, that green toads (Bufo viridis) and viperine snakes (Natrix maura) were introduced to the Balearic Islands by human agency. However, recent studies suggest that the natterjack and common frog are probably also long-standing natives of Ireland. How, then, did animals of rather low mobility cover the necessary distances within the very short time available? And why these particular species?

The short answer is that we do not really know, but there are some fascinating clues. The natterjack toad is one of a group of animals and plants collectively known as the Lusitanian element which occurs in Ireland and Iberia, but rarely or not at all in Britain (Vincent, 1990). Other members of this group include the strawberry tree (Arbutus unedo) and the Kerry slug (Geomalacus maculosus). Usually, but not always, the Lusitanian species (of which there are more than a dozen) are confined to the west or southwest of Ireland. Within England and Wales there is also increasing evidence, largely based on genetic studies, of ‘east-west divides’ among species found on both sides of the country. Organisms as diverse as field mice, brown trout and oak trees from eastern and western Britain retain echoes in their DNA of divergent recent ancestries. Intriguingly, the same is true of natterjack toads. Those found on the Irish sea coast of northwest England are genetically very different from those in East Anglia and southeast England, but are strongly allied to those in southwest Ireland. Another piece of evidence which must somehow be slotted into the jigsaw is the existence of fossil natterjack remains, dating from the period immediately after the Younger Dryas, in Devon – a county with no records of the species in historical times.

How can all these facts be explained? One possibility increasingly supported by genetic evidence is that modern distribution patterns have been heavily influenced by events during the Younger Dryas, when some species probably survived in more than one local northerly refugium following their previous expansion from the Mediterranean regions. Perhaps for natterjacks there were two such refugia, one somewhere around the English Channel and another much further east towards the Rhineland (Fig. 2). Animals from both areas successfully colonised Britain, but in such a way that the two invasions never met. On this scenario the western colonists gave rise to the Irish Sea and Kerry natterjack populations while the easterly invaders occupied East Anglia and the Thames basin. Of course this remains speculative. It is odd, for example, that no natterjacks have survived into recent times on any of the sand dune systems that seem to offer ideal habitat in southwest England and south Wales. It may be that these particular coasts, which are gradually sinking, have not supported dune systems continuously since the postglacial warming. While trying to reconstruct past events it is important to bear in mind not only how much we still do not know, but also the uncertainties about some of the data on which are built our hopeful hypotheses. Especially relevant in this context is a continuing debate about prospective land bridges between Wales or southwest England and Ireland which, if true, could go some way towards explaining the rapid colonisation by Lusitanian species. Fortunately there is every hope that some of these issues will eventually be resolved by further research and that one day a fully convincing reconstruction of postglacial British biogeography will emerge.

Modern times

Within the past few centuries the distributions of amphibians and reptiles, as of most other wildlife in Britain, must have been more and more influenced by human activities (Rackham, 1986). Not surprisingly, the results have been mixed. Reduction in forest cover is, in general, likely to have favoured most species of herpetofauna. This would be particularly true of reptiles. Large-scale drainage of the fens and other wetlands, intensifying after the seventeenth century, must have been bad news for many amphibians and might have brought the pool frog to the brink of extinction. On the other hand, the enclosure acts led to a multiplicity of small fields with corner ponds, a network of ideal freshwater habitats for amphibians which probably peaked in the late nineteenth century. Since that time most of the changes have been to the disadvantage of amphibians and reptiles. These issues are the subject matter of Chapter 10, concerned as it is with the conservation of herpetofauna in Britain.

Fig. 2 Possible postglacial colonisation routes of natterjack toads into Britain.

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Historical Interest

Within the science of zoology it is slightly unusual to have two distinct classes of vertebrate animals – the Amphibia and the Reptilia – lumped within a single discipline, in this case known as ‘herpetology’. The term herpetology is not in itself particularly informative as it stems from the Greek term herpeton, simply meaning a crawling thing. That these two groups of animals are often studied together owes as much to history and past traditions as it does to scientific endeavour. In fact until the beginning of the 1800s there was considerable confusion over the classification of amphibians and reptiles. Despite their affinities with frogs and toads, newts and salamanders were considered to be ‘water-lizards’, lizards were lumped with crocodiles and the slow-worm was thought to be a serpent. Indeed, the term ‘reptile’ was still being used to describe certain amphibians, as well as vice versa, in literature dating up to the turn of the twentieth century.

Although many of the fundamental problems in amphibian and reptile classification have now been resolved, there remains much to be done at lower taxonomic levels. The number of species known to science has increased over the past few decades and undoubtedly will continue to do so in the near future. This is because the development of new technologies such as molecular genetics has enabled biologists to examine the evolutionary relationships between species more precisely than ever before, and what was once considered to be a single species often turns out to be two or more. In addition there must still be many new amphibians and reptiles waiting to be discovered in remote corners of the world. Glaw & Vences (1998) recently calculated that the number of described amphibian species already exceeds that of mammals and by the year 2000 will have reached at least 5,000.

The names of amphibians and reptiles

Present-day names of the British amphibians and reptiles have fascinating and ancient histories. Some can be traced back to Anglo-Saxon origins including ‘frogga’, forsc’ and ‘froskr’ for frogs, and ‘tadige’ and ‘tadde’ for toad. As the term ‘polle’ means ‘head’ it is not difficult to see how ‘tadpole’ evolved to mean ‘head of the toad’, presumably referring to the fact that the body of a tadpole appears to be nearly all head! An alternative name for the tadpole stage, now rarely used, is ‘pollywog’. The origins of this are unclear, but it probably means ‘small animal with a large head’. At least three British species have names apparently derived from the Anglo-Saxon word ‘naedre’ which means ‘nether’ or ‘lower’. This seems to be a general term applied to a variety of organisms that crawl close to the ground. Thus ‘nedre’, ‘eddre’ and ‘nadder’ are all corruptions that manifest themselves within ‘adder’ and ‘natterjack’. Natterjack combines a derivation of ‘naedre’ with another old word, ‘jager’, meaning ‘one who runs’. Perhaps it is no coincidence than an alternative common name for the natterjack is the running toad, which is a very apt description of its mode of locomotion. ‘Naedre’ may also have been transformed to ‘Nadere’ and later ‘Natrix’, which is the generic name for the grass snake. However, ‘Natando’, which means ‘swimming in water’, is an alternative precursor for this genus of water-loving serpents.

The word ‘newt’ also has Anglo-Saxon origins and is derived from ‘efete’. This converts to ‘an evet’ or ‘a nevet’ and eventually to ‘a newt’. Today the immature stages of the North American red-spotted newt are known as ‘red efts’ and ‘eft’ is a convenient and increasingly used descriptor for the recently metamorphosed stage of the British species.

Early herpetology

It is difficult to pin down exactly when the first literature dealing specifically with amphibians and reptiles appeared. Pliny’s Naturalis Historiae of 1469 and Aristotle’s Historia de Animalium of 1495–98 are often cited as being among the earliest of writings on natural history. Edward Topsell’s renowned The History of Four Footed Beasts and Serpents of 1607 and its subsequent modifications is regarded as the first book to be published on natural history in the English language. It includes comprehensive accounts of a wide range of amphibians and reptiles including some species – such as the dragon – whose affinities are rather unclear! Even though these evocative early accounts are often enshrined by myth and misconception, there are clues within the writings that the earliest naturalists were highly perceptive and were seeking to explain their observations as best they could. For example, on the subject of frog hibernation Topsell had the following to say: ‘And of the frogs it is that Pliny was to be understood when he sayeth that frogs in the winter time are resolved into slime, and in the summer they recover their life and substance again.’ The sudden appearances and disappearances of amphibians and reptiles according to the seasons has puzzled naturalists for centuries and many other fanciful explanations for such phenomena have been proposed over the years.

It is unfortunate that even today amphibians and reptiles are regarded with revulsion and fear by many people. Their cause was done no good by the father of the present-day biological classification system, the Swedish botanist Carolus Linnaeus. His Systema Naturae was published in several editions between 1739 and 1766 and laid down a simple system for describing each species of animal and plant using a two-part Latin name comprising the genus and species. It is well known that Linnaeus had an abhorrence of amphibians and reptiles as is evident from the oft-quoted passage in which he describes them as ‘These foul and loathsome animals…’. Many of the Latin names that Linnaeus proposed are still in use today, although his lumping of amphibians, reptiles and cartilaginous fishes within a the single class ‘Amphibia’ has subsequently been modified!

By the time Thomas Bell’s A History of British Reptiles was published in 1839, a number of scientific societies had been formed which provided a more formal platform for the communication of new discoveries in natural history. Foremost among these were the Linnean Society, the Royal Society and the fledgling Zoological Society of London. Thomas Bell was a Secretary of the Royal Society and presided over the now famous meeting of the Linnean Society in 1858 when the Darwin-Wallace papers on the origin of species by natural selection were read for the first time. Although these ideas were to change the course of biological thinking forever, Bell remained sceptical about the theory of evolution for the rest of life and in his Presidential address to the Linnean Society commented that the year had passed unmarked by any striking discoveries! His book on British reptiles, which also included amphibians, is distinguished by eloquent descriptions of their natural history and distribution and some excellent woodcut illustrations (Fig. 3).

Fig. 3 Woodcut pictures from Bell’s A History of British Reptiles (1839). Natterjack toad, smooth newts, adder and grass snake.

Thomas Bell retired to the house at Selborne where Gilbert White had lived during the previous century and written the letters which comprise The Natural History of Selborne. This village is but a few miles from one of the last remaining natterjack toad populations in southern England. Natterjacks were obviously once much more widespread in this area and Bell comments: ‘The greatest number which I have ever known, however, is in my own garden at Selborne, where the species is far more frequent than the Common toad.’ What is intriguing about this observation is that despite their apparent abundance in the 1830s Gilbert White never mentions natterjacks being present in the same garden in any of his writings. It seems inconceivable that a naturalist with the keen observational eye of White would miss such a species in his own backyard and one can only assume that they were absent in his time. Later still Bell states that the natterjacks subsequently abandoned the garden. In the first New Naturalist on British amphibians and reptiles, Malcolm Smith suggested that such observations are in keeping with the tendency of entire natterjack populations to vacate one area and migrate somewhere else en masse. Only in recent years have we started to understand that many amphibian populations including those of the natterjack toad fluctuate considerably from year-to-year quite naturally. Rather than witnessing mass migrations of whole colonies it seems more likely that Gilbert White and Thomas Bell were observing natural variations in amphibian population size some 150 years before scientists began to realise that such phenomena are commonplace.

Folklore, myths and magic

Amphibians and reptiles the world over have long featured in local folklore and mythology. The species native to Britain are no exception in this regard and some myths such as the wart-inducing ability of the toad and the stinging properties of a snake’s tongue have perpetuated through to the present century. Although the origin of most such tales is unknown, many stem from an inability to explain what has actually been observed in nature and may therefore be rooted in fact. As stories are passed from generation to generation they become distorted and embellished along the way and the original observation that precipitated the tale frequently becomes obscured.

Amphibians and reptiles, or at least extracts from them, have regularly featured as ingredients in tonics and potions produced by ancient apothecaries. As is clear from Shakespeare’s Macbeth, amphibians were considered an essential component of a witch’s brew, but it is particularly the toads and newts who have suffered most in this regard. When mixed with certain wild herbs, extracts from toads were supposed to provide a cure for gout. According to Edward Topsell it was recommended that a live toad should be bored in the foot and hung by a thread in oil ‘until yellow’. It was also widely believed that a toad possessed a precious stone in its head. If the stone should be extracted from the toad alive using a piece of scarlet cloth, and then set in a ring, it was said to confer immunity to ‘gripings and pains of the belly and guts’. Perhaps the origins of the precious stone are connected with the rather beautiful copper-coloured eye of the common toad.

Paradoxically, many species were considered able to cure various afflictions of mankind while at the same time feared for their supposed toxic or supernatural properties. In Ireland, for example, smooth newts were once burnt as ‘devil’s beasts’. Furthermore, they were believed to enter the mouths of those who fell asleep in fields or drank from ponds and then live parasitically within the gut. On the other hand, the tongue of the same animal was said to cure scalds and burns, and a newt placed in an iron pot under the bed of a sick person was believed to alleviate disease. Intriguingly, Topsell seemed to have some doubt about these tales, and in the use of newts in particular, as is clear from the following passage taken from The History of Four Footed Beasts and Serpents: ‘There be some apothecaries which do use this newt instead of skinks or crocodiles of the earth, but they are deceived in the virtues of and operation, and do also deceive others, for their is not in it any such wholesome properties, and therefore not to be applied without singular danger. ’

Frogs have been attributed with some curious affects on women. If the tongue of a frog was cut out and laid upon the heart of a woman, then she was said to answer truthfully any questions asked of her by a man. Frogs were also deemed to possess contraceptive properties as it was also believed that a woman placing a frog in her mouth and spitting three times would not conceive that year.

Some species were thought to cure ailments caused by others. For example, according to Topsell ‘The water wherein an adder is preserved is a remedy against the poison of a toad.’ Equally, ‘adder’s fat’ was widely thought to have curative properties and Harry ‘Brusher’ Mills, the famous nineteenth century snake-catcher of the New Forest, was said always to carry a quarter pint of this concoction which he would apply to the site of a snakebite. In fact the healing properties of snakes can be traced as far back as Asklepios, the Greek god of medicine who was always associated with snakes and was believed to be able to transform into one. Since then snakes have often been used as an emblem of the medical profession. Tonics and potions obtained from snakes have been employed for a wide variety of medical and cosmetic purposes including cures for baldness, poor skin condition, rheumatism and the plague. Sloughed snake skins were also believed to have medicinal properties and it is said that an old man once sold them on the steps of King’s College, Cambridge, as a cure for headaches. Although such practices may seem strange in the light of modern medical advances, the blood and flesh of snakes still form an important component of traditional medicines and tonics in many Far Eastern countries.

It is also clear from old writings that amphibians and reptiles were often associated with natural phenomena which at first sight seem to have no modern counterpart. Stories of ‘raining frogs’ and ‘plagues of snakes’ can be traced back to biblical times and have regularly appeared in literature ever since. Quite likely such tales stem from observations of natural seasonal behaviours that have, perhaps, been misinterpreted. Common frogs and toads are ‘explosive breeders’ that turn up at breeding sites in large numbers for just a few days each year. Breeding activity is regulated by environmental conditions, and mild damp nights early in the spring are conducive to behaviour that can sometimes be spectacular – one day a pond is empty, the next it is alive with breeding amphibians. We now know that when on land, frogs and toads spend a lot of time in hiding places where they can be difficult to find, but to the early naturalists the sudden appearance of hundreds of frogs or toads under warm wet conditions perhaps led to just one conclusion – that they fell from the sky with the rain. Again, when the tadpoles of common toads metamorphose they often do so synchronously and the edge of a pond may teem with thousands of toadlets each no bigger than a spider. No doubt early naturalists did not fully appreciate the intricacies of amphibian metamorphosis or even that these tiny animals were once tadpoles at all. The most logical conclusion may therefore have been that it was raining toadlets.

The sudden emergence of snakes from hibernation and the onset of their breeding activity, as well as the emergence of young from communal nesting sites, perhaps goes some way towards explaining similar reports of plagues of snakes. One very well-documented account of this dates from the turn of the century and was described by Gerald Leigh ton in his book The Life-History of British Serpents. It concerned a story in the Morning Leader dated September 1900:

‘The residents of a house near Cefncaeau, near Llanelly, are suffering from a plague of snakes. The reptiles are of all sizes and colours, and they crawl over the floors, infest the cupboards, and curl themselves up on the furniture, and even luxuriate in the bedrooms. No fewer than twenty-two snakes were slaughtered in one day.’

Correspondence between Leighton, the local sanitary inspector and residents revealed an intriguing state of affairs. Adult grass snakes were abundant in the area and were frequently killed by local people. The animals observed crawling around the house all turned out to be hatchling grass snakes that had issued from a hole in the back wall. When the wall was subsequently opened up for repair work some 40 clutches of about 30 eggs each were discovered, all close to hatching. These were hastily despatched. It seems, then, that the 22 individuals initially found in the house were just the first from a much larger communal nest containing around 1,200 unhatched snakes. As Leighton muses, ‘It is almost a pity that the repairs were not deferred for another week or two, when the condition of things would have been a sight worth seeing.’

Another issue which Gerald Leighton and others, including Malcolm Smith, discuss at some length is whether or not female adders can swallow and later regurgitate their newborn young when they are threatened. There are numerous accounts of adders being killed and live young snakes escaping from the ruptured body cavity. As adders give birth to fully developed young rather than laying eggs, what was probably being witnessed was the escape of animals that were about to be born naturally rather than young snakes which had just been consumed. Rapid swallowing of several hatchlings would, we now know, be a physiological impossibility. First-hand testimonies of the act of swallowing are in any case hard to find and as with much folklore it is probably a case of stories being passed on with some imaginative