Showing posts with label Fossil hunting. Show all posts
Showing posts with label Fossil hunting. Show all posts

Monday 27 August 2018

Hammer and chisel: the top ten reasons why fossil hunting is so important

At a time when the constantly evolving world of consumer digital technology seems to echo the mega-budget, cutting-edge experiments of the LHC and LIGO, is there still room for such an old-fashioned, low-tech science as paleontology?

The answer is of course yes, and while non-experts might see little difference between its practice today and that of its Eighteenth and Nineteenth Century pioneers, contemporary paleontology does on occasion utilise MRI scanners among other sophisticated equipment. I've previously discussed the delights of fossil hunting as an easy way to involve children in science, yet the apparent simplicity of its core techniques mask the key role that paleontology still plays in evolutionary biology.

Since the days of Watson and Crick molecular biology has progressed in leaps and bounds, yet the contemporary proliferation of cheap DNA-testing kits and television shows devoted to gene-derived genealogy obscure just how tentatively some of their results should be accepted. The levels of accuracy quoted in non-specialist media is often far greater than what can actually be attained. For example, the data on British populations has so far failed to separate those with Danish Viking ancestry from descendants of earlier Anglo-Saxon immigration, leading to population estimates at odds with the archaeological evidence.


Here then is a list of ten reasons why fossil hunting will always be a relevant branch of science, able to supply information that cannot be supplied by other scientific disciplines:
  1. Locations. Although genetic evidence can show the broad sweeps connecting extant (and occasionally, recently-extinct) species, the details of where animals, plants or fungi evolved, migrated to - and when - relies on fossil evidence.
  2. Absolute dating. While gene analysis can be used to obtain the dates of a last common ancestor shared by contemporary species, the results are provisional at best for when certain key groups or features evolved. Thanks to radiometric dating from some fossiliferous locales, paleontologists are able to fill in the gaps in fossil-filled strata that don't have radioactive mineralogy.
  3. Initial versus canonical. Today we think of land-living tetrapods (i.e. amphibians, reptiles, mammals and birds) as having a maximum of five digits per limb. Although these are reduced in many species – as per horse's hooves – five is considered canonical. However, fossil evidence shows that early terrestrial vertebrates had up to eight digits on some or all of their limbs. We know genetic mutation adds extra digits, but this doesn't help reconstruct the polydactyly of ancestral species; only fossils provide confirmation.
  4. Extinct life. Without finding their fossils, we wouldn't know of even such long-lasting and multifarious groups as the dinosaurs: how could we guess about the existence of a parasaurolophus from looking at its closest extant cousins, such as penguins, pelicans or parrots? There are also many broken branches in the tree of life, with such large-scale dead-ends as the pre-Cambrian Ediacaran biota. These lost lifeforms teach us something about the nature of evolution yet leave no genetic evidence.
  5. Individual history. Genomes show the cellular state of an organism, but thanks to fossilised tooth wear, body wounds and stomach contents (including gastroliths) we have important insights into day-to-day events in the life of ancient animals. This has led to fairly detailed biographies of some creatures, prominent examples being Sue the T-Rex and Al the Allosaurus, their remains being comprehensive enough to identify various pathologies.
  6. Paleoecology. Coprolites (fossilised faeces), along with the casts of burrows, help build a detailed enviromental picture that zoology and molecular biology cannot provide. Sometimes the best source of vegetation data comes from coprolites containing plant matter, due to the differing circumstances of decomposition and mineralisation.
  7. External appearance. Thanks to likes of scanning electron microscopes, fossils of naturally mummified organisms or mineralised skin can offer details that are unlikely to be discovered by any other method. A good example that has emerged in the past two decades is the colour of feathered dinosaurs obtained from the shape of their melanosomes.
  8. Climate analysis. Geological investigation can provide ancient climate data but fossil evidence, such as the giant insects of the Carboniferous period, confirm the hypothesis. After all, dragonflies with seventy centimetre wingspans couldn't survive with today's level of atmospheric oxygen.
  9. Stratigraphy. Paleontology can help geologists trying to sequence an isolated section of folded stratigraphy that doesn't have radioactive mineralogy. By assessing the relative order of known fossil species, the laying down of the strata can be placed in the correct sequence.
  10. Evidence of evolution. Unlike the theories and complex equipment used in molecular biology, anyone without expert knowledge can visit fossils in museums or in situ. They offer a prominent resource as defence against religious fundamentalism, as their ubiquity makes them difficult to explain by alternative theories. The fact that species are never found in strata outside their era supports the scientific view of life's development rather than those found in religious texts (the Old Testament, for example, erroneously states that birds were created prior to all other land animals).
To date, no DNA has been found over about 800,000 years old. This means that many of the details of the history of life rely primarily on fossil evidence. It's therefore good to note that even in an age of high-tech science, the painstaking techniques of paleontology can shed light on biology in a way unobtainable by more recent examples of the scientific toolkit. Of course, the study is far from fool-proof: it is thought that only about ten percent of all species have ever come to light in fossil form, with the found examples heavily skewed in favour of shallow marine environments.

Nevertheless, paleontology is a discipline that constantly proves its immense value in expanding our knowledge of the past in a way no religious text could ever do. It may be easy to understand what fossils are, but they are assuredly worth their weight in gold: precious windows onto an unrecoverable past.

Tuesday 13 May 2014

Digging apart: why is archaeology a humanity and palaeontology a science?

Although my Twitter account only follows scientists and scientific organisations, every day sees the arrival of a fair few archaeology tweets, even by science-orientated sites such as Science News. As someone who has been an amateur practitioner of both archaeology and palaeontology I thought I'd like to get to grips with why they are categorised so differently. After all, the names themselves don't really help: the word 'archaeology' means "the study of everything ancient." whilst the common definition of 'palaeontology' is pretty much "the study of ancient life". I've even known people with close friends or relatives in one or the other discipline to confuse them: whilst viewing my fossil cabinet, a visitor once told me that her cousin was an archaeologist studying Maori village sites!

Even historically, both fields share many common factors. Not only were they founded by enthusiasts and amateurs, but to this day non-professionals continue to make fundamental contributions. In converse, amateurs can cause serious deficiencies in the data record by lack of rigour or deliberately putting financial gain ahead of the preservation of new information. This can be caused by a variety of methods, from crude or overly hasty preparation of fossils, to metal detectorists and site robbers who sell their finds to private collectors without recording the context, or even the material itself.

It is not immediately obvious where the dividing line between the two disciplines lies when it comes to prehistoric human remains. In the 1990s, archaeologist Mark Roberts led a team that excavated the half a million year old Boxgrove site in southern England. Finds included fragmentary remains of Homo heidelbergensis, thus crossing over to what might traditionally be deemed the territory of palaeontologists. In 2001 the multi-phase Ancient Human Occupation of Britain project started, with deliberate collaboration between both sectors, proof that their skills could overlap and reinforce each other.

By and large, neither palaeontology nor archaeology utilises repeatable laboratory experiments and therefore neither can be classified as a ‘hard’ science. Even palaeontology relies to a large extent on historical contingency, both for remains to be fossilised in the first place and then for them to be discovered and recorded using the relevant methodology. As British palaeontologist Richard Fortey has said "Physics has laboratories; systematic biology has collections." Talking of which, re-examination of old evidence in both disciplines can lead to new discoveries: how often do we see headlines pointing to a fundamental discovery...made in a museum archive?

Although archaeologist were not previously known for conducting experiments,  the New Archaeology/Processual archaeology that arose in the 1960s included an emphasis on testing hypotheses, one result of which is that archaeology now uses experiments to interpret site data. This includes attempts to recreate artefacts, structures, boats, or even food recipes, based on finds from one or more sites. It may not be laboratory conditions, but it is still a method of analysis that can reinforce or disprove an idea in a close equivalent of the scientific hypothesis.

Attempts to improve the quality of data gleaned from the archaeological record have led to the utilisation of an enormous variety of scientific techniques collectively labelled archaeometry. These include microwear analysis, artefact conservation, numerous physical and chemical dating methods such as the well-known radio carbon dating and dendrochronology; geophysical remote sensing techniques involving radar, magnetometry and resistivity; and DNA analysis, pathology and osteo-archaeology.

Teeth of a sand tiger shark
(possibly Odontaspis winkleri)
I found in a wood in Surrey, UK

But there are some major differences between archaeology and palaeontology as well. Although both appear to involve excavation, this is only somewhat true. Not only does archaeology include standing structures such as buildings or ancient monuments, but a project can be restricted to non-invasive techniques such as the geophysical methods mentioned above; excavating a site is the last resort to glean information unobtainable by any other way, especially important if the site is due to be destroyed by development. In contrast, fossils are no use to science by remaining buried. Having said that, I often fossils by sifting through pebbles rather than concerted digging. I have occasionally split rocks or dug through soft sand, but a lot of the time fossils can be found scattered on the surface or prised out of exposed chalk via finger nails. The best way to spot even large finds is to have them already partially exposed through weathering, whilst some archaeology cannot be directly seen from the site but only identified via aerial photography or geophysics.

Archaeological sites can prove extremely complex due to what is known as context: for example, digging a hole is a context, back filling it is another, and any finds contained therein are yet more. Repeated occupation of a site is likely to cause great difficulty in unravelling the sequence, especially if building material has been robbed out. This is substantially different to palaeontology, where even folded stratigraphy caused by geophysical phenomena can be relatively easily understood.

Perhaps the most fundamental difference between the disciplines is that of data analysis. As anyone who has spent time on a site excavation knows, there are often as many theories as there are archaeologists. There are obviously far less fixed data points than that provided by Linnaean taxonomy and so there is a reliance on subjectivity, the keyword being 'interpretation'. Even the prior experience of the excavator with sites of a similar period/location/culture can prove crucial in gaining a correct (as far as we can ever be correct) assessment. In lieu of similarity to previously excavated sites, an archaeologist may turn to anthropology, extrapolating elements of a contemporary culture to a vanished one, such as British prehistorian Mike Parker-Pearson's comparison between the symbolic use of materials in contemporary Madagascar and Bronze Age Britain. In stark contrast, once a fossil has been identified it is unlikely for its taxonomy to be substantially revised - not that this doesn’t still occur from time to time.

As can be seen, not all science proceeds from the hypothesis-mathematical framework-laboratory experiment axis. After all, most of the accounts of string theory that I have read discuss how unlikely it can ever be subject to experiment. The British Quality Assurance Agency Benchmark Statement for Archaeology perhaps comes closest to the true status of the discipline when it lists 'scientific' as one of the four key contexts for higher level archaeological training. In addition, every edition since 2000 has stated "Where possible, thinking scientifically should be part of the armoury of every archaeologist."

So part historical science, part humanity, archaeology is an interesting combination of methodologies and practice, with more resemblances than differences to palaeontology. As the Ancient Human Occupation of Britain project shows, sometimes the practitioners can even work in (hopefully) perfect harmony. Another nail in the coffin for C.P. Snow's 'Two Cultures', perhaps?

Tuesday 24 December 2013

The great outdoors: getting children back to nature

With Christmas just around the corner it seems like a good time to look at the benefits of persuading children to swap their hi-tech electronic gadgets for the wonders of the great outdoors. The recently-slated Toys 'R' Us television advert that promotes their plastic junk at the expensive of a 'dull and boring' nature field trip only highlights a trend that as the rural population decreases, natural phenomena such as animals, weather and good, clean soil are deemed solely of interest to farmers. Some years ago, a London acquaintance who teaches English at a senior school reported that during a woodland walk - to explore nature poetry rather than nature itself - several of her female teenage students cried due to getting mud on their shoes. Just how distanced are children becoming from the world beyond their front door!
A sense of scale: humans against California redwoods

The last few decades have seen a move away from the outdoor adventures that typified my childhood: catching butterflies; building woodland dens; even exploring a derelict house. Instead, sitting in front of computers, TVs and games consoles has become prevalent, sometimes all at once. Not that this has gone unnoticed, as discussed in Richard Louv's best-selling Last Child in the Woods: Saving Our Children From Nature-Deficit Disorder. Although the phenomenon is common across the developed world, some countries fare better than others. For example, recent reports suggest New Zealand children (feeling a bit smug at this point) spend rather more time outdoors than their Australian, American or British counterparts. However, I'm sure there's room for improvement just about everywhere. There are many reasons behind the stay-at-home trend in addition to the obvious delights of being cosily tucked up with digital devices, but I believe it is more important to explore the effects this is having on our children:
  1. The most obvious problem caused by a shortage of physical activity outdoors - which after all is free, compared to the indoor play centres often used for children's parties - is the lack of opportunity to develop coordination and motor skills beyond the mouse or joystick. Since we've experienced a generation-on-generation increase in the number of calories, sugar and fat in our diet, then clearly there should also be an increased amount of time spent burning this off. Obviously this hasn't happened, and various groups such as the International Association for the Study of Obesity have tracked the post-war growth in overweight children. If you haven't seen any of the resulting graphs, they make for troubled reading...
  2. But it isn't just physical health that is affected. As a species, we are still coming to terms with urban living and the psychological problems of existence in near-identical cuboids in residential estates frequently bereft of greenery. The World Health Organization's definition of health includes mental well-being, which can incorporate the notion that regular playing outdoors confers benefits on children. I don't consider this as just referring to strenuous exercise: exploring the randomness of nature - from building sand castles to snowball fights - as well as the simple joys of experiencing weather at first hand, are also important. As if to confirm the problems that a lack of balance in indoor/outdoor activities can lead to, a work colleague recently informed me that his twenty-year-old son, a business degree student, was reduced to tears when he was unable to log on to his online gaming account for a few days. Oh, for an adequate sense of perspective!
  3. Does the changing emphasis from natural to man-made environments mean are we losing a vital part of our humanity? Or are we seeing a new form of evolution for our species? The differences between nature and artifice are profound, from the seemingly (although only from our viewpoint) haphazardness of the former to the non-messy convenience sought as a given via the latter. Even a basic understanding of processes from food at its source might be useful as an educative tool to engender empathy for a planet we are so rapidly despoiling. It's very easy for children to overlook the natural wonders that still exist in even the most densely populated of nations when they primarily associate the rural environment with the exotic non-developed locales usually favoured by natural history documentary programme makers.

    Viewing nature at second hand is no substitute for - literally - getting your fingers dirty, whether it is planting flowers or foodstuffs, or simply scrabbling over muddy terrain. A 2010 survey conducted in the UK indicated that between one quarter and one half of British children lack basic knowledge concerning familiar native and introduced species such as horse chestnut trees and grey squirrels. Not that I'm convinced an appreciation of the facts might lead to more environmental awareness; after all, how many times has the 'closer to nature' sustainability of pre-industrial societies been shown to be a myth? But considering for example the enormous amount of bought food that is thrown away uneaten (perhaps reaching over 40% in the USA) surely any understanding of the complex cycles within the far from limitless ecosystem may engender some changes in attitude towards reduce, reuse and recycle? As evolutionary biologist Stephen Jay Gould once said, we will not fight to save what we do not love.
  4. Further to the last point, knowledge as a safety net might come in handy, should the need arise. There's an old adage that even the most 'civilised' of societies is only nine missed meals away from anarchy, as the citizens of New Orleans learnt all too well in the wake of Hurricane Katrina in 2005. Considering just how much food manufacturers rely on oil for everything from transport to packaging (did you know North Sea prawns are flown on a 12,000 mile round trip to be cleaned and de-shelled?) it doesn't just have to be a natural disaster to generate such chaos. In October 2011 a leak in the Maui gas pipeline here in New Zealand led for a few days to empty bread shelves nationwide, highlighting the fragility of our infrastructure.

    A 2008 UK report concluded that British food retailers would exhaust their stocks in just three days in the event of a Hurricane Katrina-scale emergency, thus suggesting that those who follow chef and forager Hugh Fearnley-Whittingstall or adventurer/survivalist Bear Grylls will be the victors. I'm not suggesting children should be taught to distinguish edible from poisonous fungi but considering the potential dangers of even cultivated food crops (did you know that potatoes turning green may be a sign of the poison solanine?) any knowledge of foraging and food preparation may prove useful as well as fun.
  5. Encouraging children to explore outside is as good a method as any to beget a new generation of biologists, ecologists and their ilk. Ironically, Toys 'R' Us list over 370 items in the science and discovery section of their online catalogue. Indeed, their advert includes several seconds' footage of a boy looking through the eyepiece of small reflecting telescope labelled 'science', although judging by the angle the telescope is pointing into the ground! As I've explored previously, doing practical science seems to be a far better way to introduce young children to the discipline than mere passive viewing or reading. It can also demonstrate that - with several exceptions such as high-energy physics - many of the basic structures of scientific procedure and knowledge are well within the grasp of non-scientists (perceptions are hard to shift: I recently heard a law graduate declare she wasn't sure she would be able to understand this blog, as science is of course 'very difficult'! )

    Each one of the above alone would be reason enough to encourage children to spend more time outside, but taken together they suggest that there is likely to be severe repercussions across many aspects of society if the adults of tomorrow don't get enough fresh air today. It may sound like something out of a Boys' Own Journal from the era of the British Empire, but there's something to be said for the simpler pleasures in life. I know I'd rather go for a forest walk or rock pooling than play Grand Theft Auto 5 any day...

Wednesday 25 August 2010

Carving niches: are there still roles for amateur scientists?

Until the mid-nineteenth century the majority of scientists seem to have been unsalaried, so the barrier between paid practitioners and the rest of us is relatively recent. It has been said that with the contemporary emphasis on expensive equipment and increasing specialisation there is no room for dabblers in the field, but there is plenty of evidence to negate this. A good starting point is this year's BBC Amateur Scientist of the Year competition, which garnered over 1300 applications, some admittedly a bit on the fruitier side. So whilst Britain doesn't have anything to compete with the USA's Society for Amateur Scientists, there's clearly no lack of enthusiasm.

But of course anyone can dream up a bizarre idea without putting in the 99% perspiration afterwards. It is the latter that proves the mettle of the amateur scientist, prepared to doggedly test a hypothesis or utilise scientific techniques as and when time becomes available. It also seems to be true that there are very few amateur theoreticians: by and large, if you engage in science for fun, you're a practical person at heart. Many dedicate years to the cause, from those who tally local wildlife numbers (occasionally identifying new species, of which there are still plenty to be described scientifically) to the likes of Simon Cansick, whose website provides constantly updated weather forecasting data for his Yorkshire village. Mr Cansick may sound like the archetypal British eccentric, but his level of accuracy has apparently caused local farmers to snub the Met Office in favour of http://www.dugglenet.org/ instead.

The two main areas I've always considered easy for an amateur to explore are astronomy and palaeontology, mostly because the necessary equipment is comparatively cheap and readily available. Whilst large telescopes can cost a fortune, some enthusiasts build at least some of the mount themselves (as recommended by Patrick Moore, no less), if not necessarily going to the lengths of the brother and sister team William and Caroline Herschel, who several centuries ago cast telescope mirrors using the likes of horse dung for moulds. As a child I had a small refractor which was reasonably adequate for the limited seeing conditions in the light polluted sky of my small home town. I did however build my own observatory shed, complete with a sliding roof made from old wardrobe doors. Ah, the folly of youth!

Whilst it may seem daft for backyard astronomers to compete with 10 metre reflectors and orbiting telescopes, the world record for visual discoveries of supernovae is held by the Australian amateur Robert Evans, who has mostly utilised a variety of reflectors with primary mirrors under 50cm. Another example of amateurs at the forefront is the Transitsearch.org network, which helps part-time astronomers hunt for extra-solar planets using a combination of backyard telescopes and digital cameras, although to be sure the latter need to be in the several thousand pounds range.

As for palaeontology, I have already covered the delights of fossicking in an earlier post, although sad to say my daughters recently came away empty-handed from a trip to the Isle of Wight. Chips off the old block, they were lulled into thinking they might find dinosaur bone or even pterosaur remains by a University of Portsmouth palaeontologist they spoke to at the Royal Society's Summer Science Exhibition. Instead, the family returned with depressingly lightweight sample bags, the stars of which were a heavily worn tooth (most likely crocodile) and a possible gastrolith. As a brief aside, I must mention that the Royal Society event at London's South Bank Centre was in itself a superb example of encouraging amateur participation in science, with even my four year old donning goggles and latex gloves to conduct some nanoparticle experiments.

All in all, the idea that amateurs cannot conduct useful or even just enjoyable science couldn't be more wrong. And with the likes of cardboard telescope and microscope kits available for under twenty pounds, children can easily get on the bandwagon too, perhaps with a touch of parental persuasion. Now I have to go back the workbench and a 12 volt rotary grinding tool, as I've promised my children I'll find out whether the Isle of Wight tooth could just possibly be from a small iguanadon after all...

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Monday 15 February 2010

Palaeontological pastimes: fossicking for all the family

What do the Isle of Wight, the Dorset coast and a park in south-east London have in common? Answer: they are all popular stomping grounds for amateur fossil hunters, adults and children alike. Discovering fossils in Britain has a long pedigree, as shown by the antiquity of common names for popular species such as the Jurassic oyster Gryphaea: the Devil's toenail. Equally telling are the museum specimens of ammonites with snake heads carved on them, which were sold over the centuries as 'petrified serpents'. Whilst carving heads doesn't exactly do much for fossils in scientific sense, it is at least an improvement on the Chinese folk tradition of grinding up 'dragon bones' to make medicines!

Fossicking as a popular activity has grown enormously over the past few decades, both in the UK and elsewhere. During the first half of the nineteenth century talented British amateurs such as Mary Anning and Gideon Mantell pioneered techniques to respectively excavate and examine Mesozoic fossils, but since then the field appears to have almost wholly dominated by professionals. So why is it that over the past few decades fossil hunting has become a widespread activity for both children and their parents?

It's probably best to start with two books concerning those ubiquitous prehistoric beasts, the dinosaurs. Until the 1980s most books portrayed them as lumbering, frequently swamp-dwelling animals: slow, simple-minded, and boringly monochrome. Then in 1986 American palaeontologist Robert Bakker wrote The Dinosaur Heresies: New Theories Unlocking the Mystery of the Dinosaurs and Their Extinction, which promoted a more active, bird-like metabolism. Bakker's research (in many aspects now considered more mainstream than heretical) had the good fortune to be published at the same time that research into the 65 million year old iridium layer was gaining attention. In 1990, Michael Crichton's novel Jurassic Park became a bestseller shortly before the publication of a flurry of articles and papers discussing the Chicxulub crater in Mexico. For a while this enormous impact crater was combined with the worldwide iridium layer to offer a definitive solution to the dinosaurs' demise via asteroid impact, although the hypothesis has becoming increasingly untenable since. In the meantime, Steven Spielberg's 1993 film adaptation of Crichton's book became the highest-grossing film in history, confirming that dinosaurs were back in the public imagination on an unprecedented scale.

The continual development of computer-generated graphics has since led to numerous dramas and documentaries featuring these and other extinct ecosystems, often courtesy of the Discovery Channel and the BBC. Museums have also got in on the act, with dynamic, frequently animatronics exhibits ranging from the three-quarter sized Tyrannosaurus Rex at the Natural History Museum in London to the tiny hatchling at Oxford's equivalent. There have also been some international theatrical exhibitions featuring full-size reconstructions, including the £10 million Walking with Dinosaurs show at the O2 and Wembley Arena, as well as the new temporary exhibition at Parklife Oxford Street in London. Dinomania and then some!

Although these commercial enterprises have only been made feasible by the advances in animatronics and computer graphic technology, they appear closely tied to the flood of new finds and resulting theories. Many specialists now speak of a golden age of dinosaur discovery, supported by the recognition of a new species every few months and computers used to rapidly produce life-like reconstructions. The number of exciting finds, especially from China, supports the idea of a dinosaur renaissance, although hasty speculation on the dino-bandwagon often seems to drown out sober fact. One recent key discovery is the feathers and protofeathers found on various species: current research of their microscopic melanosomes has led to a claim of multi-coloured, possibly striped dinosaurs; a far cry from the bland grey and brown illustrations I remember from the 1970s. With embryo-containing eggs and nests also being found around the world, many aspects of dinosauria are becoming as well known as species alive today. Perhaps it is the increasing familiarity of some of these animals (as in their resemblance to giant proto-birds) which helps generate a feedback loop between scientific exploration and media exposition. The day of the dull dinosaur is over.

As for the British Isles, the popularity of dinosaurs has been used to generate enormous interest in amateur fossil hunting, with the Isle of Wight, home to the earliest ancestor of T-Rex, often considered the best location in Europe for finding dinosaurs. The island contains the Dinosaur Isle and the Dinosaur Farm Museum attractions, which combined with Norfolk's Dinosaur Adventure Park show there's no shortage of family-oriented 'edutainment'.

Of course there are many other genera to be found in the UK: the three-volume set of British fossils published by the Natural History Museum runs to over 500 pages. The main groups I have found whilst fossicking around the country are echoed by the limited choice of native specimens available in fossil shops, namely belemnites, ammonites, shark's teeth, and to a lesser extent, trilobites. Whilst these are mostly small specimens (anything large tends to be discovered by commercial operators after winter storms), there are still occasional finds showing the potential for amateurs. These include the 600,000 year old elephant found at West Runton beach in Norfolk; and Baryonyx, a 9.5 metre long fish-eating dinosaur that was discovered in a Surrey clay pit.

Many locations offered organised walks, including some just for one family at a time. Herein lies another reason for the popularity: many fossil-bearing strata are found in extremely accessible locations such as the coastline of popular holiday resorts, so it's far easier to combine a beach holiday with a fossil hunt than at equivalent, frequently remote sites in Australia or the USA. There is even a Family Fossil Hunt course on the Pembrokeshire Coast in Wales, aimed at introducing families to the joys of fossicking. For those who come away empty-handed (often the adults, since children usually have better eyesight and are closer to the ground), numerous gem shops and websites sell fossils in addition to paraphernalia such as geology hammers, goggles, and magnifiers. Again, many items are clearly aimed at children, including party bags (some with chocolate ammonites) and starter sets containing items such as dinosaur coprolites (fossilised dung).

By and large, fossil hunting is a fairly harmless activity. As long as you keep an eye on the tide and don't dig into cliff faces, there's not much that can go wrong with a leisure pursuit that can cost nothing more than some ziplock bags to contain your finds. If fossils are not extracted when exposed, the weather or wave action will soon erode or fragment them. As long as any unusual specimens are reported it's doubtful scientific information is being lost (unlike with metal detectorists, where archaeological context is everything). Without sounding too much like a public information film from the 1950s, fossicking is a healthy pursuit for all the family that can help promote interest in biodiversity and evolution (although if it is anything like what can be overheard at the Natural History Museum, the pre-teens often know more about it - Greco-Latin species names included - than their parents). And after all, in many locations as soon as you get bored you can always go back to building sandcastles!

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