Spirals in Time: The Secret Life and Curious Afterlife of Seashells

by Helen Scales

  Living up in open water, where there are no caves to lay their eggs, female argonauts make their own portable, protective nooks to nurture their young. But their shells aren’t just brood chambers, they do other things besides. Watching argonauts for brief periods in aquariums, some scientists have argued that air trapped inside their shells is nothing but a nuisance, making it difficult to steer and stranding the animals at the water surface. Others have entertained the possibility that argonauts wilfully manipulate air bubbles inside their shells, and use them like underwater blimps.

  It wasn’t until 2010 that this matter was put to rest, when Julian Finn from Museum Victoria in Melbourne, Australia paid a visit to the Sea of Japan. Three female argonauts were caught in fishing nets offshore and brought into Okidomari Harbour, where Julian climbed into his scuba gear and carefully took the argonauts with him down beneath the waves. He emptied all the air out of their shells and released them, one at a time, and watched while all of the argonauts performed the exact same routine.

  First the argonauts zipped straight upwards, squirting themselves along using jet propulsion. Arriving at the surface, they squeezed out an especially vigorous jet of water that let them bob up and draw as much air into their shells as possible. Next, the argonauts repositioned their funnels and jetted back down, pushing themselves deeper and deeper. Being essentially open to the water and not fully sealed off, the air bubbles inside their shells were squashed, and shrank as the argonauts swam down and the pressure around them increased. Eventually the argonauts reached a depth where the air volume inside their shells cancelled its weight and the animals became neutrally buoyant, and therefore effectively weightless: they didn’t sink or float but hovered in the water column. On reaching that magic depth, between seven and eight metres (about 25 feet) down, the argonauts scooted off horizontally at high speed, swiftly outswimming Julian and his diving assistants.

  Watching them disappear from sight, Julian was certain that the argonauts were deliberately using air as a tool to help them swim efficiently at a shallow depth beneath the sea surface, where they are less likely to get knocked around by waves or picked off by a hungry seabird from above. It would explain why the exhausted argonaut brought to the Cabrillo Marine Aquarium needed a helping hand to fill up her shell at the surface and gain some much-needed buoyancy.

  Modern genetic studies confirm that the paper and chambered nautiluses are only distant cousins. Argonauts are without doubt octopuses, members of the coleoid lineage alongside cuttlefish and squid. And the nautiluses are the last few survivors of an ancient cephalopod pedigree, the nautilids, that have been doing their own thing for more than 400 million years.

  After all that time, these two groups of animals are living proof that having a gas-filled shell is an efficient way of moving through the oceans. They may not be as agile and swift as some of their cephalopod relations, but they are certainly not as primitive or outdated as the label ‘living fossil’ implies. And we now know for sure that when nautiluses die and leave their shells behind, argonauts don’t pick them up and use them.

  But humans do.

  CHAPTER EIGHT

  Hunting for Treasures

  In the silver gallery at the Victoria and Albert Museum in London – among the hundreds of gleaming goblets, crowns, platters and spoons – is a nautilus cup. It is made from the shell of a chambered nautilus that lived around 400 years ago, and since its death has been transformed.

  Most of the shell’s ochre stripes have been scraped carefully away to reveal the gleaming mother-of-pearl underneath; glimpses of tiger markings have been left here and there, woven into a swirling design carved across its surface. On the shiny parts a gathering of animals are engraved in fine detail: spiders, wasps, moths and ladybirds. The shell is cradled in a silver gilt mount decorated in enamelled flowers and tendrils, with more insects clambering through them.

  The nautilus cup was made in the Netherlands in around 1620. It was probably never actually used as a vessel but would have been put on display in a cabinet of curiosities. Chambered nautiluses were considered to be masterpieces of nature, but they were still something that man could improve on. Just as Noble Pen Shells were displayed alongside articles woven from sea-silk, complete nautilus shells were arranged next to crafted nautilus cups, encouraging viewers to contemplate nature’s raw materials and the skill of the artisan who enhanced the shell’s beauty through carving and engraving.

  The museum’s collection includes several more nautilus cups. The Burghley Nef is a French sixteenth-century salt cellar, crafted from a nautilus shell into a medieval sailing ship propped up on a silver mermaid; there is a sixteenth-century cup from England with a golden sea monster opening its ferocious jaws and poised to engulf the tiny figure of Jonah (the original nautilus shell was lost and is now replaced with a silver facsimile); a Polish nautilus shell clasped in an extravagant gold mount and covered with engraved glass and gemstones is dated to 1770.

  All of these nautilus shells were probably imported from Indonesia by Dutch merchants aboard some of the same fleets that carried billions of Money Cowries from the Maldives to exchange for slaves in West Africa. These global trade routes supplied an enormous demand for exotic objects from faraway places, including many varieties of seashell.

  In auction houses across Europe throughout the eighteenth century, shell mania took hold as rich collectors paid exorbitant prices for rare and beautiful specimens. By the beginning of the nineteenth century, cabinets of curiosities were gradually being replaced by more orderly, systematic collections of natural history objects kept by people who knew what they were looking at. While most collectors didn’t stray further than the auction rooms, there were those who aspired to go on much greater adventures. At around the time that Jeanne Power was embarking on her studies of argonauts and their shells, another unsung pioneer of natural history was setting out to pursue an eccentric dream. Hugh Cuming spent years on a series of intrepid adventures on the high seas, risking his life in far-flung lands, and all because he wanted to collect more seashells than anyone ever had before. He brought thousands of shells back from his global journeys; they redefined the boundaries of species diversity in the natural world.

  One of the strongest connections many people feel to seashells is the urge, now and then, to collect them, and it’s a time-honoured hobby. One of the oldest known shell collections was preserved in the Roman city of Pompeii. When Mount Vesuvius erupted in 79 ad, it choked and buried the city and its inhabitants in ash. Inside one excavated house, archaeologists found a gathering of shells that came from distant seas, certainly as far as the Red Sea, and they seem to have been kept for the simple reason that they looked pretty.

  Anybody who has visited a beach has probably spent time idly browsing the shoreline, poking through flotsam and jetsam, to see what the sea has pitched up. Beautiful, spiralling shells are no doubt among the greatest of beachside treasures. They appeal to the hoarder in us all, the part of us that wants to have and keep things, especially those mementos that remind us of a different place and time, of holidays and sea breeze and sand between our toes.

  Then there are people who take shell-collecting much more seriously, the ones who get infected with the need to hunt down new things, to write lists and keep scores. The thrill of discovery was probably what drove Hugh Cuming to do what he did.

  As a young boy, he explored the beaches of south Devon, on the heel of England’s south-westerly foot that points towards France. He was born five miles inland, at the end of a winding estuary in a hamlet called Dodbrooke, on St Valentine’s Day, 1791. His siblings were Jane, Thomas and James, Richard and Mary were his parents, and little else is known about Cuming’s early home life. He was only one when his father died, and by his teens he was apprenticed to a local sailmaker, where he learnt a profession that would eventually lead him to the other side of the world. For now, though, Cuming stayed close to home, where he may well have encountered a trio of men who lived nearby: a ma
gistrate, a colonel and a shoemaker. All three were adventurers in their own way, and together could have shown the young Cuming what possibilities the world had to offer if you just went to look for them.

  The first of these men was Charles Prideaux, a gentleman who lived most of his life in a fine, stone-fronted house smothered in vines in the centre of Kingsbridge, a town near Dodbrooke. Prideaux was a magistrate, but his heart lay in the natural world, as it did for many others of his generation. He belonged to a clique of amateur naturalists that swelled in number greatly during the eighteenth century. For those with a little spare time there was no better hobby than gathering fascinating and beautiful objects from the natural world. Prideaux was especially enchanted by animals with shells. He made grand collections of seashells and crabs, and developed a special fondness for bizarre creatures that combine the two – the hermit crabs – including several new species that were named after him. It’s not known whether Cuming ever met Prideaux, but he may have heard stories of the ardent naturalist rowing out into Plymouth Sound and lowering a small wooden dredge into the depths to bring back hidden wonders from the seabed.

  Cuming seems to have made a personal connection with another local naturalist. Colonel George Montagu retired from a long army career to live in Kingsbridge, where he wrote books about birds and molluscs, including hundreds of species that he spotted in Britain for the first time. According to several accounts, Montagu took the young Cuming under his wing, encouraging him to explore the Devon coast and start his first shell collection.

  There was one other Kingsbridge man who may have inspired Cuming to pursue more exotic adventures. Compared with the other, wealthier naturalists, Cuming had more in common with John Cranch. Both Cranch and Cuming were sent at a young age to learn a trade – Cuming made sails and Cranch shoes – and both of them turned out to have an adventurous spark.

  John Cranch was desperate to become a full-time naturalist. He worked hard at his Kingsbridge shoe business to make ends meet, but escaped whenever he could to sea. He assisted Colonel Montagu, often accompanying him on dredging trips offshore. He wrote articles and papers about his findings and discovered new species that were named in his honour.

  In 1816, after his friend William Leach at London’s British Museum put in a good word for him, Cranch was taken on as the zoologist on a Royal Navy expedition to find the source of the River Congo. The voyage got off to a bad start when the brand new, 30-tonne, 20-horsepower steam engine only propelled the vessel at three knots, barely faster than strolling pace. The paddle wheel and engines were stripped out, and HMS Congo finally cast off under sail power. On the way to Africa, Cranch gathered zoological specimens, including the living argonauts that would later bear his name. When they eventually reached what is now the coast of the Democratic Republic of Congo, the ship only made it a few hundred miles inland before impassable waterfalls and rapids blocked their way. The only thing the crew discovered about the origins of the Congo River was that the only way to find it would involve a lot of walking. They struck out overland on foot but a terrible illness soon broke out, probably yellow fever. Cranch fell ill, and for 10 days he was slung in a hammock and carried back to the ship where he soon died, along with more than half the crew.

  Shortly before grim news of the Congo expedition filtered back to England, Colonel Montagu met a far less exotic but equally fatal demise. He stepped on a rusty nail at his house in Kingsbridge and died of tetanus; staying at home or exploring faraway lands, either way life was precarious at the start of the nineteenth century. It is easy to imagine which of the two fates Hugh Cuming would have wished on himself, if he had had to take his pick, because he soon set off on overseas adventures of his own. In 1819, aged 28, he left Devon for the first time and set sail for the southern hemisphere to take a job as a sailmaker in Valparaiso, a major seaport on Chile’s mid-west coast, where a new British colony was growing fast.

  Life went well for Cuming in Chile. He met Maria de los Santos, who he never married but their daughter, Clara Valentina, was named in honour of her father’s birthday. In his spare time, Cuming scoured the rocky shores and inlets around Valparaiso, and began to amass a considerable collection of shells that were new to him. Both his work and his hobby introduced him to various local characters – port inspectors, customs officers, bureaucrats and fellow shell collectors – who would prove to be immensely helpful in the years to come. It was one of them, a Lieutenant John Frembly, who announced Hugh Cuming to the scientific world in 1825 when he described a new species of chiton.

  ‘I have named this species after my friend Mr Cumings,’ wrote Lieutenant Frembly. He went on to speculate that Cuming would ‘soon make a large addition to our present stock’. He may have misspelled his friend’s name but Frembly was not wrong in his hunch that there was much more to come from this enthusiastic collector. It would take a few years for the world to find out just how substantial Cuming’s contribution to shell-collecting and science would be.

  Cuming had done very well as a businessman in the short time he had lived in South America, and by 1826, aged only 35, he had built up enough savings to retire and devote himself to chasing a grand ambition. Cuming built a small wooden schooner, decking it out with collecting kit and ample storage space. It was probably the world’s first custom-made vessel devoted to scientific research. He hired the services of a Captain Grimwood, and on 28 October 1827 the two of them cast off the ropes of the Discoverer, waved goodbye to Maria and Clara, and set sail due west to see what they could find – including as many shells as possible.

  By the time Cuming and Grimwood sailed into the Pacific, a new age of scientific discoveries was well underway. Up until the turn of the eighteenth century, explorers travelled the world mainly to try to acquire and expand colonies and to open up new trade routes. Political and economic ambitions never went away, but they were joined by a growing scientific curiosity guided by a new fellowship of scientists. Professional societies were forming in cities across Europe, and they were the driving force behind many great expeditions; scientists became indispensable members of the crew.

  Captain James Cook was hired by the Royal Society in London in 1768 to sail to the Pacific Ocean to observe the transit of Venus across the face of the sun. On board with him on HMS Endeavour were the naturalists Joseph Banks and Daniel Solander, who were in charge of gathering plant and animal specimens along the way, including a lot of seashells. Solander was one of 17 young adventurers recruited by Carl Linnaeus to join expeditions around the world, to collect specimens and test out and expand his new binomial formula for naming species (giving them a two-part name, first genus then species, as in Homo sapiens). Collecting animals and plants and cataloguing them according to Linnaeus’s new scheme became a major goal of eighteenth-century exploration, and many global voyages returned with hoards of natural history specimens. The French ships La Boussole and L’Astrolabe set off in the 1780s with the aim of completing Cook’s exploration of the Pacific, but they both vanished without trace in the Solomon Islands. Numerous voyages attempted to locate the Northwest Passage that was believed to connect the Atlantic and Pacific by a northerly route; other trips made detailed observations along the coasts of India, China and Australia.

  All these globetrotting efforts helped uncover a simple and powerful truth about the natural world’s biological riches: they showed that patterns of life vary across the globe. In order to find new varieties of plants and animals, simply go and look carefully in places no other scientists have been before. New places: new species.

  The findings of the early scientific expeditions, Cook’s voyage in particular, no doubt gave Hugh Cuming the idea of sailing across the Pacific in search of new and unknown shells. What set Cuming and Grimwood apart from other collecting expeditions at the time was the small scale of their mission. It was just the two of them. There was no big ship filled with provisions and a permanent, supporting crew on hand, and no money from government or scientific societies; just Cu
ming’s private funds, and the hope that when he got back he could sell some of his shells while keeping the best specimens for himself.

  For eight months, Cuming and Grimwood island-hopped across the Pacific on board Discoverer. Cuming chronicled their voyage in a journal, of which a copy survives (he probably wrote it up on his return to Chile). It traces their route, and offers glimpses into the other adventures they had along the way besides shell-collecting.

  It took them a week to sail 400 miles to their first stopping-off point, the Juan Fernandez Islands, famous as the home of castaway Alexander Selkirk, the inspiration for Daniel Defoe’s Robinson Crusoe. Selkirk was rescued 100 years before Cuming and Grimwood called in; unlike Selkirk’s three years of isolation, they stayed for just a week. During that time Cuming got his collection underway and he had already found some shell species that were different from those he knew from the Chilean coast. He also noted an abundance of goats left behind by visiting sailors and pirates, and lush vegetation with fruit and vegetables introduced from Chile, including ‘radishes of an extraordinary size’.

  The Discoverer next called in at Easter Island, where Cuming began his collection of anthropological artefacts, bartering cotton handkerchiefs for small wooden idols carved by the locals. He had brought with him a stock of tobacco, wine and colourful ribbons, which he exchanged throughout the voyage for traditional weapons and musical instruments; he was especially fond of his two nasal flutes. Throughout his journal, it is clear that Cuming was fascinated by people and places; he goes into great detail on the local costumes and practices, buildings and food. On Easter Island Cuming found more shells, saw the monumental moai statues, and stocked up on fresh provisions before heading onwards into the Pacific.