The Tomb of the Mili Mongga: Fossils, Folklore, and Adventures at the Edge of Reality

Also available in the Bloomsbury Sigma series:

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Suspicious Minds by Rob Brotherton

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Soccermatics by David Sumpter

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The Planet Factory by Elizabeth Tasker

Seeds of Science by Mark Lynas

The Science of Sin by Jack Lewis

Turned On by Kate Devlin

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Clearing the Air by Tim Smedley

The Contact Paradox by Keith Cooper

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Sway by Pragya Agarwal

Kindred by Rebecca Wragg Sykes

First Light by Emma Chapman

Models of the Mind by Grace Lindsay

The Brilliant Abyss by Helen Scales

Overloaded by Ginny Smith

Handmade by Anna Ploszajski

Beasts Before Us by Elsa Panciroli

Our Biggest Experiment by Alice Bell

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Fire and Ice by Natalie Starkey

Sticky by Laurie Winkless

Racing Green by Kit Chapman

Wonderdog by Jules Howard

Growing Up Human by Brenna Hassett

Superspy Science by Kathryn Harkup

The Deadly Balance by Adam Hart

Into the Groove by Jonathan Scott

The End of Eden by Adam Welz

For Umbu

And for Ben Collen and Georgina Mace,

who I hope would have chuckled if they knew I was writing this book.

Contents

Prologue: Anselm and Gaunilo

Chapter 1: Splendid Isolation

Chapter 2: Sumba, East of Java

Chapter 3: Glutton-Granny

Chapter 4: Storytelling

Chapter 5: Rodents of Unusual Size

Chapter 6: Tulang Junkie

Chapter 7: The Wall of the Mili Mongga

Chapter 8: An Interlude with Giant Rats

Chapter 9: The Island of the Day Before

Chapter 10: They Might Be Giants

Chapter 11: The Perfect Island – A Fairy Tale for Biologists

Acknowledgements

Notes

Index

Sir, I invite your highness and your train

To my poor cell, where you shall take your rest

For this one night; which, part of it, I’ll waste

With such discourse as, I not doubt, shall make it

Go quick away – the story of my life,

And the particular accidents gone by

Since I came to this isle.

William Shakespeare, The Tempest

Well, that’s how history’s written, isn’t it?

Marcel Proust, In the Shadow of Young Girls in Flower

(after a quote by Voltaire)

PROLOGUE

Anselm and Gaunilo

The universe is full of magical things patiently waiting for our senses to grow sharper.

Eden Phillpotts, A Shadow Passes¹

The only part of a story that is true is the part the listener believes.

Hermann Hesse

Matius and Yakobus were back from church and already waiting when our car pulled up in the village. They opened the door and squeezed in, somehow making room on the back seat of the already-packed vehicle. Resting his parang between his knees so that the blade pointed downwards, Matius smiled broadly at us, his teeth stained a deep red. Following directions from the two men, we turned down a dirt track at the edge of the village, stopping briefly for Matius to jump out and run up to a shack with a corrugated metal roof to buy cigarettes and sirih pinang for the day’s hike. Bob Marley blared from the car stereo as we bounced along the dusty track, until Matius called out for us to stop as we neared another hut with thin walls made of plaited cane. High above, a sea eagle circled over the dry landscape.

We set off on foot along the valley behind the hut, walking past an abandoned rice paddy and mounds of dry goat dung. As I pushed my way through tall grass that reached to my shoulders, a pleasant minty smell rose up from the vegetation, and a huge, bright yellow butterfly as big as a bird beat its way lightly past me. After a while, when we had crossed a small stream, the path entered the forest. Here the air was still, except for the hum of insects and an occasional faint wind, with the silence broken only by the rhythmic crunching of our feet on dead leaves. Sweat ran down my back. The path turned uphill and became indistinct, and we clambered onward over sharp rocks sticking up from the forest floor. The hill was increasingly steep, and the heavy sounds of my laboured breathing filled my ears. Suddenly, we had made it; the trees were behind us, and we were through to a grassy clearing on the ridge of the hill. Looking back the way we had come, over the dry forest now spread out below us, the sun caught on the tiny steep metal roofs of the village in the distance. I pulled the dusty plastic bottle from the side pocket of my rucksack and drank down a long, refreshing draught of lukewarm water. Ahead, the dry hills stretched on to the horizon, with scrappy patches of forest clinging to the valleys that dropped down from either side of the ridge. I offered my bottle to Umbu. He looked at me. ‘I don’t need water.’ The serious expression on his face changed into a conspiratorial grin. ‘I just need bones!’

The trail followed the ridge, heading towards a large solitary coconut tree in the far distance. The grass on the hilltop was sun-bleached, dead, white; the soil was grey and ashy. There was no colour anywhere, except for a pale yellow tinge to the plants growing on the lower slopes of the hill. A few clouds drifted far above us, disinterested. Bee-eaters perched in the tops of dead trees sticking out of the side of the ridge. We walked silently in single file past an old, dug-out grave. Heat tightened around my head like a band.

On the long drive back to Waingapu the previous evening, after we had spent the day talking to the villagers about the purpose of our visit, I sat in the car shelling peanuts contemplatively. The light drained from the landscape as the sun set, leaving the world outside the car flat and ghostly. Somehow, exploring an ancient abandoned graveyard felt worse on a Sunday. But the story that Matius and Yakobus had told about what they’d seen was too tantalising to ignore. Would this finally provide the answer to the mystery we’d heard so much about throughout our time on Sumba?

At the head of the line of walkers, Matius suddenly dipped off the ridge down the side of the hill on our right, leading us back into the forest. There was no path now, just snags and rocks and potholes, but after the heat of the hill it was refreshingly cool and dark under the trees. There were new sounds here, tinkling and bubbling above us, the birds making these calls themselves unseen. The forest floor was made of boulders of ancient coral rubble, attesting to the antiquity of the landscape we were hiking through and the changes it had experienced across gulfs of time too great to imagine. A new trail emerged between the rocks, and we pressed on under huge trees. I stepped over dry brush, ducking under branches and vines as thorns snagged at my arms. These were hornbill trees, Matius said; the forests behind the village still contained 10 pairs of the rare species of hornbill that was only found on Sumba, and they needed massive trees like these in which to nest and roost.

I clambered over dry brown lianas wrapped around a low overgrown stone wall, the entrance to the long-abandoned old village in the forest. Inside the wall, the floor was made up of broken slabs of ancient graves. Anxious bird calls, bouncing back and forth to each other in the trees, rose to a crescendo. Matius yelled out in amusement – a megapode scampered low across the trail in front of him, disappearing off to the right. Thin saplings grew up through the grave rubble. Some of the tombs were still upright and intact between the trees, like huge stone dinner tables on massive pillar legs, covered in dry curled leaves. A line of ants marched over the surface of the nearest grave. Ritual cupmarks were carved on the capstone where sirih pinang could be left for the dead to chew. A hornbill called from somewhere far off through the forest.

Under the cool trees, I walked past a jumble of broken slabs from damaged tombs. How old was this rubble of time? Suddenly there was a shout from up ahead. Matius placed the coils of rattan that he was collecting from the forest down on a capstone. Umbu ran over and stood next to Yakobus. ‘Pak Sam!’ Umbu called to me. ‘The bones. They are here.’

In 1078, an abbot named Anselm from Bec, an eleventh-century centre of learning in northern France, put forward what is now considered to be western philosophy’s first ontological argument – an argument that aims to prove the existence of God. Imagine the greatest being you possibly can, Anselm proposed. Even if you don’t believe in God, such an entity can still exist in your mind. But if you can conceive of such an imaginary being, then an even greater being must be possible. Existence is perfection, Anselm argued; so something that actually exists in reality is inherently greater than an imaginary version that exists merely as an idea in the mind. Ergo, concluded Anselm, this is evidence for God.

Anselm’s argument constituted robust and challenging logic in the eleventh century. He went on to become Archbishop of Canterbury and was then made a saint, and his ontological argument became the subject of fierce debate – did it really provide irrefutable proof of God’s existence? Not everyone agreed, even at the time. Soon after Anselm laid out his theological proof, another religious thinker, a French Benedictine monk called Gaunilo, responded with a criticism called In Behalf of the Fool. Gaunilo considered that Anselm’s logic leads to the conclusion that many things exist which certainly do not, and he picked apart his argument by parodying it with another thought experiment. Instead of the greatest being, try to imagine the most perfect island, challenged Gaunilo. If we can conceive of such an island paradise, it must – by Anselm’s reasoning – therefore also exist in reality, as an existing island will by its very nature be more perfect than an imaginary one.

Did Gaunilo’s counter-argument fatally undermine Anselm’s ontological proof for the existence of God? Anselm himself didn’t think so; the debate rumbled on through the centuries, and ultimately helped to shape the course of modern philosophical thinking. In retrospect though, this medieval disagreement around the thorny question of what constitutes valid evidence of God raises very different points of interest. This was an argument of paramount importance throughout the Middle Ages and beyond – but it feels incongruous, even alien, to the types of reasoning that we now use to interpret the world around us, and even to what constitutes a meaningful question for many of us. Who today would think to base a logical argument around the ‘irrefutable’ premise that existence constitutes perfection? Thinking about Anselm’s supposed proof makes us aware of the extent to which our worldviews and perspectives differ from those of other peoples – both the societies that existed in the past, and also potentially the cultures that still exist in other parts of the world today. Are any of these modes of thought, these differing assumptions about reality, actually closer than any others to some sort of objective ‘truth’? And can we ever even manage to comprehend and see beyond the paradigms of the specific time and place in which we find ourselves?

But Gaunilo’s critique also raises the fascinating possibility of something that has been overlooked through the centuries by the various protagonists involved in this ontological debate. His thought experiment was intended to be absurd. But what if there is actually a perfect island out there somewhere? What might such a place be like, in imagination and in reality? And if you could find it, somewhere out there over the horizon, what would be waiting to greet you when you arrived? Might you end up finding evidence for God – or something even more strange? Or would its fantastic inhabitants turn out just to be imaginary after all?

To a biologist, all islands might be considered perfect. These isolated, fascinating places have set the scene for evolution to run wild in strange new directions and produce some of the world’s most unexpected and remarkable biodiversity. Or at least these island ecosystems used to be perfect, until people came along.

This book is about my explorations of an island on the other side of the world, to try to understand what kinds of unique species used to inhabit its remote landscapes, and what happened to these now-vanished animals. But it isn’t just a story about biology or biologists, even though I thought it would be when I started out on my adventure. There’s plenty of science and natural history in the pages that follow, which can hopefully also serve to illustrate the steps through which knowledge accumulates and science progresses; how sources of inspiration might be unexpected, requiring new leads to be followed in unplanned directions when confronted with things that we can’t easily rationalise or comprehend; and how possible explanations for our observations are often competing and hopelessly confusing. What are the different types of evidence we need to consider in order to reconstruct both the present and the past? And how can we understand the truth – indeed, what does this even mean, and is it ever really possible to achieve? What began as a study into biodiversity, fossils and extinction had to take on other intellectual frameworks and appreciate very different cultural perspectives. It also became a wider story about how people interpret the world around them – how they understand nature, ancient remains and traces from the past, other people and peoples, and even themselves – and how we can’t presume that there is just one obvious, intuitive way of doing this. Just how subjective and relative are our shifting worldviews – between individuals, across cultures, and through history? And ultimately, what do you do when you learn about things that can’t possibly be true?

In The Adventure of the Sussex Vampire, one of Arthur Conan Doyle’s final Sherlock Holmes stories (and one with its own ‘mixture of the modern and the mediæval, of the practical and of the wildly fanciful’), Holmes famously informed Watson about the case of the giant rat of Sumatra, ‘a story for which the world is not yet prepared’. My story is about giant rats on another Indonesian island, along with lots of other things that might either be real or not, or maybe somewhere in-between, and for which I don’t know if I was really prepared. You might even say, if you really wanted, that this is a story about stories – a true fairy tale. Although that might be taking it just a bit too far.

Note

1 This quote is usually attributed to W. B. Yeats, and is thought to describe Yeats’ vision of a supernatural world rich with unknown possibilities on the edge of human perception. In fact it is by Eden Phillpotts, an English novelist from the early twentieth century, and refers to the power of progressive scientific investigation to discover what was previously unknown – a completely opposite intent. This confusion over both origin and meaning makes it an appropriate quote with which to start this book.

CHAPTER ONE

SPLENDID ISOLATION

Strangely, from your little island in space, you were gone forth into the dark, great realms of time, where all the souls that never die veer and swoop on their vast, strange errands. The little earthly island has dwindled, like a jumping-off place, into nothingness, for you have jumped off, you know not how, into the dark wide mystery of time, where the past is vastly alive, and the future is not separated off.

D. H. Lawrence, ‘The Man Who Loved Islands’

Islands are powerful places. These little worlds, bound in and isolated by nature, and possessing an intangible, magical essence – where things are both familiar and somehow different – have provided fertile ground for the human imagination for as long as we have had poetry, literature and stories. An island, entire of itself, represents the world in miniature; these ‘tiny pieces of land, the existence of which imagination can just about hang on to’,¹ act as metaphors to provide new clarity about life when the details are simplified and stripped away. Free from the influence of the mainland, islands are stepping stones to other worlds. They inspire excitement and dreams of beguiling paradises, buried treasure and hidden secrets. They are lands of mysterious dangers and monsters. Their remoteness, isolation and simplicity have presented a primal challenge to marooned Robinson Crusoes and Swiss Family Robinsons, encouraging innovation and novel solutions to daily survival. They provide a fertile stage for experimentation, showing us alternate outward or inward realities and how these realities could be reached – from new models of political philosophy and how society might function to deeply personal revelation about identity, explored in solitude when the wider world becomes distant and its noise is quieted. Even the land underfoot is mutable and strange; it can be inundated by the waves or change unexpectedly into a kraken or aspidochelone, huge monsters that will drag the unwary down with them into the depths. We give islands our own meaning, with the specific flavour of different island narratives framed as fantasy, romance, allegory or satire, and addressing changing contemporary concerns of political expansion, exploration, colonialism or individualism. And from Gulliver to Pincher Martin, are the strange events experienced on remote islands even real at all?

The reasons that islands appeal so strongly to our imagination, and the ways in which they have been used in literature to explore differing aspects of the human condition, are mirrored in their importance for evolutionary science. For well over a century, islands have been recognised by scientists as being able to provide crucial insights into the processes by which new species are generated. Islands possess two key ecological characteristics that make this possible: isolation and simplicity.

All islands, by their very nature, are isolated in space by water barriers. This geographic isolation results in reproductive isolation: after a population of a particular species finds itself on an island, genes are rarely – if ever – exchanged through reproduction with individuals from the wider outside world, and genetic changes that might arise are not diluted out or modified. Instead, this genetic novelty may spread through the island population and become fixed in all of its descendants – either because it confers some specific environmental advantage, or simply as a result of mating within a small isolated population (especially if individuals are related). Populations of species that can move freely over both land and water, such as seabirds, are less affected by an island’s isolation; but even for these species, site fidelity to traditional nesting grounds means that distinct genetic lineages associated with different islands can still often develop.

In addition to isolation in space, the accumulation of genetic differences in island populations is also dependent upon another type of isolation – isolation in time. The amount of this second type of isolation that a population will experience depends upon the geological origins of the island where it lives. Although all islands are superficially similar to one another – basically, they’re all lumps of land surrounded by water – they fall into a series of distinct geological types associated with very different histories of isolation.

Islands with the shortest history of isolation are continental islands, which form part of the same continuous tectonic block of continental crust as nearby continental mainlands. These islands are only isolated by shallow seaways, which ebb and flow over time, and so periodically reconnect the islands to the mainland. Tidal islands, such as St Michael’s Mount in Cornwall, are reconnected every day to the mainland by causeways that emerge above water at low tide. Other continental islands such as the British Isles have remained isolated for far longer than recorded human history, but their island identity is still transient in geological terms. They have been reconnected repeatedly to the neighbouring continental mainland during numerous intervals of sea-level change over the past couple of million years, as the Earth has moved through Ice Age glaciation cycles driven by gradual variations in its orbit around the sun, which caused huge amounts of water to be periodically frozen and then released from the ice caps. At the moment we are in a high sea-level ‘warm phase’ of this cycle – the current Holocene Epoch of geological time, which commenced 11,700 years ago, and represents the period of broadly modern-day environmental conditions. However, as recently as 20,000 years ago during the preceding Late Pleistocene Epoch, the world was a much colder, drier place, with global sea levels lowered by up to 130m; in place of today’s wetter geography, continental islands were instead connected by exposed land bridges to the edges of the continents. The British Isles themselves were joined to what is now the Netherlands and Denmark by a low-lying landmass called Doggerland, which was only inundated by rising sea levels within the last 9,000 years. Such a recent history of isolation has left little time for populations of animals and plants found on continental islands to accumulate genetic novelties and become evolutionarily distinct from populations on neighbouring continents.

Other islands, such as Madagascar and the islands of New Zealand, are also composed of continental crust. However, these continental fragments or microcontinents have not been connected to continental plates for a very long time; they were ripped free by powerful tectonic forces during the distant prehistoric past and have followed adventurous geological journeys of their own ever since, propelled by continental drift to inch along in isolation over aeons of geological time. The last time that both Madagascar and New Zealand formed part of a larger continental landmass was when the supercontinent of Gondwana occupied much of the southern hemisphere and dinosaurs walked the Earth, allowing ample time for some isolated populations to die out and others to evolve into new species. Many of today’s vagrant microcontinents serve as the final refuges for evolutionarily ancient lineages that vanished long ago from other parts of the world – they have become museums of ancient biodiversity. For example, the tuatara of New Zealand superficially looks like a lizard (and was originally classified as such), but is in fact the only surviving member of an entire reptile order, the Rhynchocephalia, which first appeared around 200 million years ago and once contained a diversity of species found all over the world.

The third category of islands, oceanic islands, have never been part of a continent or continental shelf. Instead, they are formed by powerful underwater tectonic forces that push upwards and create new land in the middle of the ocean. Such islands are typically produced by volcanic activity, either along tectonic boundaries or at volcanic hotspots in the middle of tectonic plates. Some are several million years old, such as the north-western islands of the Hawaiian archipelago, while others have emerged from the waves within the past century. Because these islands have never been connected to a neighbouring landmass, the only way that animals or plants can reach them is via overwater dispersal. James Henry Trotter rode a giant peach to cross the Atlantic Ocean in Roald Dahl’s story; zoological Trotters might instead get blown overwater by a hurricane (if they are birds or insects), or arrive on handy rafts or mats of vegetation that have drifted into the open ocean (if they are reptiles, mammals, or other species generally unable to fly). Seeds and other plant propagules could be carried to oceanic islands by favourable oceanic currents or in bird droppings.

Overwater colonisation on a convenient ‘floating island’ may seem highly implausible, and it’s certainly a rare chance event. However, the older literature contains a surprisingly large number of reports of wild animals being accidentally transported from place to place in this way. Following the flood of the Mississippi River in 1874, observers in the Mississippi Sound noted that ‘For miles were seen logs, driftwood and patches of turf and soil floating out into the gulf, filled with live animals, which clung to their frail barques with the tenacity of shipwrecked mariners. Among the animals were seen rats, raccoons, possums, rabbits, alligators, and moccasin snakes, in uncounted numbers.’² A ship travelling from Cuba to Philadelphia in 1902 encountered a floating island with many upright palm trees on it about 50km from the island of San Salvador; when some of the crew rowed over to investigate, they found that it was carrying numerous monkeys, some of which reportedly ‘threw coconuts at them’.³ In 1825, a floating raft of vegetation that was washed down the Paraná River to the Iglesia de San Francisco in Santa Fe was carrying a jaguar, which leapt ashore and killed two of the church’s friars.⁴ Most incredible of all, a floating island in Bangladesh that travelled down a river to Chittagong in 1868 was reportedly carrying … a live Sumatran rhino.⁵ The animal, a female named Begum, was dragged out of some quicksand near the mouth of the river⁶ and sent to London Zoo in 1872, where she was described as a new species (now regarded as just a distinct northern subspecies of Sumatran rhino). She ended up living in the zoo until 1900, becoming the longest-lived captive rhino at the time.

There are even direct observations of successful overwater colonisations of new islands taking place in this manner. One of the best-known examples was witnessed in the Caribbean in 1995, when Hurricanes Luis and Marilyn swept past the island of Guadeloupe and uprooted a huge mat of trees and logs, which was carried more than 300km by powerful currents to the more northerly island of Anguilla. Clinging onto this raft of vegetation were at least 15 green iguanas, a species found on Guadeloupe but not Anguilla. Although they seemed weak and dehydrated, and some were injured, the iguanas were seen to climb ashore. The group of animals contained both males and females, and a population of iguanas descended from these founders still survives on Anguilla today.⁷

In practice, the differences between continental islands, microcontinents and oceanic islands aren’t totally clear-cut. Overwater dispersal can contribute to the diversity of all island types. Some geologically ancient islands, such as Jamaica and New Caledonia, are thought to have been largely or completely inundated by the sea at some point in time after breaking free from their parent landmasses. Despite their different geological origins, such islands therefore act functionally like oceanic islands, becoming clean slates for new fauna and flora to colonise after their original diversity was drowned, although they sometimes still also retain hardy surviving relict lineages alongside new arrivals. And some islands are actually hybrids, with different parts of their landmasses having formed via different geological processes. For instance, around 41 million years ago, a tiny fragment of what had once been Gondwana broke away from the edge of a larger piece of this ancient supercontinent, which had itself already broken free and reached the western Pacific. This continental fragment drifted eastward and ploughed into the volcanic islands of the Tongan archipelago, which had formed through tectonic uplift along a plate boundary, where it became incorporated into the otherwise volcanic island of ‘Eua. One of the reasons that ‘Eua was discovered to have a different geological origin to the rest of the Tongan archipelago was because it is the only island in the group that contains native podocarps, a type of coniferous tree that evolved on Gondwana during the early Mesozoic Era long before the supercontinent broke apart.⁸ These trees had unwittingly hitched a ride on the tiny scrap of continental crust as it drifted thousands of miles across the Pacific, to bear silent witness tens of millions of years later to the journey made by the bedrock beneath them.

Despite such complexities, this general framework of island types still helps us begin to understand how island animals and plants can be extremely distinctive and unusual, and how the level of differentiation they show depends upon the category of island they inhabit. To understand the generation of evolutionary novelty on islands more completely, we also need to consider the environmental conditions that exist on different islands.

As well as having been isolated for only a few thousand years, continental islands typically share very similar geologies, habitats and ecosystems to neighbouring continents. Essentially, they represent geographic extensions of continental environments, which just happen to exist on peninsulas that are periodically flooded. There is therefore rarely a strong evolutionary pressure for animals and plants on continental islands to adapt to unfamiliar environments, and they are very often unchanged in comparison to species on neighbouring continents. The British Isles have no endemic amphibian, reptile or mammal species (which evolved in situ and are found nowhere else), and only one endemic bird, the Scottish crossbill, which was until recently thought to be just a locally differentiated population rather than a fully distinct species. The rest of this island fauna is basically the same as that of northern France, with the exception of some species that have been historically eradicated in the British Isles (such as brown bears and wolves), and some that didn’t quite manage to colonise after the end of the last Ice Age cold period before the English Channel flooded again (such as black woodpeckers and white-toothed shrews).

Vagrant microcontinents were also originally connected to prehistoric continents, and shared species in common many millions of years ago. However, these islands have been isolated for considerably longer, and have also moved long distances via tectonic action, often into regions with markedly different patterns of temperature, rainfall, ocean currents, and other key regulators of local climate. The tectonic processes that have shifted these islands around the globe have often also modified their physical structure and created novel environments, from new geological landscapes such as mountain ranges, to changes in composition of the rocks that form soils and support plants. Even if ancestral populations of continental animals and plants were carried along with such islands as they rifted away from other landmasses, they will have had to adapt dramatically to survive. Newly formed oceanic islands also present strikingly novel environments for any species that find themselves washed up or