by Cixin Liu
More than a thousand ants bustled about the dozen or so crevices and soon the scraps of meat had been picked clean. The dinosaur’s dental discomfort had been dealt with! The Tyrannosaurus was not yet evolved enough to say thank you, so it merely let out a long sigh of satisfaction. This sudden hurricane blasted every last ant out of the dinosaur’s mouth and into the air in a cloud of black dust, but because their bodies were incredibly light, they landed unscathed about a metre from the Tyrannosaurus’s head. With their stomachs now full, the ants pattered back to the entrance of their town, thoroughly sated. The Tyrannosaurus, meanwhile, rolled over into the cool shade and fell into an easy sleep.
And that was that.
As the Earth quietly turned, the sun slid silently towards the west, the cycad shadows lengthened, and butterflies and bugs flitted through the trees. In the distance, the waves of the primeval ocean lapped against the shores of Gondwana.
Unbeknown to all, in this most tranquil of moments the history of the Earth had taken a sharp turn in a new direction.
2
The Age of Exploration of the Dinosaur Body
Two days after the encounter between the ants and the dinosaur, on an equally sweltering afternoon, the inhabitants of the ant town were shaken by another quake. They scampered up to the surface and were met by the towering figure of a Tyrannosaurus, which they straightaway recognised as the same one from before. It had hunkered down and was scouring the ground for something. When it saw the colony, it lifted a claw and jabbed at its teeth. The ants understood immediately, and in a single uniform gesture all 1,000 of them waved their antennae excitedly. The Tyrannosaurus placed one of its forearms flat on the ground and allowed the ants to climb on. And just like that, the scene from two days earlier was replayed: the colony made a meal of the scraps of meat stuck between the dinosaur’s teeth, and the dinosaur was relieved of a minor dental discomfort.
For some time after that, the Tyrannosaurus routinely sought out the town of ants so they could pick its teeth. The ants could feel its footfalls from a kilometre away and were able to accurately distinguish them from those of other dinosaurs. They could even tell from the vibrations in what direction the Tyrannosaurus was moving. If it was heading towards the town, the ants rushed eagerly to the surface, knowing that their food supply for the day was assured. Even though one party in this cooperative endeavour was very large and the members of the other party were undeniably very little, it didn’t take long for the interactions between the two to become well honed.
One day the vibrations coming through the ants’ earthen ceiling sounded different, unfamiliar. When they streamed up into the clearing to investigate, they saw that their partner had brought along three other Tyrannosaurus rex and a Tarbosaurus bataar! All five dinosaurs gestured at their teeth, requesting the ants’ help. The mayor, recognising that its colony couldn’t possibly undertake such a massive task on its own, sent several drones post-haste to contact other ant towns in the area. Soon, three mighty rivers of ants came pouring in from between the trees, and an army of more than 6,000 ants converged on the clearing. Each dinosaur required the services of 1,000 ants, or, rather, the meat between the teeth of one dinosaur could satisfy 1,000 ants.
The next day, eight dinosaurs came to have their teeth cleaned, and a few days later that number increased to ten. Most of them were exceedingly big carnivores and they had a correspondingly big impact on their surroundings. They trampled the nearby cycads, enlarging the clearing significantly, and at the same time they solved the food problems of a dozen ant towns in the vicinity.
However, the basis for this cooperation between the two species was by no means secure. For a start, compared to the myriad hardships faced by the dinosaurs – hunger when prey was scarce, thirst when water sources had dried up, injuries sustained in fights with their own or other kinds of dinosaur, not to mention a host of fatal diseases – getting meat trapped between their teeth was a mere piddling inconvenience. Quite a few of the dinosaurs who sought out the ants for a teeth-clean did so out of curiosity or for a lark. Equally, once the dry season was over, food would become plentiful again for the ants, and they would no longer need to rely on this unorthodox method of sourcing their daily meat. Attending those terrible banquets in the dinosaurs’ mouths – so very like the gates of hell – was not something most of the ants relished.
It was the arrival of a Tarbosaurus with tooth decay that marked a major step forward in dinosaur–ant cooperation. That afternoon, nine dinosaurs had come to have their teeth cleaned, but this particular Tarbosaurus still seemed restless even after its procedure had been completed; one might even describe its mood as antsy. It held its forearm high to prevent the cleanser ants from leaving and with its other claw gestured insistently at its teeth.
The mayor in charge of that colony led a few dozen ants back into the Tarbosaurus’s mouth and examined the row of teeth carefully. They quickly discovered several cavities in the smooth enamel walls, each large enough to admit two or three ants side by side. In went the mayor, braving one of the cavities, and several other ants crawled in after it. They scrutinised the walls of the wide passageway. The dinosaur’s teeth were very hard, and anything that could tunnel through material as tough as that was indisputably a digger to rival the ants themselves.
As the ants felt their way forward, a black worm twice their size suddenly erupted from a branch passage, brandishing a fearsome pair of razor-sharp mandibles. With a click, it bit off the mayor’s head. A bundle of other worms then burst out of nowhere, divided the column of ants in the tunnel and launched a ferocious attack against them. The ants were too exhausted to defend themselves and in an instant more than half were slaughtered. Those that did manage to break through the encirclement raced past the black worms but quickly became disoriented in the labyrinthine passages.
Of the original crew, only five ants escaped the cavity, one of whom was carrying the mayor’s head. An ant’s head retains life and consciousness for a relatively long time after being separated from its body, and so, bizarre though it sounds – and how much more bizarre must it have looked – the disembodied mayor’s head was able to address the thousand ants still standing on the dinosaur’s forearm. In a meeting that was clearly far larger than a simple tête-à-tête, the bodiless head explained the situation regarding the Tarbosaurus’s teeth, issued a final command and only then expired.
A crack team of 200 soldier ants now marched into the dinosaur’s mouth and made straight for that first tooth. Though the soldier ants were skilled at fighting, the black worms were many times their size. Owing to their familiarity with the structure of the tunnels, the worms successfully checked the soldier ants’ attack, killing a dozen of them and forcing the rest to retreat.
Just as morale began to flag, reinforcements from another town arrived. These troops were a different type of soldier ant. Though smaller, they possessed a deadly power: they were able to deliver devastating attacks with formic acid. The fresh battalion surged into the tunnel, got into position, pivoted 180 degrees, aimed their posteriors at the enemy and ejected a fine spray of formic acid droplets. The black worms were reduced to scorched masses within seconds. Dark smoke poured from their remains.
Another detachment of soldier ants flooded in. They were also relatively small, but their mandibles were venomous – so venomous that a tiny bite could cause a black worm to twitch twice and drop dead. With the battle now in full swing, the ant army moved from tooth to tooth, rooting out the black worms. Acidic smoke leaked from every cavity. A team of worker ants ferried the corpses out of the dinosaur’s mouth and deposited them on a leaf in its palm. Soon the leaf was piled high with dead black worms, many of them still smoking. Several other dinosaurs gathered around the Tarbosaurus, looking on in amazement.
Half an hour later, the last of the black worms had been purged and the battle was over. The Tarbosaurus’s mouth was filled with the strange taste of formic acid, but the dental complaint that had troubled it for most
of its life was gone. It began to roar excitedly, sharing the miracle with all the dinosaurs present.
The news spread quickly through the forest and there was a dramatic spike in the number of dinosaurs visiting the ants. Some of them still wanted their teeth picked, but most came seeking treatment for dental ailments, because tooth decay was prevalent among carnivores and herbivores alike. On the busiest days, several hundred dinosaurs would congregate in the clearing, striding along carefully between great streams of ants. It was a bustling, prosperous scene. Accordingly, there was also a sharp increase in the number of ants who came to service the dinosaurs, and, unlike their patients, the ants, once arrived, rarely left. And so, what had started off as a normal-sized town exploded into a megalopolis of more than a million ants. It was called the Ivory Citadel and became famous as the first gathering place of ants and dinosaurs on Earth.
With the boom in business and the end of the dry season, the ants were no longer satisfied with scraps scavenged from between the dinosaurs’ teeth. Their clients began to pay for their medical services with fresh bones and meat. Since the ants of the Ivory Citadel no longer needed to forage for food, they became professional dentists. This specialisation led to rapid advances in the ants’ medical technology.
In the course of their anti-toothworm campaigns, the ants often travelled along the cavities to the roots of the dinosaurs’ teeth. At the junction of the teeth and the gums they found thick translucent pipes. When these pipes were touched, for example during combat, violent earthquakes would shake the dinosaurs’ mouths. Over time, the ants came to understand that stimulating these pipes caused the dinosaurs pain; later, they would call these structures nerves.
The ants had for a long time known of a certain two-leafed herb that could make their own limbs go numb – numb enough that they felt no pain when a leg was torn off – and that could also put them to sleep, sometimes for several days. They now applied the juice of this herb to the nerves in the roots of the dinosaurs’ teeth, and the consequence was that contact with the nerves no longer triggered earthquakes. The gums of dinosaurs with dental diseases were frequently septic, but the ants knew of another herb whose juice could promote wound healing. So they spread the juice of this herb across the ulcers on the dinosaurs’ gums, which closed up quickly.
The introduction of these two pain- and inflammation-reducing techniques not only enabled the ants to cure dinosaurs of toothworm infestations but also allowed them to treat other ailments not caused by the worms, such as toothaches and periodontitis. However, the real revolution in the ants’ medical technology was brought about by the exploration of the dinosaur body.
*
The ants were natural explorers, not out of curiosity – they were incurious creatures – but out of an instinctive urge to expand their living space. Every so often, while exterminating worms or pouring medicine onto a dinosaur’s teeth, they would peek into the abysmal reaches of its mouth. That dark, moist, interior world awakened in them a desire to travel into the great beyond, but fear of the attendant perils had always stopped them in their tracks.
The Age of Exploration of the Dinosaur Body was eventually ushered in by an ant named Daba – the first named ant in the recorded history of Cretaceous civilisation. After much preparation, Daba capitalised on the opportunity presented by a toothworm treatment and led a small expedition of ten soldier ants and ten worker ants into the dank depths of a Tyrannosaurus’s mouth.
Battling extreme humidity, the expedition began its traverse of the long narrow isthmus of the tongue. Tastebuds speckled the surface like a vast megalithic structure of slimy white boulders extending far into the gloom. The ant explorers picked their way between them. As the dinosaur opened and closed its mouth, light from the outside world streaked through the gaps between its teeth, flickering like lightning on the horizon and casting long, wavering shadows behind the tastebud megaliths. When its tongue squirmed, the entire isthmus rose and fell like a stormy sea, causing shifting ripples to appear in the megaliths. And every time the Tyrannosaurus swallowed, viscous floodwaters gushed in from both sides, submerging the isthmus and forcing the ants to cling to the tastebuds for fear of being swept away. It was the stuff of nightmares, but the dauntless ants patiently waited for the floodwaters to recede, then pressed on.
At long last they arrived at the root of the tongue. The light was much weaker there, barely illuminating the mouths of the two enormous caves before them. In one cave, a fierce gale howled, by turns sucking and then expelling the air, reversing direction every two to three seconds. There was no wind in the other cave, just a reverberant rumbling that rose from its invisible depths – a rumbling familiar to the ants from their time working on the teeth, but much, much louder, more like continual booms of thunder. This mysterious and terrible noise unnerved the ants more than the gale, so they decided to try the windy passageway. They would later learn that this was the dinosaur’s respiratory tract and that the scarily noisy passageway was its oesophagus.
With Daba in the lead, the expedition proceeded gingerly down the slick walls of the respiratory tract. When the wind was with them, they hurried forward several steps; when the wind was against them, it was impossible to walk, and they could only flatten their bodies and grip the wall tightly. They had not descended very far, however, before the tickle of their legs began to irritate the respiratory tract. With a slight cough, the dinosaur put an end to the ants’ first expedition. A hurricane of unimaginable force spiralled up from the bottom of the tunnel, sweeping the expeditioners off their feet and jetting them across the isthmus of the tongue at lightning speed. Some of them were hurled headlong into the dinosaur’s huge teeth, while others were blown straight out of its mouth.
Daba lost one of her middle legs in the failed expedition, but, unperturbed, she quickly organised a second attempt. This time she decided they would tackle the oesophagus instead. The preliminary stages went smoothly. The ants entered the oesophagus and began the long march down the seemingly endless and terrifyingly loud passage. Its creepy darkness was the least of their troubles, however, for the Tyrannosaurus had stopped beside a stream and now took a sip of water. The first the explorers knew of this was when they heard a great roar building behind them, a roar so loud that it rapidly drowned out the noise ahead of them. Daba immediately ordered the team to a halt, but before she could even begin to work out what was happening, a wall of water came cascading down the tunnel, hurtling past the ants, flinging them into its churn and propelling them at terrific speed all the way down the oesophagus and on towards the dinosaur’s stomach.
Dazed and disoriented, Daba landed heavily and sank into something pulpy. She paddled her legs as hard as she could in a desperate bid to escape the ooze, but she couldn’t move at all in the sticky substance. Thankfully, the floodwaters were still pouring down, thinning the slurry and tumbling everything around, so when things finally began to settle, she was able to float to the top. She had another go at walking. The sludge beneath her was soft and watery, but solid chunks of varying sizes and shapes bobbed along on the surface, making it possible for her to crawl from one to the other. She made slow progress, the slime sucking at her feet, but at last she reached the edge of the slurry pit.
Before her rose a soft wall covered in cilia about as tall as she was, like a strange dwarf forest; the stomach wall, in fact. She began to scale it. Whichever route she took, the cilia curled around her, trying to grab her, but their reactions were sluggish and they came up empty every time. Daba’s eyes had now adjusted to her surroundings and to her surprise she discovered that it wasn’t totally dark in there. A faint glow suffused the space, shining through the dinosaur’s skin from the outside world. In the light she spotted four fellow ants also climbing the stomach wall. She veered off to join them.
As they began to recover from the shock of their ordeal, the five ants stared down at the vast digestive sea from which they had just extricated themselves, mesmerised by the slow churn of the viscous mire
. Every so often a great bubble exploded – the source of that reverberant rumbling. When a particularly large bubble burst below her, Daba saw a thick, squat object break the surface and list slowly to one side. She recognised it as a lizard’s leg. Moments later, another massive, triangular object rose to the top. Its huge white eyes and wide mouth identified it as a fish head. Plenty more partially digested items followed, mostly either the bones and chewed-up remains of animals or the stones of wild fruits.
One of the ants beside Daba gave her a nudge, drawing her attention to the stomach wall beneath their feet. It was weeping clear mucus. The gastric secretions merged into rivulets that glistened in the faint light as they trickled down through the forest of cilia into the digestive sea below. Several of the ants were already coated in the juice. At first it simply made them prickle all over, but that soon intensified into a burning sensation not dissimilar to the aftereffects of a formic-acid attack.
‘We’re being digested!’ one of the ants shouted. Daba was surprised she could still distinguish her comrade’s pheromones from the pungent cocktail of strange odours in the stale air.
The ant was right. They were being digested by the dinosaur’s gastric juices, and their antennae were the first things to go. Daba saw that her own antennae had been half-eaten away already. ‘We need to get out of here,’ she said.