A cacophony of insect and amphibious reverberations echoed from the darkened edge of a primordial forest. Collective medleys of symphonic pitches filled the damp air, bringing this still night to life. A group of large herbivorous dinosaurs, Ceratopsians, huddled together to keep warm, guarding clutches of their freshly hatched eggs. Misty fog wafted from a bordering swamp and hugged the soggy ground, exposing only the massive heads and three horny protrusions of the gargantuan adults.
Most of their young lay in a deep sleep, insulated in leafy green nests and enclosed within a circle of these protective ten-ton matriarchs. This kept them safe from predation until morning, when large carnivores typically emerged from the dark cool of night, no longer fearing escape of their precious body heat.
The chirping and hissing ensemble was occasionally interrupted by the low resonating groan of a restless female, or by the distant call of an adolescent bull roving the nearby plain.
A pair of small furry creatures, resembling shrews or undersized possums, scurried along the circle’s edge, too insignificant to be noticed by the lumbering giants. Their noses were fixed to the soft earth, and within moments the smaller of the two furiously scratched the ground and extracted a succulent worm. Scooting and then weaving beneath the cover of oversized ferns, they emerged into the protection of moonlit growths waving on the neighboring flatland, and, climbing a termite mound, feasted on some protein-rich insects. This pair had been bonding for several weeks, and yet the ungracious male would soon abandon his burgeoning family and leave all parental responsibilities to the smaller and weaker female.
They were a couple of Earth’s primal mammals, resembling today’s monotremes, the egg-laying marsupials of present-day Australia. Once abundant in number, these diminutive animals, and indeed all the world’s few remaining mammals, were tonight teetering on the brink of extinction.
Their ancestors, the cynodonts, had first appeared on Earth long before this fateful evening, almost 240 million years ago at the beginning of the Triassic Period, about the same time as eoraptor, one of the earliest of dinosaurs. Then for millions of years, both mammals and dinosaurs proliferated, each giving rise to an abundance of uniquely adapted species. The virgin development of warm-bloodedness, inherent in both primitive classes, had proven a definite advantage in their savagely competitive world, often pitting select species of the two emerging groups against each other to battle for the same ecological niche. To further increase such fierce competition, all seven of the world’s continents had joined to form one giant landmass—the supercontinent of Pangaea—thrusting every animal on Earth into one giant arena and offering the weak no island on which to hide. This eventually allowed the fittest and best-adapted animals to dominate the entire globe.
It was upon that continental coliseum, toward the tail end of the Triassic Period, where the mammals began to disappear, decisive losers in the savage battle for planet Earth. Their numbers fell steadily, until only few scatterings of submissive species survived. Descendants of the eoraptors, on the other hand, had continued to proliferate and evolve, and eventually became many thousands of diverse species, their fossilized remains perpetually unearthed today. The variations of these dinosaurs were immense, and their domination lasted for the next 180 million years, throughout the coming Jurassic and Cretaceous Periods.
Although both mammals and dinosaurs had survived all three periods of Earth’s Mesozoic Era, the dinosaurs had clearly won the war, and by the time our small mating pair scampered the night’s moonlit brushes, the prospect for the ever-struggling mammal had shrunk to hopelessly grim. It was on this late-cretaceous evening, about sixty-five million years ago, that an unforeseen event would at last determine the future of all life on Earth.
The planet’s climate had already been changing. The creation of new seas, volcanism, and the formation of expanding mountain ranges had contributed to the latest eruption of evolutionary adaptations. The single supercontinent had again broken apart: first into the two large continents of Laurasia and Gondwana, and by this fateful night into the seven landmasses resembling the Earth of today.
The two tiny mammals wandering this dim field had few advantages in their ever-changing world. Possessing a brain-to-body ratio greater than any typical dinosaur was of little benefit when pitted against the numerical magnitude and overwhelming size of their prolific rivals. In addition, this diminutive pair tread unthreatened in the cool dampness of night, as soft hair and a layer of fat insulated against a loss of body heat inevitable without the sun’s warming rays.
And most strangely of all, their greatest advantage may have been their burrowed dens and nocturnal habits, protecting them from the multitude of carnisaurs roaming their primeval days. Forced to sleep in their underground tunnels for much of the day before emerging in the dark protection of night, these insignificant animals eked out a measly existence, subservient to the plethora of dinosaurs ruling every niche of their lush planet.
Feeling safe under the cover of darkness, the engorged little female mischievously bit the male on his hairier rump and waddled away toward the forest’s edge, fully expecting a playful chase. Chirping and squeaking while wrestling through wavering reeds, she employed this foxy behavior to lure him toward a closer bond. Then, scooting away once more, she gained a small lead before turning back to face her pursuing consort, allowing him to catch her and enforce his dominant role.
But she instantly froze in shock and disbelief as a swiftly moving shadow, several feet tall, darted out from behind a neighboring tree and snatched her mounting playmate in its sharp claws!
Loud and horrific screeching cries startled even the normally indifferent Ceratopsians, many raising their horny heads off the peat-covered earth. A snarl rose above the shrieks of agony and despair, compelling the female to jerk backward. Promptly, two additional shadows sprinted from behind the first and ran directly toward her, snarling warm breaths. She turned and ran feverishly, but the demonic figures gained on her. A sharp pinching pressure on her rump fired a surge of energy through her tiring muscles, provoking a jolt enough to gain an additional second. She darted through the hollow core of rotten log and quickly through the circle of nesting triceratops, who, unaware of her meager retreat, initiated a chorus of loud groans in the direction of the charging demons.
Unable to follow through the wall of guarding mothers, the two predators turned back to their feasting pack-mate, tilted their heads and screeched, hoping to intimidate the surrender of some warm flesh.
These were Troodons, a new type of dinosaur already adapting to the changing environment. Standing five feet tall and weighing nearly ninety pounds, these highly advanced hunters retained many features that had made prior members of their class so successful—legs directly below their torsos, whiplike tails for balance, sharp serrated teeth, and bipedalism to free their hands for grasping.
But several new characteristics had also evolved in these viable creatures: larger and more forward facing eyes enabled them to see better in the dark and enhanced their depth perception. Opposable fingers on their highly dexterous three-digit hands held and manipulated prey more efficiently. Patches of downy feathers retained the evening’s warmth; and lastly, brains weighing one and a half ounces, so large that they left convoluted impressions on the fossil remains of their skulls, evolving gray matter too fast for the bony cases protecting them. These new warm-blooded omnivores were so intelligent that they possessed a brain-to-body ratio six times greater than the average dinosaur, and even better than their clever little mammal prey.
They were clearly the most intelligent animals the Earth had ever seen. Already far advanced, these predators stood poised to take the next evolutionary leap toward truly intelligent life.
With a pounding heart, rapid breathing, and a frantic glycogen release, the furry little widow hurried into the safety of her subterranean den, too frightened to notice that the nine eggs she had left underground had all hatched in her absence. As she lay back trembling, the underdeveloped hatchlings fought their way to the warmth of her pouch, hungry to lap up the sweetly sebaceous secretions poised to ooze from her underbelly. It would be several hours before the nurturing of her offspring would calm her nerves and allow her to sleep throughout the next day, her warm belly full and nestled in her buried haven.
As dawn approached and the night’s black horizon lightened to a starry blue, the cocky Troodons headed for the cover of the fern-infested forest, hoping to trap another insectivore. Hunting seemed so easy to these inventive creatures, and each envisioned a return to the savanna to digest the spoils of this pre-dawn rampage, ready to bask in the rays of Earth’s yellow sun.
But suddenly, out of the blue, a blinding flash on the horizon turned their heads toward the southeastern sky, where a strange thunder soon rumbled from the ground, and several minutes later an equally persistent rumble in the skies.
Every living being stood mesmerized as unprecedented vibrations shook the air and earth with an encompassing, trembling momentum, sometimes subsiding before resurging and rustling leaves from the treetops again. Finally, after what seemed the longest and most persistent rumble of all, it ended. Tranquility returned. For the first time in millennia, an eerie quiet abounded, neither a sound nor motion was perceived. The air stood static; insects lay motionless in their hives.
The warm rising sun soon cleared the cloudless skyline, and a bright, sunny day was in plain sight, restoring calm among the herds. But that calm quickly evaporated, replaced by utter global carnage, for an epic event had just unfolded that was destined to deflect the evolutionary development of the planet in a direction ostensibly impossible just a minute prior.
It was fifteen hundred miles to the southeast where a five-mile-wide asteroid had penetrated the atmosphere and slammed unabated into the coastline of a large gulf: two-dozen tons of metal traveling at over thirty miles per second. A sonic boom was the first indication to those unfortunate animals directly below; an explosive shock wave as the metallic mass forced its way through the stratosphere.
A faint whistling followed: an eerie pitch that grew deafening as the intrusive object rubbed miles of air and ignited from friction before striking the planet with a second thunderous bang.
This stray piece of space debris may have once been part of another planetary arrangement, a starry satellite in a distant solar system, and yet now, after wandering the abyss of space for millions of years, had been attracted by the gravitational pull of our system’s yellow sun. It would have certainly vaporized in the star’s corona had the diminutive Earth not been revolving directly in its path.
This tiny space rock, rich in the otherwise rarely found elements of iridium and platinum, instantly redirected the course of all future life on Earth. Hitting with a force of one hundred million megatons, many times greater than the combined nuclear arsenals of the entire developed world, this cosmic intruder created a blast-wave hotter than the sun and left a crater a hundred miles wide, triggering a wildfire of cinder-laden ash that infiltrated the entire atmosphere to disintegrate the forests of the world, consuming oxygen while cooking every living thing in its path and raising worldwide surface temperatures to two hundred degrees Fahrenheit for days. A series of earthquakes and volcanoes erupted for weeks, devastating local environments and triggering mega-tsunamis: tidal waves nearly a mile high. Five million tons of rock and ash were ejected into the air and propelled a plume of vaporized dust and steam halfway to the moon before it cooled in space and fell back to Earth as a blanketing dark cloud that blocked effective penetration of sunlight for years to come. This encompassing stratus precipitated acid rain for months and spawned a nuclear winter that may have lasted a century. After weeks of ravaging and inescapable fires, average global surface temperatures abruptly ranged near freezing.
With this inescapable darkness and shocking climatic change, life on Earth had been deflected on a new tangent. The food chain collapsed and a mass extinction, common in Earth’s long history, again wiped out the world’s dominant species—including every living dinosaur.
Evidence of this catastrophe survives today. A crater dated to the fateful event survives just off the Yucatan Peninsula on the coast of Mexico, with a characteristic tektite melt spreading from its center. And even more telling than that spewing of natural glass is a thin layer of the extremely rare earth elements of iridium and platinum, common in asteroids along other trace metals, deposited around the entire globe in a mineralogical defining line that divides the Mesozoic from the Cenozoic Eras. These are the time periods that distinguish the Age of Dinosaurs from the Age of Mammals.
Of the warm-blooded species preceding this fatal disruption, only a few select birds and mammals survived, possibly due to their insulating fat, feathers, fur, or merely their isolation from the initial surface fires—debates will rage for decades. And despite birds still boasting a greater number of worldwide species, it was the descendants of those trifling mammalian hatchlings that have since inherited the Earth.
Insulated from the initial wildfires by feeding in their network of underground burrows; they soon emerged exclusively during the darker, colder days, and slept within the protection of warm dens in the pitch-black of frigid nights. Millions of years, and countless generations, has since shaped them into every subsequent species of mammal that has ever existed.
From that handful of furry monotreme siblings has evolved the aardvark, the zebra, the bat, the cat, the mouse, the blue whale (the largest animal ever to inhabit planet Earth), the elephant, the kangaroo, and the Homosapiens—the modern human being.
Could any sane thinker, observing this evening’s events just hours before its unheralded extraterrestrial encounter, have ever selected the frail hatchlings of the widowed mammal over the Troodons as the procreators of the only advanced intelligence ever to evolve on planet Earth? Saved from extinction by an encounter with this iridium-rich orb, it was the descendants of the mammal and not the dinosaur who would eventually build cities and malls, design computers and spaceships, and ultimately escape the gravity of Earth—destined to navigate the infinite pathways of space