An Arms Race of Intellect

3 Million Years Ago

Over two million years, trap-building gravediggers - which at the time constituted one behaviorally (but not yet genetically) distinct subset of a more behaviorally varied species, not all of whom constructed traps - spread across Serinarcta. Their effect on megafauna was not insignificant, as their hunting success was often much higher than contemporary predators, and noticeable declines occurred in a variety of prey species as gravediggers became more abundant and set increasingly large numbers of traps. Furthermore, different lines of the species refined different trapping methods; in addition to the highly successful, traditional pitfall trap, gravediggers over many generations also developed deadfall traps (rocks propped up over a stringed stick, with bait set beneath, used to kill smaller animals.)

All of these deadly traps scattered around the landscape, while effective to fill the gravedigger's stomachs, had another effect they could not have foreseen - a very strong selective pressure for any animals that manage to survive them to learn to avoid them, or even to sabotage them. By catching and eating all of the naive animals, they inadvertently were selecting for smarter prey that would be increasingly harder to catch.

An evolutionary arms race was set into motion. It would be perhaps the most rapid of any so far on the world of birds as well as the most pivotal. Gravediggers were forced to become increasingly creative and innovative in trapping animals, while their primary prey species became increasingly smart and better able to avoid being caught.

Enter the standing antlear.

The standing antlear was a very numerous, fairly typical antlear species found across the forest of southern Serinarcta. Its primary trait, distinguishing it from related species, was its tendency to rise and stand for prolonged periods on its singular back leg while feeding. This posture was made possible with a special locking tendon on its ankle that let it hold this position for several minutes at a time without tiring and so maximized its reach when browsing.

It was not this tendon that the standing antlear would become noteworthy for, however. Rather, the standing antlear would become the primary prey species of the gravediggers of the south Serinarctan forest refugia and so over many generations were among the animals most dramatically affected by the selective process to learn to avoid traps. Around 3 million years ago their populations plummeted due to overhunting; only a few thousand remained of a species once numbering several million. But then they began to adapt.

A few individuals survived being caught and freed themselves, becoming trap-shy. Living in herds, other individuals would have observed and followed suit. A collective wave of caution spread across the remaining population, and groups became much closer knit; more eyes would be present to search out hidden pitfalls or deadly snares. Experienced, physically stronger individuals - primarily the older males - led the groups and learned over time how not only to find traps but to disable them. The young learned these techniques, though some still got caught in the process; this only meant that the survivors which lived to breed were even more intelligent, however, and that the next generation would be even more difficult to trap. The gravediggers responded in turn - for every sabotaged trap, they set a better concealed one. The antlears learned to avoid it, and the gravedigger had to innovate further. They invented snares - first simple footholds that merely held their prey in place, which then required the gravedigger to kill it. These were effective but very quickly the prey learned to disable them off one another and escape, so the gravediggers developed raised snares mounted to bent branches that, when set, would lift their victims into the air and strangle them. Yet for every innovation the gravedigger devised, its prey met it and some learned to sabotage it.

Predator and prey, caught in a competition of life and death lasting millions of years, evolved into an extraordinary relationship with no parallel ever before: a sapient predator hunting a sapient prey.

above: a group of early antlear people, descended from the standing antlear, sabotage a gravedigger's pitfall trap somewhere in the South Serinarctan forest refugia, roughly 264 million years PE.

1 Million Years Ago

Pinpointing the exact time that the gravedigger and the standing antlear each became sapient is quite impossible given the slow, cumulative change evolution operates upon. The gravedigger definitely reached this milestone first; it was near the cusp by the time it began setting its first pitfall traps, yet their behavior at this time was still much less flexible. The gravedigger reaching this rare pinnacle was remarkable, but not without precedent; smart predators living in situations that require frequent behavioral adaptation to changing conditions are among the most likely animals to eventually make this jump. What is rare is one sapient unintentionally selecting for the evolution of the other. This is exactly what occurred over several million years of hunting pressure upon the standing antlear. In perhaps the complete opposite of its intent, the predator's hunting pressure accidentally brought into existence the hardest of all prey to catch - that which was as self-aware and capable of complex thought as itself.

This had occurred without any doubt by one million years ago. By this time, the standing antlear species had changed considerably in a series of events building off the selective pressures put forth by their gravedigger enemies. The antlears had become much more closely social, living in large communities of many individual family units, each led by a large male and several mates; before the gravedigger's hunting pressure, these males would have been intolerant of one another and fiercely territorial, but a need for increased sociality for protection now reduced their aggression significantly. Instead of physical conflict, males switched primarily to showy display, and evolved brighter markings and long manes of colorful hair, kept through both summer and winter, as a signal of their fitness that could be advertised without harming one another. The bottleneck event of two million years prior that preceded their rapid gain of cognitive ability later benefited them, as all of the novel mutations that appeared in response could then quickly spread through the entire small population, explaining their fast and dramatic changes of physical appearance and social behavior in only a short timespan.

In their pursuit of the antlear, the gravedigger also changed. Pushed to innovate when their old tactics no longer worked, the antlear put them under their own artificial selection. The gravediggers which could learn new tactics to catch food later in life were much more successful, resulting in the window of learning extending in the species well past adolescence until it was eventually retained through adulthood. The modern gravedigger is much more behaviorally flexible than its predecessor and can pick up new skills throughout life. Yet it is not any less aggressive, and so cultural transmission of these skills remains relatively limited.

By one million years ago, gravediggers were giving up on hunting the standing antlear entirely. It had simply become too difficult. By this time, the ancestors of the antlear people were well-established and spreading across southern Serinarcta's remnant temperate forests, and with their newfound brains came the realization they could fight back against their enemies with the same weapons that had for so long been set against them. As soon as the antlears began engineering their own traps and weapons against the gravedigger, it retreated toward easier food sources. And so the gravediggers primarily switched toward hunting much smaller prey species, as the tables turned on an ancient ecological relationship. The gravedigger and the antlear were no longer predator and prey; they were mortal enemies, each capable of killing the other and so destined to be locked in a million year long cold war.

Eventually the war would end. But it would not be in a way either party would have ever first anticipated.