The Legacy of Heorot

The Legacy of Heorot is a science fiction novel written in 1987 by Larry Niven, Jerry Pournelle, and Steven Barnes.^[1] Reproduction and fertility expert Dr Jack Cohen acted as a consultant on the book, designing the novel life cycle of the alien antagonists, the grendels.^[2]

This is the first book in the Heorot series. It concerns the establishment of the first human colony on Avalon, fourth planet of Tau Ceti.

Plot summary

Plot setup

Two hundred colonists arrive on Avalon to found a new community, having made the 100-year journey from Earth in suspended animation on the starship Geographic (the expedition is funded by the National Geographic Society). The colonists, all selected for their outstanding physical and mental attributes, make a terrible discovery: though the suspended animation technology which permitted them to survive the journey worked well enough, it had unforeseeable side effects due to the unprecedented duration of its use. Their intelligence and reasoning skill are damaged. Some are only mildly afflicted, while others have intellectual disability; eight cannot be reanimated at all. The book opens with the colonists learning how to live without the sharp and nimble minds they all once had.

The colonists build a town on the island of Camelot and begin growing crops and stocking the nearby waters with terrestrial species of fish to complement the samlon, a local aquatic species. The island seems like a paradise, and the colonists quickly become overconfident in their security, much to the frustration of the expedition security officer (and only former soldier), Cadmann Weyland.

But then unsettling events begin to happen: missing animals, fences torn down, etc. The colonists' impaired minds prevent them from properly analysing what is going on, and in a panic Cadmann is blamed, accused of deliberate sabotage to further his agenda. When a baby and its mother are killed while Cadmann and his only supporter are away on a hunt for the creature he believes is the cause, the colonists become increasingly irrational. When he returns alone (his companion having been killed during the hunt), badly wounded, and with a chunk of burnt tissue he claims is from the monster, he is drugged and restrained. Then the creature attacks the camp in revenge.

Despite the colonists' advanced weapons and larger numbers, ten people are killed just in driving the creature away. This proves to all the colonists that there is a deadly and efficient predator native to the island.

Cadmann, however, is now completely unwilling to assist the community. He leaves the colony to set up a homestead on a bluff further up the mountain that forms the basis of the island, living apart from the community in despair. A woman visits him in the hopes of persuading him to return, but she stays with him and eventually conceives his child. As a result, he has an epiphany: the colonists may have brutalized and betrayed him, but their children are innocent, and deserve to be protected; he returns to assist the colony.

The colonists are confounded by the ecology of the island, as there does not seem to be a sufficient food source for the creatures to inhabit it. The colonists, using new weapons and Cadmann's tactics, are able to kill their first creature and Cadmann calls in with the message "Grendel is dead", referring to the creature in the poem Beowulf.

The autopsy reveals that grendels (as the creatures are now known) are crocodilian in appearance and behavior, with jaws that can crush steel. Their bones are significantly stronger than those of humans, as they are not based on calcium. They have a sense of smell better than a dog's. Studying its brain shows it is not fully sapient, but that it is not far off, and is at least as smart as a gorilla. Its claws are not just weapons, but exert enough traction for the creature to sprint up rocky cliffs. Though it is not a true amphibian – it cannot breathe water – it does possess an integral snorkel enabling it to move undetected beneath several feet of water. Its cardiovascular system and musculature give it strength and stamina far beyond that of humans, and that is without its primary evolutionary advantage: A super-oxygenated blood supplement.

A grendel can, on demand, release a chemical supercharger into its blood that does to it what nitrous oxide does to internal combustion engines – enable short bursts of speed in excess of 100 miles per hour. This trait makes the grendels devastating, but is also the key to their destruction. The supercharger, when used, generates large amounts of waste heat that warm up grendel bodies so rapidly they will die after using it if they do not immediately return to water to cool off. With this knowledge and their technology and tactics, the colonists are able to wipe out the grendel population within several months, making Cadmann a hero to the people who previously turned on him.

However, the colonists make a disturbing discovery: the grendels and the aquatic samlon are actually the same species. Their life cycle is similar to that of terrestrial frogs – the herbivorous samlon are in fact the juvenile form of the carnivorous grendels. Like certain species of frogs, they change gender over the course of their lifetimes. The juvenile samlon are male. The adult grendels are female. Interaction is unnecessary as the grendels continually lay their unfertilized eggs in the water for the samlon to fertilize. And like many species of frogs, they are cannibalistic – if no other prey is present, they will eat their own young.

At some point in the recent past, most of the prey animals on the island were destroyed by an unknown cataclysmic event. (It is left to the reader to draw conclusions as to what actually happened. Over-predation by the grendels is subtly suggested). Among the few surviving species on the island were the samlon, and thus the grendels. Cannibalism became the rule instead of the exception. Only the fastest juvenile samlon survived predation by grendel females to become adult grendels themselves, and this drove the species to evolve at an immensely accelerated rate. This resulted in the incredible predatory abilities of the grendels. When the colonists introduced terrestrial fish into the ecosystem, they provided the grendels with an additional food source, leading to a spike in adult grendel population, making it strong enough to initiate the attacks. The colonists have just exterminated the adult grendels. But as there is now no check at all on the samlon population, they all become grendels, meaning that instead of a few dozen grendels, there are now thousands.

Cadmann again asserts control. The grendels cannot hunt away from water, so the colony's pregnant women, children and essential specialists are evacuated to the Geographic. Combat is joined. At first, the colonists' technology and tactics serve them well. The laser-based welding tools and plasma-based drilling equipment are used as weapons. Whatever liquid hydrogen can be spared from the shuttles is used to fight the grendels as well. Cadmann observes mass grendel behavior and discovers that packs of grendels can be sent into a shark-like feeding frenzy by spraying them with blood taken from dead grendels, especially if it is laced with traces of the "supercharger" chemical extracted from the organ that secretes it, as this chemical triggers an immediate "fight" instinct. Tracer bullets are also used to ignite the supercharger gland in their bodies. The colonists ultimately discover and utilize a new tactic – they harvest supercharger from dead grendels and spray it over the grendel horde with crop dusting equipment, driving hundreds of them into a frenzy and killing many of those remaining.

But as the grendels' numbers fall, their individual strength rises as every dead grendel is food for the rest. Eventually, all that remain are the strongest and fastest full-grown grendels, and the colonists make a planned retreat to Cadmann's Bluff, Cadmann's carefully designed mountain hideaway which has been well-stocked and reinforced with defenses. As the horde approaches, they are sprayed with more supercharger, sending them into a frenzy once more. When they begin climbing the Bluff, Cadmann sets off an avalanche using a deadfall, killing even more. The grendels, though not as smart as humans, are smart enough to learn, given time and lots of experience. Their behavior changes as they realize the remaining colonists are not worth dying to reach when there are other grendels to kill. The colony is saved.

A year later, the grendels are being driven to extinction. Now that the grendel life cycle is known, the colonists continue the hunts, but this time the samlon are targeted as well. The new tactics, supercharger spraying and recorded grendel challenges, make them almost a routine chore. The terrestrial fish are gone, and will not be reintroduced, forcing the grendels to drive their own species into extinction. Soon the grendel threat will be eradicated. Now rebuilding can begin, and this time, the colonists will not be caught unaware. The battle against the grendels has killed many of the colony's men and left a surplus of women, and a new social organization based on bigamous marriages is taking shape. The mainland is being carefully explored, and the colonists have high hopes. Communications with Earth were cut off by the Grendel Wars. Now that it is over, the colonists hope the story of their battle will inspire Earth's population to restart the colonization program.

Themes

The story is largely concerned with the struggle for supremacy between humans and grendels, and more generally with the relationship between humans and our natural environment. The Avalon colonists inadvertently worsen their own predicament with their first attempts to rid the island of grendels, because they failed to fully understand the grendels' role in the local ecosystem. The book demonstrates that nature is a complex web of interdependent species, which human intervention can easily disrupt with unpredictable results. This is a theme also explored in Jurassic Park.

The book also draws from some of Robert A. Heinlein's work involving the adage "if you desire peace, prepare for war," in exploring the conflict between the civilian leadership of the colony who see no danger, and the military advisor who believes that danger always exists in the future. Cadmann is successively treated as crackpot, savior, scapegoat, and hero as the needs of the colony for his talents change.

Finally, the book explores the social dynamics of a situation where nobody can trust anybody else's judgement, not even their own. The eventual outcome of this is more fully detailed in the sequel, Beowulf's Children.

References