Municipal Darwinism – an ecological perspective


Municipal Darwinism is a widely used term to describe the principles and processes behind the evolution of traction cities of the Traction Era, a period in the history of planet Earth, which lasted for approximately one thousand years. Although it is primarily developed as a philosophy to describe, and somehow justify the predatory nature of the biggest traction cities, it is also useful to understand the rise and decline of Tractionism. Meanwhile, it is also useful to understand how Tractionism affected the wildlife on the planet. However, it is still more of a philosophy, rather than a valid biological process.

Origin of the traction cities

In order to understand what caused the evolution of traction cities, we first need to take a look at the world at the beginning of the Traction era. It has been more than 10 000 years after the Sixty-minute War, an immediate nuclear conflict, followed by 10 to 15 years of Slow bombs (militarized asteroids) impact on the Earth’s surface, and several centuries of catastrophic earthquakes, tsunamis, and volcano eruptions, that shaped the world as we see it at the beginning of the Traction Era. Although much of the negative effects of the nuclear war should be a fading souvenir in the collective memory of humanity, apparently, the climate is far from favorable, making it extremely difficult to support large societies in limited territories.

Obviously, a mobile settlement is much less sensitive to environmental impact than a static one. Therefore, the first nomadic societies at the beginning of the Traction Era were driven by the need to avoid catastrophic events and to find new resources to support themselves. However, resources were scarce, and the nomadic societies started to compete for them.

At this point, the evolution of traction cities was already driven by the pure Darwinian principle of “survival of the fittest”. In other words, in order for a mobile city to outcompete its rivals in the resource race, and survive a direct collision, it must be either quicker, larger, or both. Once again, the progress of human civilization, starting from nearly zero (after most of the technological advance was lost during the Sixty-minutes War) and reaching the construction of complicated moving colossuses was largely driven by the striving to survive. The engines of the traction cities developed quickly from men/animal-powered, followed by steam engines, etc.

However, the isolation of human populations into moving settlements has several negative impacts. First, it means that infectious diseases could spread and be even more devastating than in ordinary settlements. A clear example is the city of Anchorage, where a deadly virus was acquired from incoming people and quickly decimated the population of the city. Second, a comparatively isolated traction city also means a lack of migration of human beings, meaning a lack of gene flow and a weakening of the population itself.

Following this logic we can assume, that most of the traction cities were heavily underpopulated and in constant need of “fresh blood”. Thus, humans became a valuable resource themselves, rather than rivals, and after one city consumed another one, the population was first quarantined but later assimilated into the population of the larger city. However, we can also assume, that some gruesome practices like trade with humans also existed to battle the diminishing genetic diversity.

The food chain of traction cities

Considering that the traction cities represent a vital technological ecosystem, consuming each other and competing for resources, we must also expect a certain degree of speciation, forming a food chain, or food pyramid. The basis of the pyramid was formed by numerous static settlements and farming or mining hamlets and towns. These formed the group of primary producers, responsible for the acquisition and accumulation of most of the resources. Most of the other traction cities are predatory and composed the several levels of consumers, with few urbivores, or alpha-predators like Arkangel on top of the food pyramid.

Besides typical producers and consumers, several traction settlements also developed into more specialized “life” forms – scavengers and parasites. The first class, the scavengers are generally small settlements, specializing in collecting and recycling remnants of other settlements, as well as the leftovers of large traction cities. Parasites, on the other hand, are a group of highly specialized settlements, such as the Lost Boys of Grimsby. They are often referred to as pirates, although their approach to extract resources unnoticed by the host cities makes them more similar to parasites. The vampire towns of Nuevo Maya are also a typical example of parasites, clinging to a bigger city and slowly draining resources from it.

As expected, depending on the specialization, different traction settlements developed different adaptive features to better serve their purposes. Typical predators are characterized by large hydraulic jaws, vampires towns are equipped with attachment devices, while mining hamlets, besides digging devices, would also possess camouflage and are lighter and faster, to avoid and escape predators more efficiently. Some predators also combine into hunting packs, much similar to wolves, in order to ambush and take down potential prey more efficiently.

However, such “technosystem” would largely depend on the lower levels of the food pyramid. A constantly moving settlement would require an enormous amount of energy, and the bigger the traction city, the larger the requirements will be.  If there are not enough producers, the higher-level consumers would soon struggle to find suitable prey, which actually happened. A famous citation by Tom Natsworthy: “In the better days, London wouldn’t have bothered with such small prey.”, reveals that six hundred years into the Traction Era Municipal Darwinism was already in decline. Soon, tractionism became obsolete, and most of the surviving traction cities returned to a static regime.

Ecology of traction cities

Municipal Darwinism is a philosophy to describe the technological ecosystem, but traction cities were, for a thousand years, a major anthropological factor, shaping the world around them. First of all, every traction settlement represented a partially isolated ecological niche, ensuring a constant supply of food, shelter, and heat. This means that thousands of different species of insects, rodents, bats, birds, etc. would adapt and co-exist with humans, and would probably differ from similar species in other traction cities.

Besides them, a traction city would be also followed by a large number of associated species, that would follow it in order to scavenge the discarded remnants but also to take advantage of the impacted environment. As a rough example, the moving city would disturb the ecosystem, killing or scaring away hundreds of small animals, which would represent a perfect meal for hunting packs or predatory birds. Some species, like sparhawks, would hunt outside of the traction city but would nest and reproduce on the city itself.

The movement of traction cities throughout the Hunting Grounds would largely shape the vegetation, which would consist of fast-growing grass species and a lack of trees or shrubs. A moving city would constantly plow the soil surface, contributing to the exchange of minerals and organic matter, and would also contribute to the spread of certain plant species by moving large amounts of seeds at large distances. At the same time, mountains would remain largely unaffected and would establish undisturbed forests.


  1. Phillip Reeve. The Mortal Engines Quartet, Scholastic, 2001-2006.
  2. Phillip Reeve. The Fever Crumb Series, Scholastic, 2009-2011.

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