Galactic Threat? An Evaluation of Porgs as Invasive Species


Porgs, a recently identified species of avian-like creature nesting on the rocky shores of Ahch-To, have become a cause for alarm in the galactic ecologist community. After seeing how porgs have taken over the landscape on Ahch-To, the speed at which they colonize visiting spacecraft, and public interest in porgs as pets (Bibbiani, 2017; Whalen, 2017), some have expressed deep concerns that an invasion of porgs may be the next galactic ecological catastrophe. Other scientists dismiss both these concerns, suggesting that the proliferation of predators on other planets will prevent porgs from spreading throughout the galaxy unchecked. This report will provide a critical examination of the relative risks both to and from porgs. Because data on porg behavior and the broader ecological systems of Ahch-To are just beginning to be collected, this report is somewhat speculative and will rely on knowledge of similar species and ecosystems throughout the galaxy to supplement empirical observations.

Are Porgs Invasive?


Although some species, such as the purrgil, have been observed to engage in hyperspacetravel in nature (Wolkoff & Zwyer, 2016), most species that are not natural vacuum breathers have been restricted to their home worlds. Those that have proliferated across multiple planets have generally done so by stowing away on interplanetary vessels, or by being intentionally introduced by species with interplanetary travel technology. While these practices have elevated the risk of species becoming invasive within a planetary system, the advent of hyperspace technology has greatly elevated these risks. Species now have the potential to travel to anywhere in the known galaxy, or even into wild space, if they are able to attach themselves to the right ship. Therefore it is critical that we evaluate all newly encountered species, such as porgs, for their risk to galactic ecosystems.

Breznican (2017) was the first to publish concerns about the potential for porgs to act as an invasive species, but Rabaiotti and Murphy (2018) were the first scientists to examine this problem. Their analysis focused primarily on the survival traits of porgs – their rapid reproductive rate, flexible diet, limited flight ability, and willingness to live in close contact with sentient beings – and concluded that there may be significant potential for porg colonization. However, with limited data on porg behavior, biology, and colonization vectors, their conclusions remain speculative.

A Process-Oriented Model of Invasive Species


In order to assess whether porgs present a risk as an invasive species, it is important to clearly define an invasive species. Colautti and MacIssac (2004) suggest that the term ‘invasive species’ has led to considerable confusion, particularly when contrasted with terms like ‘alien species’, ‘noxious species’, and ‘exotic species’. They argue that describing a species as ‘invasive’ is a misnomer; the success and impact of a non-indigenous species being introduced to a new ecosystem are products of the interaction between the species characteristics, its adaptive range, and the ecosystem where it is introduced. This is important, because it recognizes that species which may have great potential to be invasive or nuisance species in one environment may fail to thrive and cause minimal damage in another. In order to clarify this issue, Colautti and MacIssac (2004) present a five stage, process-oriented model. By applying this model we can develop a reasonable assessment of porgs’ potential to become a galactic hazard, and steps that can be taken to contain any identified risks.

Stage 0 – Nature


In the initial stage of the model, the species of interest is existing in its native habitat. When porgs were first identified on Ahch-To by traveler Luke Skywalker (Kennedy & Johnson, 2017), they were a Stage 0 species. A species can remain in Stage 0 indefinitely; they can only proceed to Stage I by encountering an uptake mechanism (a vehicle that can transport them to a new environment). Skywalker’s arrival failed to provide an uptake mechanism when he chose to swamp his X-Wing fighter in a nearby cove; however the arrival of Rey and Chewbacca in a YT-1300 light freighter does meet this requirement. Once porgs boarded the vessel, they progressed to Stage I.

Stage I – Transportation

Porg Falcon

During this stage, the species is being transported out of its normal environment. For porgs, this represents the time spent on the Millennium Falcon after it takes off from Ahch-To until it deposits all of the porgs onboard. During this stage, two sets of barriers exist that determine whether a species progresses to greater invasiveness.

First, the species must find a way to meet their basic physicochemical requirements (nutrition, atmosphere, thermal regulation, hydration, etc.) for the duration of transit. While some species, particularly invertebrates and bacterium, may accomplish this by entering a vegetative (“low power”) state, more complex creatures like porgs need to actively meet these needs. On the Falcon, life support systems provide porgs with acceptable air quality and heat; the latter is supplemented by the porgs’ insulating feathers and nests made from cushions and insulation within the Falcon. Food and water provide a more challenging task for porgs. Lacking the ample fish and waters of Ahch-To, it’s likely that the porgs exploited their adaptive range and either scavenged food stores intended for wookiee and human passengers, or directly solicited them from the freighter’s pilot. It is also possible that the porgs found edible components of the Falcon itself. It should be noted that the advent of hyperspace travel has dramatically reduced this barrier to species proliferation; instead of surviving in transit for days, weeks, or months, an intrepid porg may only have to survive a few hours before being deposited on a foreign world. If this is the case, then only the barest requirements for survival in transit apply!

The second barrier encountered at this stage is the release of the porgs from transit and into a new environment. This entails two sub-requirements; first the species must actually be released, and second it must survive the release process. In the initial documented report on porgs (Kennedy & Johnson, 2017), no release from transit was documented. However, three plausible mechanisms for release were observed. The first occurred when a vessel occupant, Rey, was jettisoned in an escape pod. This event had a low likelihood of successful release due to limited capacity and high probability of destruction. Had there been porgs onboard, they would be introduced into an environment not unlike the Falcon itself, and effectively remain in transit indefinitely. The second opportunity for release occurs as the Falcon engages in battle over the planet of Crait. Because the Falcon retained structural integrity, no release occurred; had the Falcon lost structural integrity, then porg release would have occurred. However, this release would be unlikely to be successful, as porgs released in such a manner would have a low probability of survival. The final and best opportunity for porg release occurred when the Falcon landed on Crait and opened its boarding ramp to new passengers. Porgs which exited the Falcon at that opportunity would be likely to survive and move to Stage II on Crait. This final mechanism for release remains a viable strategy so long as the Falcon continues to house porgs.

Stage II – Introduction

Porg Window

At each instance where porgs are successfully released from the Falcon, they will become a Stage II species. At this stage, the primary task for the species is survival. Species at Stage II must accomplish two tasks.

First, they must succeed at environmental survival. This means meeting their basic physiochemical needs for food, water, shelter, and atmosphere, just as it did while they were in transit. Unlike in Stage I, however, species must find sustainable sources for these needs. They must also navigate ‘community interactions’ with potential predators, competitors, and symbiotic species. Thus the survival of the species in the introduction phase depends greatly on the degree to which the environment is tailored to it, and the degree that it can adapt in the short term. For porgs on a planet like Crait, they are likely to struggle to find adequate sources of food and water (due to the planet being a massive salt desert). While they may be able to find sufficient shelter to retain warmth during the night, they will also likely experience significant predation by the native vulptices. The best chance for porgs to survive on Crait would be to form a symbiotic relationship with humans or other sentient species that could provide them with food, water, and protection from predators. With the evacuation of the resistance from Crait, it becomes almost impossible for porgs to survive there. The introduction of porgs to a more environmentally friendly or populous world, however, could be more successful. On a world like Naboo, they would be more likely to find the food, water, and shelter needed for survival (though they would still be very vulnerable to predators).

The second barrier at this stage is reproduction. Species with rapid reproductive cycles and who have minimal energy investments in their offspring tend to do best at overcoming this barrier. On Earth, species that exemplify this high-speed low-investment strategy can be found in invertebrates and bacteria who can produce new generations in a matter of hours or days and have no parental role. Examples of slower and more invested species are those that must wait extended periods to reach sexual maturity, have extended gestation or incubation periods, and must care for their young for long periods of time. Humans are a good example of one such species. Porgs are best characterized as having intermediate reproductive cycles and moderate investments in their offspring. They lay small to moderately sized nests (unfortunately we lack data on sexual maturity, incubation periods, frequency of egg-laying, or egg survival rates), and must protect and care for their young for an undetermined period of time before they are able to be independent. Assuming porgs can be introduced into an environment that meets their survival needs, the primary barriers to reproductive success will again be predators. While on Ahch-To the porgs have no known predators and exploit cliff side nests for protection, other planets might not afford these securities. Porgs’ best chance for success here again relies on support from a symbiotic species, such as humans raising porgs as pets or food.

Without an optimally exploitable environment with few predators feeding on porg-like creatures, it seems porgs are unlikely to be successfully introduced. Statistically, only 1 of every 10 species imported successfully completes introduction (Williamson & Fitter, 1996), so porgs will be in good company if they don’t succeed.

Stage III – Establishment

chewie and the porgs

If a reproductive colony of porgs is able to survive environmental hazards, then they will progress to Stage III. In this stage, a species is still localized and rare in its environment. To continue successful colonization it must spread geographically and numerically, and it must work towards becoming a dominant species in the environment (ecologically, this means representing the majority of biomass within their niche).

As a species continues to increase in population, its members will begin to distribute geographically in the new environment, and thus expand their range. The principal limiting factors for this are the continued availability of environments where physiochemical needs can be met and the community interactions are favorable for survival and reproduction. A species that is able to become widespread progresses to Stage IVa status, and is considered to be an invasive species in its ecosystem. Because many planets in the known galaxy are monoclimate worlds, the risk of established species becoming widespread is substantial and limited primarily by geological features (rivers, canyons, and mountains) or artificial barriers (cities, roadways, etc.) If porgs were able to successfully establish themselves on a planet like Naboo or Takodana, widespread distribution would be only a matter of time. Conversely, if porg establishment is dependent on a symbiotic relationship with a sentient species like humans (e.g., Coruscant), then the risk of widespread distribution is reduced.

Within the established territory, the species must also work to achieve dominance in its environment. This may be accomplished by being more efficient at reproduction and feeding than competing organisms, exploiting a wider variety of food sources, developing more effective defensive strategies, and preventing the reproductive success of other species. A species that accomplishes this task is considered a Stage IVb species; these are not considered invasive but rather as having a dominant colony. Porgs are unlikely to achieve this task unless very specific environmental factors are occurring (a lack of predators, a lack of competitors, or competitors with lower levels of reproductive fitness). Where these factors do occur (as on Ahch-To), they will most likely occur due to the relative isolation of the established territory.

Stage IV – Expansion

Stage IV is reached when a species either becomes geographically widespread, or becomes the dominant species in it’s environment. Progression from this stage requires meeting the criteria of being both widespread and dominant across that range. The principal tasks and barriers for accomplishing these remain the same as during Stage III, but species may now be able to leverage their successes from that stage to increase the probability of success. Species which have become widespread may be able to discover localized areas where they can achieve dominant status, and then work to erode barriers to dominance in other areas. Species which have dominance can work on incrementally expanding the geographic area they dominate until they are widespread. For porgs, the likelihood of achieving either status is low (as discussed above), but achievement of both would require their introduction in an environment uniquely tailored to their needs; outside of Ahch-To we have yet to identify such a planet.

Stage V – Widespread and Dominant

If a species is successfully introduced, becomes established, and achieves widespread dominance within the environment, then it has reached Stage V. At this point, we often see drastic changes in ecosystems – species being driven to extinction by competition or excessive predation, starvation due to over-grazing, erratic changes in vegetation and topography, etc. In developed areas, this is when economic and infrastructure damage are also likely to occur. As the ecosystem attempts to restore homeostasis, it may undergo irreversible changes and dramatic loss of species diversity. In the unlikely event that porgs achieved this stage, it seems most likely that the porgs would overtax their food supply, leading to a collapse in the baitfish population (and in turn, the porg population).


Based on the process model, it seems unlikely that porgs present a credible threat to the galactic ecosystem at large. Although they may feel personally invasive, they lack the adaptive range and reproductive vigor to successfully establish a colony on most planets without substantial human assistance. In those circumstances where porgs would be able to establish a foothold, achieving widespread and dominant species status remains unlikely. Of course, our study of porg biology and ecology is still very new, and we may discover in the future that porgs have greater adaptive range, defensive capabilities, and reproductive vigor than we currently observe. If such findings are obtained, a re-assessment of the invasive potential for porgs will need to be undertaken.

Of more concern perhaps is the risk that invasive species may arrive on Ahch-To and present an existential threat to the porgs. As we have seen through our analysis, porgs thrive in a relatively narrow ecological niche that relies on minimal competition and predation. The introduction of a more reproductively successful seabird, or that of a terrestrial or avian predator feeding on porgs or porg eggs could lead to rapid extinction among the porgs of Ahch-To. Similarly, the introduction of new aquatic predators or environmental hazards which destabilize baitfish populations could readily lead to famine and decimation of porg colonies. The Galactic Senate is strongly urged to consider establishing protected status for the Ahch-To system to avoid jeopardizing these unique and fascinating creatures.

Sad porg

Thanks to Heath for the invasive porg photoshops at the top of this post.

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