Tag Archives: ecology

Butterfree vs. Cutiefly: Pokémon Competition (and we ain’t talking about battle)


In nature, there are a limited amount of resources and life is in constant pursuit of these resources. It is this pursuit which drives many interactions from predation to parasitism. But, what is a resource?

A resource is anything that is consumed by an organism to grow and maintain its life functions. Food is always a resource, as is water for land-dwelling organisms. However, a resource doesn’t always have to be literally consumed. Space is a vital resource, particularly for sessile, or immobile, organisms. In this instance, space is “consumed” when an organism occupies it and subsequently relinquished upon that individual’s death. Potential habitats such as hollowed logs or abandoned burrows also constitute resources to be consumed.

A resource may be in demand by one species or many species, but regardless only a select number of individuals can consume a resource at a time. When a resource is consumed, its availability to other individuals decreases. This is the crux of competition.


Competition simply describes situations where an individual or group of individuals reduces the availability of a resource to other individuals through either consumption of the shared resource or by directly interfering with other individual’s ability to access the resource.

Organisms compete for a range of shared resources from food, to shelter, to space, and these competitors play by brutal rules—last man standing wins. A far cry from the fictional faints of the Pokémon world…or not.

Just as they compete in battle, Pokémon also compete in nature without the safeguard of trainer referees to steer these confrontations away from more fatal outcomes.

A prime example of this struggle can be found with an unsuspecting duo—Cutiefly and Butterfree. While the Bee Fly and Butterfly Pokémon respectively give the appearance of being nothing more than polite pollinators, the two are engaged in a fierce fight for flowers:

Nectar and pollen are its favorite fare. In fields of flowers, it gets into skirmishes with Butterfree over food. (Cutiefly, Pokémon Ultra Sun)

Nectar from pretty flowers is its favorite food. In fields of flowers, it has heated battles with Cutiefly for territory. (Butterfree, Pokémon Ultra Moon)

This is an excellent example of interspecific competition, when individuals of different species compete for resources. In this case, the resource being competed for is nectar.

Interspecific competition regulates competing populations, often suppressing both from reaching population levels they would otherwise achieve in the absence of competitors. Suppose, a Cutiefly reaches a flower before a Butterfree. The nectar inside is consumed and while nectar is a renewable resource with time, for the time being the availability of nectar for all Cutiefly and Butterfree decreases. But, it is the Cutiefly population which reaps the benefits as another individual can maintain its life processes, ensuring that is population remains up. The inverse is true for the Butterfree population, where another individual is deprived of nectar and thus must seek another nectar source or die, lowering the Butterfree population.


These interactions can lead to situations where one competitor proves better at consuming the shared resource drives the lesser competitor to extinction. This is the competitive exclusion principle.

Coined by Garrett Hardin (1960), the competitive exclusion principle says that if two species are competing for a limited resource, the stronger competitor will drive the weaker to extinction. As put concisely by Hardin, “Complete competitors cannot coexist.”

This principle is derived from the findings of G. F. Gause. He conducted experiments with two species of paramecium, a type of microscopic organism that could live in petri dishes. Grow separately, the paramecium grew rapidly, limited only by the food available to them in their respective dishes. However, when Gause grew them in the same dish with the same amount of food, one species proliferated while the other died out.


Later experiments with other organisms found similar results. Fruit flies, mice, beetles, and plants; in every case only one competitor emerged victorious while the other died out.

Why does this happen?

Simply put, if one organism can more efficiently consume a resource and decrease its availability to its competitor, then the dominant species increases, while the population of the lesser competitor decreases. The gap widens over time, and soon a negative feedback loop forms where the more abundant the dominant competitor becomes, the fewer resources there are available to the ever-dwindling numbers of the lesser competitor, further leading to its population’s decline.

This indirect interference with the competing population is referred to as exploitative competition. But not all competition is conducted indirectly. Sometimes, a species must take matters into its own hands (or fins, claws, leaves, etc.) to ensure they do not end up on the wrong end of the competitive exclusion principle. This is called interference competition, or when direct antagonistic actions are taken against a competitor to procure a resource, or at the very least prevent it from fall into the competitor’s hands (or fins, claws, leaves, etc.). And Cutiefly and Butterfree’s actions are antagonistic to say the least.

Butterfree’s entry in Pokémon Ultra Moon speaks of “heated battles with Cutiefly for territory” and Cutiefly’s Pokémon Ultra Sun entry states “it gets into skirmishes with Butterfree over food” in the flower fields of Alola.


So, if complete competitors cannot coexist, is it only a matter of time until either Butterfree or Cutiefly drive the other to extinction on Alola?

Well, maybe not.

On the offset, Cutiefly appears to be the dominant competitor. It’s Pokémon Sun Pokédex entry says that it can sense auras and thus “identify which flowers are about to bloom.” This alone gives Cutiefly a significant advantage over Butterfree. Being able to visit flowers immediately in bloom not only allows Cutiefly to fulfill its nectar needs before Butterfree but lets Cutiefly avoid direct confrontations with its competitor, who has a literal competitive advantage bearing poisonous scales on its wings which according to its Pokémon Moon entry scatters over Pokémon who attack it. With Poison being a weakness of Fairy-Type Pokémon such as Cutiefly, these encounters could prove fatal for the Bee Fly Pokémon.

Indeed, these Pokémon are “complete competitors,” but they can coexist.

A peaceful coexistence can be achieved through niche partioning, the ecological equivalent of dividing your childhood bedroom in half with your annoying sibling so you do not kill each other. Niche partioning occurs when competing species coexist by either using different resources or continuing to use the shared resource but occupying different habitats either physically or temporally (i.e. are active at different times of the day or during different seasons).

A textbook example of niche partioning comes from a study conducted by Joseph Connell (1961) on two species of barnacle, Balanus and Chthamalus.

The two barnacles lived in the intertidal zone of an ocean cliffside where the shared resource is space. Connell found Balanus barnacles the better competitor, as they had heavier shells to withstand Chthamalus crowding and grew rapidly, faster so than their competitor. Additionally, these feisty crustaceans would edge themselves under Chthamalus shells and pry them from their spots!

How could Chthamalus barnacles persist under such competition? Well, for all their shell-shoving, Balanus were not too keen to dry land, unfortunate for a creature living in the intertidal zone. Thus, they were confined to the lower portions of the cliffside where water had a more constant presence.


However, Chthamalus were desiccation-resistant, and could survive low-tide conditions. So, they colonized the upper portions of the intertidal zone free of competition.

Chthamalus surely could have lived in the lower intertidal zone as well, its fundamental niche consisted of both areas. But competition from Balanus limited it to the upper zones, its realized niche.

Thus, they were able to coexist, in segregation perhaps, but at least no one is shoving anyone off a cliffside.

A similar peace can be achieved between Cutiefly and Butterfree as well.

Like Balanus, Cutiefly may be the dominant competitor with its aura-sensing abilities, but the Pokédex gives no indication that it would be able to gather nectar under rainy conditions. However, Butterfree’s does:

Water-repellent powder on its wings enables it to collect honey, even in the heaviest of rains. (Pokémon Silver Version)

Butterfree could easily harvest nectar during periods of rain in which it wouldn’t have to compete with Cutiefly, or better yet find a realized niche in areas of Alola more prone to rain such as Route 17 or Po Town where Cutiefly couldn’t achieve flight.

Competition is a fact of life, but it does not always have to end in extinction.

Accurate Pokédex Entries

Cutiefly, the Bee Fly Pokémon: Using its aura-sensing abilities, Cutiefly can identify which flowers are about to bloom, allowing them to gather nectar before Butterfree arrive to pester them. The two are engaged in interference competition over nectar.

Butterfree, the Butterfly Pokémon: To avoid competition with Cutiefly, Butterfree tend to cluster in areas where rain is common as their waterproof scales allow them to gather nectar in the heaviest storms. This niche partioning allows them to co-exist peacefully with Cutiefly.

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Works Cited and Further Readings

Connell, Joseph H. 1961. The influence of interspecific competition and other factors on the distribution of the barnacle Chthamalus Stellatus. Ecology 42:710-723.

Hardin, Garrett. 1960. The Competitive Exclusion Principle. Science 131:1292-1297.

Ricklefs, Robert E. 2008. The Economy of Nature. 6th Edition. W.H. Freeman and Company. New York, NY. pp. 328-345.

Pokémon Eating Pokémon: Do Pokémon Eat Each Other? (Introduction)

Pokemon eating pokemon

“We are not afraid of predators, we’re transfixed by them, prone to weave stories and fables and chatter endlessly about them, because fascination creates preparedness, and preparedness, survival.” – E. O. Wilson

One of the most fundamental relationships in nature is that between predator and prey, otherwise known as predation. In simple terms, predation involves the consumption of one organism (prey) by another (predator). The interactions between predator and prey have fueled an evolutionary arms race, as predation is one of natural selection’s favorite tools for shaping life. The struggle for life has forged the vast biodiversity we see today—from the pyrotechnics of the bombardier beetles, to the assemblage of potent toxins of the Portuguese Man-O-War, to the breakneck dives of the Peregrine Falcon, life continues to push the limits of possibility to fulfill its ultimate biological purpose—to adapt, scatter, and survive.

The mandate of life to propagate itself has led to what many critics of evolutionary theory would consider a dark and grim world, a world governed by the Darwinian aphorism “Survival of the fittest”, a world where this concept is applied in all aspects of life, natural and social. It is with this portrait of the natural world that they postulate a greater purpose, and from that greater purpose they claim it is only reasonable to expect a greater hand guiding these dynamic interactions.

However, to view the dance between predator and prey as an unfortunate side effect of early man’s follies is to ignore the beauty that has arisen from this eternal struggle. For if the day does come when the wolf shall live with the lamb, it will surely herald the demise of life forever. A stagnant ecosystem is a dead ecosystem. The day where packs of wolves no longer chase down lambs will be a sign onto which this grand hand has dealt the final blow to his creation.

Just as the occasional conflagration is needed to clear the overgrown forest, predation and its, at times, heart wrenching cruelty, is necessary for the continuation of life.

As with many aspects of the natural world, this necessity extends onto the fictional universe of Pokémon. As discussed in previous entries, the Pokémon World is no stranger to interspecies interactions. Parasitism is alive and well in Parasect, a Pokémon who upon evolution has its mind and bodily autonomy hijacked by a parasitic mushroom on its back, an obvious illusion to the real-life Corydceps, a genus of fungi most notably featured in the Naughty Dog’s hit game The Last of Us. In Slowbro and Shellder—Mutualism, Commensalism, or Parasitism, I argued that Slowbro benefited from a mutualistic symbiotic relationship with Shellder. Perhaps the most obvious interaction between Pokémon is the trainer-mediated engagement in nonconsequential battle—otherwise known as Pokémon Battles. However, these interactions, for the most part, do not influence the greater ecosystem. Furthermore, all parties involved leave without substantial harm but without significant gain either.

Quite simply, Pokémon battles are ecologically meaningless encounters.

However, when Pokémon engage with each other outside of the mediation of a human-trainer referee, these encounters become far more interesting. The hands of evolution take shape and suddenly trivial encounters hold life and death in the balance, the tools of battle are wielded without restrain as Pokémon fights Pokémon with the intent of either walking away with their life intact or feasting on the corpse of their fallen opponent.

To answer the question posed by the title; yes, Pokémon do eat other Pokémon, though explicit details of these interactions are scarce at best or left in vague ambiguity. For the purposes of this survey, with two notable exceptions, only entries which explicitly cite Poké Predation will be considered a true predator-prey relationship. Indeed, the Pokédex is rife with mentions of Pokémon chasing and consuming an unidentified “prey”, but since the question of whether animals exist in addition to Pokémon in this fictional world is yet unanswered definitively, for the sake of simplicity we will limit our inquiry to those we are sure prey on their fellow Pokémon. But make no mistake, even with this criterion, the Pokédex is abundant yet with tales of fierce predation, many of which have appeared already on numerous creepy Pokédex entries lists. However, this survey of Poké Predators will illuminate new entries and Pokémon precisely skimmed over and deepen our understanding and appreciation for the complexity of this world and our own.

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Is Magikarp an Invasive Species?

I Love Magikarp

Totally pathetic, unreliable.

These are the first words used to describe the lowly Fish Pokémon in The Magikarp Song. And while the song is ultimately an ironic ode to the oft-mocked Pokémon peppered with tongue-in-cheek jabs at the fish, one only need take a cursory glance at Magikarp’s Pokédex history to gain a sense that the scientific community—or whoever authors these fantastical entries—does not particularly hold Magikarp in the highest esteem:

In the distant past, it was somewhat stronger than the horribly weak descendants that exist today. (Pokémon Red and Blue Versions)

An underpowered, pathetic Pokémon. It may jump high on rare occasions, but never more than seven feet. (Pokémon Gold Version)

This weak and pathetic Pokémon gets easily pushed along rivers when there are strong currents. (Pokémon Crystal Version)

Magikarp is a pathetic excuse for a Pokémon that is only capable of flopping and splashing. This behavior prompted scientists to undertake research into it. (Pokémon Ruby Version)

It is virtually worthless in terms of both power and speed. It is the most weak and pathetic Pokémon in the world. (Pokémon FireRed Version)

It is said to be the world’s weakest Pokémon. No one knows why it has managed to survive. (Pokémon Diamond Version)

Many of the lighthearted lyrics of The Magikarp Song are lifted directly from the Pokédex, but only when read alone without the catchy tune playing in the background can one truly taste the venom seeping from the belittling and, honestly, slanderous text.

The main ethos of this blog is that just as there is something to be learned from every organism, so too there is also something to be learned from every Pokémon. And The Pokémon Games seem to have a similar message at their core—that all Pokémon, big or small, strong or weak, have something to offer. The immortalized words of Elite Four Karen speak to this truth:

Strong Pokémon. Weak Pokémon. That is only the selfish perception of people. Truly skilled trainers should try to win with their favorites. (Pokémon Silver, 2000)

Yet, the mockery of Magikarp throughout the Pokédex seems to contradict this central core message.

It was my original intent for this Pokémon Day, to write in defense of Magikarp. To extol its high fecundity and amazing osmoregulation, to applaud its persistence throughout the ages despite being “weak” and to explore the life history traits of Magikarp and the evolutionary trade-off that might have led to its current “weak” form—topics that I may cover in the future.

But, during my research, I came across several troubling traits in Magikarp that lead to a worrisome conclusion that might explain why the Pokédex displays such distain for the Fish Pokémon. Magikarp is an invasive species.

We’ve discussed invasive species previously regarding the Alolan forms of Rattata and Meowth (Alolan Rattata and The Feral Cat Problem), and it is now consensus opinion within the community that invasion is a key theme of the Generation VII games. Additionally, it could be argued that most, if not all Pokémon are invasive, or nonindigenous at the very least. However, I propose that Magikarp is not only invasive, but is having detrimental impacts on ecosystems all across the Pokémon World.


Is an Invasive by Any Other Name Just as Sweet?

You may have noticed I’ve been careful not to use invasive and nonindigenous interchangeably. Anyone whose been introduced to the topic before may be accustomed to one or both or any of the tens of terms used to describe nonindigenous species—alien, introduced, exotic, imported, naturalized, transient—the list continues for as long as there are papers written on the subject. This abundance of terms can lead and has led to much confusion about what exactly is being described. Is the discussion limited to only harmful organisms? Are benign organisms invasive? What counts as alien? Are humans the only vector by which these organisms can be introduced?

Even the most frequently used term “invasive” has found itself carrying differing definitions throughout the scientific literature where it has been used as:

  • A synonym for nonindigenous
  • An adjective for nonindigenous species that have invaded natural areas
  • A term used to distinguish between nonindigenous species established in cultivated habitats (i.e. domesticated farm animals) and those established in natural ones (i.e. “the wild”)
  • A term used to describe widespread nonindigenous species
  • A term used to describe widespread and harmful nonindigenous species

If multiple, differing definitions can be derived from a single term, the compounding effect of having tens of terms in use can lead to even more confusion for scientists and especially the public. Additionally, even if we limit ourselves to “invasive” problems can arise when discussing nonindigenous species as generalizations could easily lump together organisms that do not have comparable effects on their habitat.

Here’s an example. The common goldfish is considered invasive under two of the above definition as it is (1) nonindigenous to the United States, and (2) widespread through its invaded habitat since its introduced into American waterways thanks to neglectful fish owners. However, goldfish rarely achieve high enough densities to cause significant harm to their habitats. Contrast this with the zebra mussel, a textbook invasive species from Eurasia which has cleared waterways and clogged pipes throughout North America. The zebra mussel is both widespread and found at high enough densities to have adverse effects on its habitat. Both organisms are considered invasive, yet in a generalized discussion of invasive species they do not appear to be exhibiting the same phenomenon.


Naturalized goldfish (left). Zebra mussel infestation (right).

Furthermore, use of invasive terminology can lead to misleading conclusions about the organisms themselves. As Colautti and MacIsaac (2014), authors of the paper from which this article draws heavily from, point out, the use of this language reinforces the mistaken idea that invasive species are some type of taxonomic group, that their invasive qualities are intrinsic to their being, forgetting that all nonnative species are native somewhere.

“Indeed the very terms used to describe NIS are misnomers in that nonindigenous species are actually nonindigenous populations of species. In other words, the same ‘species’ that are nonindigenous, naturalized, or invasive in one area are native somewhere else.” (Colautti and MacIsaac 2014)

Thus, Colautti and MacIsaac devised a framework to better classify nonindigenous species using a more neutral terminology. This the framework from which I will work within for the duration of this article.

Colautti and MacIsaac conceptualize nonindigenous species, referred to as “propagules” (a piece of a plant that can be snipped and planted elsewhere to form a new plant), as advancing through five stages.

First is Stage 0—the potential propagules still reside in their native “donor” habitat. The propagules enter Stage I when they are first “snipped” from their native habitat and transported elsewhere. If the propagules survive transport and release into their new environment they enter Stage II. Once introduced, propagules may achieve Stage III where they are “numerically rare” but have the potential to further establish themselves. From here, propagules can enter two diverge paths into Stage IV—become widespread (Stage IVa) or become dominant (Stage IVb). Once an organism has become both widespread and dominant, they have entered Stage V—what most people and conservation organizations would consider “invasive”.


From Colautti and MacIsaac (2014)

This new framework allows for distinction between nonindigenous species of varying ecological influence. Let’s return to our previous example. Under this framework, the goldfish would be classified as Stage IVa (widespread), while the zebra mussel would be Stage V (widespread and dominant).

So where does Magikarp fit into this framework?


Magikarp—the Invasive Pokémon

There are currently no hard-and-solid predictors of whether any given species will become invasive if introduced into a novel environment, but there are a few general traits that most successful invaders tend to have. Firstly, successful invaders typically mature early and reproduce rapidly. In essence, they adopt the reproductive strategy of freaking a lot, freaking early (censored for your children’s viewing). Additionally, good invasive species have high dispersal rates—are good at getting their offspring out into the further reaches of their habitat to become widespread and check off one box towards becoming a Stage V species.

Another good trait to have is being able to adapt to a wide range of environmental conditions. They are often tolerant of adverse conditions that other organisms would typically not thrive in, such as anoxic (low oxygen) or heavily polluted habitats. This adaptability can be achieved sometimes through phenotypic plasticity, when outward expression of certain traits changes depending on the environment (we talked more about this in Eeveelution Epigenetics). Successful invaders are also usually generalist, being able to consume a wide range of food sources and adapt to whatever happens to be lying around in their environment.

Lastly, most invasive species have an association with one species in particular—homo sapiens.

Humans introduce a lot of nonindigenous species to foreign environments. A review of nonindigenous species in the United States estimates 50,000 nonindigenous species in the US costing $137 billion annually in damages and loss of recreational value (Pimentel et al. 2000). Most are benign and are intentionally brought over, such as domesticated farm animals like dairy cows and chickens. Many are imported as pets, like the Burmese python which now infamously ravages the Florida Everglades. Others hitch a ride unintentionally, such as the zebra mussel which stowed away in the ballasts of cargo ships. As a rule of thumb, only 10% of introduced organisms will become invasive—only 4,500 of the 50,000-nonindigenous species in the US are considered invasive. This may explain why in regions abundant with nonindigenous Pokémon, only a few become invasive like Magikarp.

And Magikarp does appear to possess quite a few invasive qualities.

For starters, Magikarp seems to have fully adopted the freak-a-lot-freaking-early lifestyle. In game, Magikarp and Gyarados require the fewest egg cycles to hatch—indicative of a fast and early maturity. Additionally, the Pokédex entry for Pokémon Sun suggests Magikarp is also a rapid reproducer:

Although weak and helpless, this Pokémon is incredibly fertile. They exist in such  multitudes, you’ll soon grow tired of seeing them. (Pokémon Sun)

Pokémon Ultra Moon states that Magikarp can be found in “waters all over the world!” and this mostly rings true as Magikarp is present in every regional Pokédex except for Unova—possibly due to stricter regulations on introducing nonindigenous species since it is a US-based region. All of this would suggest high dispersal capabilities in reproducing Magikarp.

Furthermore, Magikarp displays a high tolerance across a wide range of environmental conditions. From the cold lakes of Sinnoh, to the polluted waters of Celadon City in Kanto, and the sunny shores of Alola, Magikarp thrives. Its entry from Ultra Moon speaks to this:

Thanks to their strong hold on life, dirty water doesn’t bother them at all. They live in waters all over the world! (Pokémon Ultra Moon)

Magikarp even exhibits some form of phenotypic plasticity in its ability to switch from fresh to saltwater, as Pokémon Yellow states, “It can be found swimming in seas, lakes, rivers, and shallow puddles.”

Most importantly, Magikarp has a close association with humans in the Pokémon World. In Kanto, and even strictly regulated Unova, Magikarp are sold as pets, similar to goldfish, a species of Asian carp which serves as the inspiration for Magikarp. In fact, this is a likely scenario for its introduction through the waters of the world. Tourists bought these Pokémon as pets while on vacation in Kanto and release them upon their return to their native region, as is the case with many exotic pets. Another possibility is that Magikarp was exported from its assumed native habitat of Kanto for the purposes of aquaculture else, just as several species of Asian carp were introduced into the US and Europe as foodfishes.

So where does this leave Magikarp under the framework established earlier by Colautti and MacIsaac? Well, by the evidence presented thus far, Magikarp is at least in Stage IV. Specifically, we know Magikarp is widespread (IVa). But is it dominant?

Dominance, in ecology, refers to how much biomass an organism constitutes in comparison to its competitors. In simplest terms, dominance depends on who is most numerous.

We obviously lack population data on Pokémon, so we’ll have to make do with what information we do possess—where each Pokémon can be found. I’ve taken all the fish Pokémon of each region where Magikarp can be found and compared the percent of the total region’s locations (routes, cities/towns, landmarks) that each Pokémon could be found in. And the results are not hopeful.

In Kanto, the presumed home range of Magikarp, there are only five “fish” Pokémon—Magikarp, Goldeen, Seaking, Horsea, and Seadra (yes, seahorses are fish). Of these five, two display dominance—Goldeen who can be found in 45% of locations, and Magikarp who covers 50% of Kanto. This shared dominance is to be expected in its native habitat, and further supports Kanto as being its native region


But in foreign regions, Magikarp truly makes a Splash.

In Hoenn, Magikarp competes with thirteen other fishes yet is present in 43% of locations. The closest competitor is Sharpedo at 15%, almost three times less than that of Magikarp. This trend holds for Sinnoh too, with Magikarp in 46% of locations. Native fishes like Finneon and Lumineon only have 10% coverage each. Kalos is a bit of an outlier, as it’s the only region with a pretty even distribution of fishes. There is no dominant fish and the fish with the greatest coverage is Luvdisc at 10%, greater than Magikarp in this region. This may be due in part to the massive richness found in Kalos—home to 24 different fish Pokémon, the most of any region. The greater competitions could perhaps damper the effects of Magikarp encroachment onto foreign territory.


However, in Alola, Magikarp is dominant once again with 30% coverage across these tony islands, outcompeting even Wishiwashi (17%). Furthermore, when compared with another widespread nonindigenous species who happens to be found all the same regions—Goldeen—Magikarp was found to have significantly greater coverage still.


So it does appear that Magikarp is at Stage V in at least three separate regions of the Pokémon World. But what impacts could Magikarp have on its invaded habitats.


Malicious Magikarp

Nonindigenous fishes in the US cost an estimated $1 billion annually in damages and losses. Introduced carp in particular have become a notable nuisance in American waterways. Asian carp have been known to leap up to 10 feet from the water when water motorists disturb their schools. In 2015, one man had his nose fractured and brow bones shattered by a leaping carp while inner tubbing on the Mississippi River.

An underpowered and pathetic Pokémon indeed.

Moreover, invasive carps can have devastating impacts on ecosystems. Asian carp decrease the amount of suspended vegetation in waterways and often deplete communities of benthic macroinvertebrates (Matsuzaki et al. 2009), organisms vital in the leaf breakdown process and export of organic materials and nutrients to downstream systems. Additionally, carp increases ammonium concentrations which can lead to algal blooms and subsequent anoxic conditions. Even in small numbers carp can be responsible for the deterioration of entire ecosystems. Bayer et al. (2009) found that when even carp biomass was 3-4 times lower than what is typically found in invaded systems, these fishes can reduce vegetation cover by 50%, halving waterfowl abundance in the process—all within the span of 7 years.

Further increases in carp left only 17% of the original surface vegetation and reduced waterfowl abundances to a slim 10% of original numbers.

If Magikarp is wreaking havoc anywhere near the scale of real-life carp, then the animus which Pokédex authors feel toward the Fish Pokémon is understandable—but ultimately misguided.

It is important in these discussions about invasive species to remember not to conflate the invasion of the species and the damage it does with the species itself. There are no “bad” animals just like there are no “bad” Pokémon, only bad humans who allow them to do bad things.

There is nothing intrinsically wrong with these organisms, they are just really good at doing what they do. Zebra mussels are really good at filtering water. Carp are really good at consuming vegetation. These traits would otherwise serve them well in the appropriate environment, and they serve really well in novel ones. It just happens that in these novel environments, their superb niche fulfillment happens to be detrimental to all other biota within the vicinity.

We must separate the damage from the organism and take a look in the mirror because you could say we are the most destructive invasive species—having conquered every continent and left our footprint on almost every habitat.

83% of terrestrial land is affected by human activity, and we’ve put to use 98% of Earth’s farmable land (Sanderson et al. 2002). Where oceans and mountains blocked the spread of potential invaders, humans provided a ferry, a bridge to novel worlds and novel niches. We were their vector into worlds unknown. And we are still reaping what we have sown.

So spare Magikarp your hate.

Because you’re totally pathetic, unreliable.

Happy Pokémon Day.


Accurate Pokédex Entry: A popular Kanto pet, Magikarp has since been introduced to waters all over the world! However, its rapid reproduction and high tolerance for polluted waters has allowed it to spread into almost every aquatic habitat and has become the dominant fish Pokémon in many regions, outcompeting even native species.

Click the Go Pokémon! button to subscribe and stay up to date on all the latest news in Pokémon Biology, and be sure to follow us on Twitter @PokeBiology and while you’re at it follow the author @JaredIsAWriter.


Works Cited

Bajer, P., G. Sullivan, and P. Sorensen. 2009. Effects of a rapidly increasing population of common carp on vegetative cover and waterfowl in a recently restored Midwestern shallow lake. Hydrobiologia 632:235-245.

Colautti, R. I. and H. J. MacIsaac. 2014. A neutral terminology to define ‘invasive’ species. Diversity and Distributions 10:135-141.

Matsuzaki, S., N. Usio, N. Takamura, and I. Washitani. 2009. Contrasting impacts of invasive engineers on freshwater ecosystems: an experiment and meta-analysis. Oecologia 158:673-686.

Pimentel, D., L. Lach, R. Zuniga, and D. Morrison. 2000. Environmental and Economic Costs of Nonindigenous Species in the United States. BioScience 50:53-65.

Schankman, Paul. 31 Aug 2015. Pleasant Hill man injured by flying Asian carp. Fox 2 now St. Louis. http://fox2now.com/2015/08/31/pleasant-hill-man-injured-by-flying-asian-carp/. Accessed 20 Feb 2018.



Alola Form Exeggutor: Island Gigantism at its finest (Pokémon Sun and Moon)

I have a soft spot for Exeggutor. Despite being an unsettling freak of nature, Exeggutor in all its three-headed glory has managed to creep its way into my personal pantheon of favorite Pokémon. One of my first posts on The Biology of Pokémon focused specifically on Exeggutor, and surprisingly there is a lot to unpack just from a biological perspective. My analytical mind has always been perplexed by the anomalous existence of this strange creature. While others mocked and scoffed at its design, I always felt that there was more to the story of Exeggutor, that it wasn’t just another freak Pokémon, that there was a meaning to the madness.

Earlier this week, the Pokémon Company dropped a literally game changing trailer, revealing several new additions including new Pokémon, Z-moves, the apparent departure from the traditional 8-gym system, Totem Pokémon, and of course, Alola Forms.

And guess who was the first Pokémon to get an Alola Form.

Within minutes, the Internet was abuzz with memes mocking Exeggutor’s Alola Form. While I find a few of the memes worthy of a laugh, I can’t help but feel pity for my dear Exeggutor, finally having gotten its long overdue day in the sun, only to be mocked by a merciless fan base.


But fear not Exeggutor, I will defend your honor.

For starters, Exeggutor having different forms depending on its environment is not a new concept. As early as Pokémon Crystal, the PokéDex mentions how Exeggutor will often grow many heads if it is living in a good environment.

  • Living in a good environment makes it grow lots of heads. A head that drops off becomes an Exeggcute.

The PokéDex entries from the Third Generation build on this, directly citing exposure to sunlight as conducive to head growth in Exeggutor.

  • Exeggutor originally came from the tropics. Its heads steadily grow larger from exposure to strong sunlight. It is said that when the heads fall off, they group together to form Exeggcute.
  • Originally from the tropics, Exeggutor’s heads grow larger from exposure to strong sunlight. It is said that when the heads fall, they group to form an Exeggcute.

The Alolan Islands provide the perfect environment for Exeggutor to thrive in, the tropical climate allows for year-round sunlight to fuel Exeggutor’s photosynthesis. Uninhibited by the winters that likely stunt its growth in more temperate regions, in the tropics of Alola, Exeggutor is able to achieve what the Alolan people refer to as its “true form”.


In biology, there is a phenomenon called island gigantism, in which animals grow to larger lengths than their mainland counterparts once they are isolated on an island. This is often coupled with another island phenomenon called island dwarfism which is the exact opposite, the island animals become smaller than their mainland counterparts.

Island gigantism usually takes place in smaller animals, often herbivores. When a population of organisms colonize an island, the ecosystem is usually still developing and has many niches unfilled. Additionally, most of these new ecosystems lack the huge predators that many organisms faced on the mainland, as the physical distant and separation by water often make it difficult for such animals to colonize islands. Without the selective pressure of predators, in addition to a wealth of resources and abundance of ecological niches to be filled, many organisms will thrive in these environments and evolve larger bodies since they are no longer inhibited by the selective pressures of their former ecosystem.


A great example of island gigantism is the Giant Tortoise, found in the Galapagos Islands. These massive creatures have no natural predators and can live upwards of one hundred years, with the longest recorded in captivity having lived to be 170 years old. They can weight up to 880 lbs. (400 kg to the rest of the world) and reach lengths of more than 6 ft. (1.87 m).  It is thought that they had evolved larger bodies in order to go longer periods without food and travel distances to obtain it.

Exeggutor is a classic case of island gigantism. Fewer predators reside on the Alola islands, and with an excess of sunlight, Exeggutor is free to push the limits of its evolution.

In fact, if you look at Alolan Exeggutor from an evolutionary perspective, its design starts to make more sense. Take, for example, its outrageously long neck. While at first it may seem out of place, if not, a major weakness, it also serves a very important purpose—photosynthesis. Exeggutor, being a plant, requires sunlight in order to complete the redox reactions that produce its food, glucose. With a longer neck, Exeggutor is able to reach above the treetops of the canopy and capture all the sunlight it needs. Additionally, Exeggutor has few, if any predators, while on these islands, so the selective pressures that would normally act against such a trait are not present, and thus, Exeggutor can evolve its neck to as far as its physical limitations allow it.


Another interesting aspect of Alolan Exeggutor is its tail, which is said to contain a fourth head that independently controls the tail. This is important because its three main heads are too high to reach the lower sections of its bodies, so in battle, the tail head can defend its base when the top heads are unable to. Another perk of having a fourth head close to the ground is that it can also keep an eye out for potential dangers while the top half of Exeggutor is busy basking above the treetops.

As absurd as Exeggutor’s Alola Form may appear at first glance, it is perfectly evolved for the Alolan ecosystem and serves as yet another example of how well the Pokémon World can reflect our own at times. So the next time you see a derogatory comment or a meme mocking the Coconut Pokémon, remember how amazing this freak of nature truly is.


For more on Exeggutor, check out the original post, Exeggutor: A True Freak of Nature.

Slowbro and Shellder – Mutualism, Commensalism, or Parasitism (Symbiotic Relationships)

One day you’re walking along a beach  and you stumble across a docile Slowpoke fishing with its tail, a common method of hunting as it allows slowpoke to sit around lazily will its food comes to it. The sweet juices found in its tail is a tasty treat to other Pokémon (as well as humans according to the events of Generation II). Suddenly the Slowpoke flinches, you watch as it hauls its tail to find not a fish but a bivalve locked into its flesh – a Shellder. The Slowpoke gives you a blank look of surprise before its body disappears in a glow and before your eyes it evolves into Slowbro, who now stands upright and appears more aware than before. The Shellder too has also undergone physiological transformation, its color has changed to a dull grey and its shell resembles that of a mollusk more than a bivalve, outfitted with spikes for added protection.

You, the astute Pokébiologist, recall that many Pokémon group together in order to evolve – Magnemite form groups of three in order to become a Magneton, two Beldum fuse together to form a Metang, and two Metang combine to form a Metagross. But those instances only involved Pokémon of the same species, here we have one Pokémon interacting with a completely different Pokémon to trigger a dramatic transformation for both creatures. Moreover, each Pokémon retains its own consciousness as far as you can tell, they remain separate entities that are merely working in unison. The geneticist side of you suspects the work of epigenetics (see Eevee Epigenetics), but you are an ecologist at heart and recognize immediately the symbiotic relationship between the two organisms.

In nature, organisms will often interact with each other, as it is difficult to avoid contact with other living things even if you tried. Something as seemingly innocuous as stepping on a blade of grass is a interacting with another organism. We often classify these various interactions by how the organisms involved are affected. Predation, for example, involves the consumption of one organism by another organism, providing nourishment to one while ending the life of the other. However, not all interactions are as grim. In some circumstances, organisms will interact to the benefit of one or more parties, usually. This close and long-term relationship between two organisms is referred to as symbiosis, and can come in three forms, in which the organisms in questions either work harmoniously together (mutualism), harmlessly mooch off the other (commensalism), or completely exploit one to its detriment (parasitism).

In regards to Slowbro and Shellder, defining their relationship is a matter of determining which parties benefit, and which are harmed. This may seem a simple task but when dealing with the world of Pokémon things can become complicated quickly. In our own world, nature has a bad habit of not falling into the cookie-cutter labels we create in order to organize its chaos, and that is perhaps even more true for the Pokémon World.


An Honorable Mention: Amensalism


No organism is an island, even an act as simple as walking across a field counts as an interspecies interaction.

Amensalistic relationships are present throughout the natural world, and it is perhaps because of its prevalence that it is often left out of most textbook discussions on symbiosis. Amensalism can be defined as a relationship in which one party is unaffected while the other is harmed and somethings straight up obliterated. In truth, its classification is merely a technicality of the relatively broad definition used for symbiosis, which at one point was strictly limited to mutualistic relationships. Essentially, every organism is involved in an amensalistic relationship, and thereby kind of negates any purpose in highlighting it as its own relationship. Refer back to my previous example of you stepping on a blade of grass. That is an amensalistic relationship, the grass you crush is greatly inhibited, perhaps even killed, while you continue unaffected and unaware of the interaction you’ve just had. Obviously, Slowpoke and Shellder are both greatly affected, which immediately rules out amensalism, but I thought it warranted mentioning.


Commensalism: The Boring One

Commensalistic relationships are basically a step up from amensalism, one party benefits while the other remains relatively unaffected, neither helped nor harmed. These relationships are rather uneventful (hence the title), and are usually limited to interactions where one organism use another for transportation or housing. For example, mites will often occupy different organisms such as flies for transport, never feeding off of them or causing bodily harm. Some organisms will even use the body of another postmortem for housing, such as when hermits use the shells of deceased gastropods for homes.


Free rides are hard to find, both in life and in nature.

Returning back to the Slowbro-Shellder Interaction, it’s fairly clear that Slowbro is indeed being harmed by Shellder biting down and remaining attached to its tail. Although, one could argue that Slowbro isn’t being harmed since, according to the Pokémon Silver Version PokéDex, “Naturally dull to begin with, it lost its ability to feel pain due to Shellder’s seeping poison.” However, just because an organism cannot feel the harm being inflicted upon it, does not mean it is not being harmed. Leeches release an anesthetic when they feed, allowing them to feed unnoticed by the host for hours until full. If I were to inject my sleeping roommate with an anesthetic, then stab him repeatedly in the gut as I tried to remove his kidney to sell on the black market, you would say I was harming even if he didn’t feel a thing. Not that I would ever do such a thing…

So case closed then. Slowpoke is very clearly being harmed. Shellder is a parasite. So we can completely rule out mutualism as well, right? Well, things are more complicated than that.


Parasitism: Violent Exploitation in the Natural World

Contrary to popular belief, parasites do not kill their host, or at least they do not intend to kill their host. You see, the parasites are locked in a special kind of symbiotic relationship, in which they derive sustenance from their host and thus will do everything in their power to keep them alive. If the host dies, the parasite will die most likely unless they can find a new body to mooch off of. That’s not to say that parasites won’t give the host a rough time, often the presence of a parasite can be debilitating to the host, perhaps killing them slowly rather than right then and there. This can be done through a number of methods – depriving the host of nutriments to feed itself, releasing waste products that can have deleterious effects to the host’s body, physically burrowing into and altering the structure of organs and tissues. In short, the fitness (survivability) of the host is sacrificed in order to advance the fitness of the parasite. The host could be on the brink of death but as long as the parasite can continue to survive, the relationship will continue.

Often when a parasite does kill its host it is either to fulfill a reproductive need, such as the lancet liver fluke which infects ants and compels them to hang to the ends of grass to be eaten by rabbits so to continue their life cycle, or it has accidently infected the wrong organism, one that has not evolved the immune defenses to keep it alive and functioning, as is the case with most fatal diseases that make the jump from animals to humans.


Ants are not the only victims of mind control, liver flukes influence the behavior of other organisms, including snails.

As we determined earlier, Slowbro is indeed harmed by the presence of Shellder, and Shellder does increase its fitness significantly attaching itself to Slowpoke, not only giving it free transportation, but also free food from feeding off of Slowbro’s scrapes, as well as the juices that run from its tail. Even the Bulbapedia page that I’ve pulled the PokéDex entries from states in the origins that “Its parasitic relationship to Slowpoke may be inspired by leeches.” So there you have it, confirmation from the top source of Pokémon information.

However, I have come to a different conclusion.

We must recognize that nature will not always fit so easily into the boxes we’ve constructed for it. Scientist often find trouble correctly labeling symbiotic relationships, perhaps at first seeing one as purely commensalistic only to later find that the other organism is being helped in some way. This gets even messier when trying to apply real-world logic to a videogame, a videogame that isn’t even consistent with its own rules and logic, as despite its various PokéDex entries, Slowpoke’s in-game evolution into Slowbro is completely independent of any interaction with Shellder.

Yes, Slowbro is harmed by Shellder, but I would argue that it is also helped, that Slowbro’s fitness increases when “infected” by Shellder.


If Ticks Gave Us Superpowers: Mutualism

The faint glimmer of hope that the natural world isn’t all doom and gloom is mutualistic symbiosis, an interaction between two organisms in which both parties benefit from the relationship. This reciprocal altruism often increases the overall fitness of both individuals, a great example can be found with the mutualistic relationship of sea anemones and hermit crabs – which are also an inspiration for Slowbro’s design. In the wild, certain species of hermit crabs attach sea anemones to their shells. In this relationship, hermit crab’s fitness increases by having an additional defense against predators – an array of stinging tentacles protruding from its back. Likewise, the sea anemone’s fitness also increases, as it is not only mobile (a great advantage for a normally sedentary species), but can also feed off the scraps if the hermit crab’s food (much like a certain grey-shelled Pokémon we know).


The sea anemone gets a free ride, the hermit gets added protection. Everybody wins!

In the previous section we have already accepted that Shellder is harming Slowbro, that part is indisputable. But I would argue that Slowbro is helped more than it is harmed in its relationship with Shellder.

Firstly, Slowbro’s stats improve significantly upon evolution via Shellder, even more so when Mega-Evolved. Now, one could chalk thus up to simple game mechanics and claim that this increase in stats is not unique to Slowbro, and they would be right. However, Slowbro does undergo additional changes in its physiology and behavior. As Slowpoke, it walked on all fours, but now with Shellder attached it can stand upright. Additionally, it receive additional powers from Shellder’s attachment, as the Black and White PokéDex states, “Though usually dim witted, it seems to become inspired if the Shellder on its tail bites down.”

Lastly, I point to my final piece of evidence – Slowking. This often forgotten secondary evolution of this docile Pokémon also falls victim to Shellder’s parasitism. However, Slowpoke only evolves into Slowking when Shellder bites down on its head, giving the once seemingly senile Pokémon an ability few Pokémon outside of legendries have – speech. In fact, Slowking gains full human-levels of intelligence by simply donning a Shellder cap.


“Slowking undertakes research every day in an effort to solve the mysteries of the world. However, this Pokémon apparently forgets everything it has learned if the Shellder on its head comes off.” – Pokémon Ruby and Sapphire Versions

Slowking undertakes research every day in an effort to solve the mysteries of the world. However, this Pokémon apparently forgets everything it has learned if the Shellder on its head comes off.

Classified as the Royal Pokémon, Slowking also stands upright, and has intelligence comparable to award-winning scientist, even conducting scientific research. Think about it, a Pokémon is doing scientific research and publishing papers. A small reminder that moments ago this same Pokémon was sitting by a body of water, too lazy to hunt for prey and merely fishing with its tail hoping that it something will bite.

The secret seems to lie within Shellder’s venom, whose effects increase the mental abilities of Slowpoke, producing a moderately more adept yet still docile organism in Slowbro when just attached to the tail, and an intelligent being when latched directly above the brain as is the case with Slowking. Either way, the overall fitness of Slowpoke is increased significantly, ranging from just being able to obtain food more easily to literally becoming self-aware.

Thus, while Shellder may harm Slowbro initially, the perhaps unintentional effects of its venom on its host indeed brings a plethora of benefits to Slowbro and Slowking. It is neither strictly a mutualistic nor parasitic relationship, but an odd hybrid of the two. In our world, it would be like if ticks gave us superpowers when they feed on you, instead of Lyme disease.

The Slowpoke line is a fascinating line to study, and provides great insight on the various interactions between Pokémon species that the games don’t often shed much light into. But with a little over analysis and speculation, we can make some sense of this, at times often, senseless world.

Cinnabar Island: Rebuilding the Ruins – Ecological Succession

Two years after the events of Generation I, our young protagonist returns to the esteemed island of Cinnabar only to find the place in ruins. A volcanic eruption has all but destroyed any sign of life or civilization on the island. People and Pokémon have fled for the Seafoam Islands, and the only sign of mankind’s reconstruction is a lone Pokémon Center. But when will Nature reclaim her territory and begins its own reconstruction. Chances are that she already has, the very literal seeds of her conquest were sown long before any human broke ground on the Pokémon Center. Although we may not witness it in the games, rest assured that the powers of ecological succession will restore Cinnabar to a flourishing paradise. Give or take a few decades.

At the risk of personifying Nature, ecological succession the process through which she reclaims lost territory or settles on new. There are two types succession, primary and secondary. In primary succession, Mother Nature is on the offensive, colonizing new territories that often devoid of vegetation and soil, just bare rocks and maybe cooled lava flows. Primary succession commonly occurs after a volcanic eruption, such as the one that took place on Cinnabar Island, as well as in areas where a glacier has just retreated, revealing what is often a bare lifeless layer of rock and stone.


To carry a weary metaphor, the first wave involves a hardy group of organisms called pioneer species which pave (or rather, un-pave) the way for later organisms by breaking down the rocky layer and establishing a thin layer of soil for which other more needy plants can use to dig their roots in and further the process. Abiotic factors (non-living components of an ecosystem) also play a part in eroding the solid exterior. Most pioneer species are organisms that require little or no soil to grow and are usually extremely resilient and adaptive, organisms such as lichens, fungi, algae, whose seeds can be carried by the wind easily and land in these decimated areas moments after the surface is exposed. Microorganisms begin cycling nutrients in the ecosystem to provide a basis for important biogeochemical processes, such as nitrogen-fixing bacteria which kick start the nitrogen cycle.

Over time, an ecosystem will form with increasing complexity. Larger organisms will move in and fill empty niches. Trees will take to the skies with a thick layer of soil to support them. This process can take as little as a few decades to up to millions of years depending of the severity of the disaster.

Secondary succession is often the quicker process, taking place in an area that has suffered a less catastrophic disaster in which substrate is left intact, such as a forest fire or human activity like deforestation. In these scenarios, soil and most of the other necessary components are still in place and thus the ecosystem can more easily recover.


Whether primary or secondary, ecological succession showcases the resiliency of life. Plethora of natural disasters and mass extinction events have tried to extinguish Earth of this unique phenomenon we call life, and yet every time Nature rebuilds itself and flourishes. Even if we are a blink in the evolutionary annals, there is something comforting in knowing that life itself will continue long after humanity has moved on, perhaps until the Earth itself is consumed by the Sun. In the end, life always finds a way.