Tag Archives: alola region

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.



Why UB-01 Might Change Everything We Know About Pokémon Forever

Two new “Pokémon” have garnered quite a bit of attention following the release of the latest trailer for Pokémon Sun and Moon. Within seconds of release the Internet was abuzz with speculation. What is Type: Null? Are Ultra Beasts even Pokémon? Is UB-01 Lillie?

I considered waiting until more information was released, possibly even until the games themselves came out, to write about synthetic biology throughout the Pokémon Games, but as I was reading through my daily Reddit feed I had a revelation of sorts and I couldn’t contain myself. I will still write a more extensive post on synthetic biology in the future, probably after I’ve had a chance to play through the game and familiarize myself with all its details. But for now, I will focus on the two new “Pokémon” we’ve been introduced to.

Let’s start with Type: Null. I’m sure I wasn’t the only one scratching their heads once it was revealed. It’s typing was Normal yet it said Type: Null above? Weird? Even after rewinding the trailer I believed that it was a massive flop on some poor video editor’s part for leaving in the working name for this new Pokémon. But I eventually realized that in fact the Pokémon Company had thrown us yet another curve ball.

As many people have pointed out, Type: Null appears to be a chimera. However, most of the fans that brought up this point seemed to be referring to the mythical beast. While Type: Null does appear to draw inspiration from the mythical part-lion part-goat part-snake beast, I would argue that Type: Null is very clearly a botched attempt at creating a tetragametic chimera. In biology, a chimera is an organism composed of cells originating from different zygotes, or fertilized eggs. This is different from a hybrid, which is often the result of two different species crossbreeding to create a single zygote.


In animals, a chimera can typically be achieved through one of two ways. The first is by combining multiple zygotes. This can occur naturally in the womb in rare occasions, allowing the resultant organism to be its own twin in a sense. The second involves the transplant of cells or organs from one organism to another. For example, heart cells could be implanted inside of a pig in order to grow functioning heart tissue. This may seem like science fiction but there are currently efforts to do this exact thing. And despite a recent ban in the funding of such experiments by the National Institutes of Health, researchers are still pursuing human-animal chimeras1. This will come into play later, so keep that in mind.


Most chimeras are not visibly identifiable, in fact you could a chimera (or even be one yourself) and never know. However, resulting organisms on occasion exhibit unique traits, such as hermaphroditism, having both male and female genitalia. Pigmentation and fur color are also common changes.

But the games obviously have links to alchemy.

Well, that may be well a true. There is a great deal of alchemy references scattered throughout the games. But there has also been quite a number of biology references as well. Oricorio (Darwin’s finches), Alola forms (divergent evolution), and let us not forget the themes of invasion, particularly in respect to introduced species such as Rattata, Meowth, and Yungoos. While alchemy does play a role in the game’s lore, this particular region seems to have a lot more going on just from an ecological and biological viewpoint than previous installments. Look at this blog’s archive for evidence. I haven’t been able to write a non-Sun and Moon article in ages due to this constant stream of new information.

Additionally, what is alchemy but a proto-science of sorts? It is essentially the precursor to chemistry in an age before scientific knowledge became widespread. And chemistry often plays a huge role in many fields of biology, including genetics and the budding field of synthetic biology.

So Type: Null is a chimera, perhaps both in a mythical sense and a genetic one. But what about UB-01?


We know little about Ultra Beasts except for that they possess mighty powers and could pose a threat to humans and Pokémon. Additionally, we are told that the newly revealed Aether Foundation is performing extensive research on these mysterious creatures and that there may be more than one of them.

Very clearly, it is implied that Ultra Beasts are not Pokémon. The description choses its words carefully, deciding to say that they pose a threat to humans and Pokémon rather than humans and other Pokémon. Additionally, UB-01 is not even listed with the other Pokémon on the website but instead with the characters. Weird.

Moreover, UB-01’s description tells that evidence of a survival instinct has been observed in this creature and that it’s movements resemble that of a girl. And UB-01 just so happens to have a striking resemblance to a certain female character who is described first and foremost as mysterious. That is no coincidence.

In light in this evidence, many have concluded that UB-01 must be Lillie. And in the context of alchemical themes already present, such a transformation seems likely. However, I don’t think that Lille is UB-01, and this is why I believe Ultra Beasts might change the Pokémon World forever.

UB-01 is a Human-Pokémon chimera.

Or, possibly, a hybrid, depending on how it was made. But the core concept is the same. UB-01 shares the genetic material of a Pokémon (possibly many Pokémon) and a human. That human is likely Lillie.

Moreover, I believe that there is some connection between the Ultra Beasts and the Aether Foundation. It is possible that this organization may have created the Ultra Beasts in an attempt to create a creature with the mind of a human but the powers of a Pokémon. One might say that this could be the ultimate being.

This may sound farfetched, but there is precedent in the Pokémon World for these types of experiments. As early as the first generation we have Porygon, the Virtual Pokémon, an entirely manmade Pokémon. Then we have Mewtwo, a botched attempt at creating the most powerful Pokémon from the genetic template of the very first Pokémon. In Generation V we have Genesect, an ancient Pokémon modified by Team Plasma. What’s more, we already know from several PokéDex entries that Pokémon do in fact have DNA it appears to operate in the same manner as it does in our world. And considering that there is an extensive history of experimental testing concerning Pokémon, is it really too much of a stretch to assume that someone would attempt to bring the two creatures together as one. Many already speculate that humans are in fact Pokémon themselves, or at least descended from them similar to how humans are descended from a common primate ancestor. And in our own world there have been attempts to reunite our kinds.

The Humanzee, a hypothetical hybrid of human and chimpanzee, has been the inspiration of many science fiction stories and internet legends. However, there is at least one documented attempt at creating such a creature in the 1920s by scientist  Ilya Ivanovich Ivanov, who conducted experiments to impregnate female chimps with human sperm. His attempts failed, but many still believe that such a hybrid is genetically possible under right conditions.

There is appears to be a consensus across fan forums that the Aether Foundation is not as benevolent as they seem, but what if it goes further than some simple Shyamalan twist? Why do you think they have their ow artificial island in the Alola region? Perhaps to perform experiments which would otherwise be illegal or at the very least frowned upon if they took place on the land. Maybe their intentions started out as pure, perhaps creating the chimeras in the hope of providing needed human tissues and organs in Pokémon, only to later turn toward more morally ambiguous intentions.

One final thought. Back to the humanzees. A big ethical questions which has prevented many researchers from attempting this has been whether or not this result being would have, for lack of better words, a soul. Many predict that such a creature would at best come out mentally retarded, and thus it would be immoral to knowingly bring a being who may or may not have a soul into the world only to suffer out what would probably be a short and agonizing life.

The website mentions a curious detail about UB-01. No one knows whether it has a will of its own or any emotions.

Just a thought.

Alolan Rattata: A Tale of Mice, Men, and Mongoose

Do you remember the old nursery rhyme about the old lady who swallowed a fly?

For the uninitiated, the story goes as follows: There was an old lady who swallowed a fly. For what reasons she swallowed a fly we do not know. Perhaps she will suffer the consequences of her poor dietary decision. The woman, perturbed by the buzzing of the live fly she just consumed, proceeds to swallow a spider in order to catch the fly. The spider appears to successfully apprehend the fly, however, the spider has begins to wriggle and wiggle and tiggle inside her. Having learned nothing from her previous two experiences with swallowing live animals, she goes on to swallow a bird to catch the spider, then a cat to catch the bird, a dog to catch the cat, a cow to catch the dog, and a horse to catch the cow, at which she finally succumbs to her gluttonous behavior.

A child-appropriate bedtime story if there ever was one.

But ethical questions surrounding the grime nature of this nursery rhyme aside, the tale of the old lady who swallowed a fly provides great insight to the core of human nature. We tend to have limited foresight, unable to predict the consequences of our actions even when we have prior experience with them. Our carelessness towards solving problems hastily with poorly thought out solutions instead of taking the time to think critically and rationally about the situation at hand.

This tendency is best exemplified when it comes to the issue of invasive species. A similar pattern emerges every time mankind unwittingly introduces a foreign species to a new land. An alien organism is unleashed into an ecosystem that evolved without its influence. Consequently, the invading species propagates and decimates the native populations. So, in order to counter effect of the invading species, we introduce another foreign species into the ecosystem. The new invader propagates and decimates the native populations as well, and the cycle begins anew. Like the old lady, we assume that we can quell the fly’s buzzing by swallowing a spider without seeing that we’ll just to have to deal with the spider.

You’re probably thinking, That would never happen in real life. Nobody is that stupid. Allow me to point to the Hawaiian Islands, certainly no strangers to foreign invaders (See The Feral Cat Problem: The Unfortunate Truth About Alolan Form Meowth). During their expeditions, European explorers were accompanied by an uninvited guest, Rattus norvegicus, known colloquially as the brown rat. These furry stowaways followed humans on their many expeditions throughout the world, colonizing many remote islands alongside their human counterparts. Hawaii was no exception.


Rats are essentially the crème de la crème of invasive species. One could say that they were specifically designed to conquer foreign ecosystems. For starters, rats are very adaptable and are able to live in a wide range of environments. In addition, rats eat everything. That is not hyperbole. If it has any nutritional value, a rat can and will eat it. But perhaps what makes them so successful as an invasive species is their ability to reproduce exponentially. Rats reach sexual maturity at five weeks, females ovulate every 4-5 days, and they have a gestation period of only 22 days with as many as 20 babies in a litter1. A single pair of rats can produce as many as 2,000 descendants over the course of a single year2. Indeed, if there was ever an animal best equipped to conquer the world, the rat would be it.

And unsurprisingly, once these furry invaders set foot on the pristine island ecosystem of Hawaii, there population skyrocketed as they ravaged the countryside like barbarian tribes ransacking the Roman capital. They pillaged agricultural fields, disrupted local ecosystems, destroyed native bird nests, and spread a slew of new diseases and parasites which took their own toll on the native populations, animal and human alike.

The metaphorical fly had caused quite a bit of damage, so to quell its buzzing, in 1883, the sugar industry introduced mongooses to sugarcane fields with the hope of curbing the damage done by the rat infestation.


The mongoose is a native of India3. Like rats, mongooses are far from picky eaters. They will essentially feed on anything that they are able to successfully swallow. Hawaii with its diverse plant and animal life was an open buffet. Why stick to mere rats when you can dine on Hawaiian delicacies such as petrel hatchings, sea turtle eggs, and practically every moving object in sight.

Moreover, mongooses are able to adapt to a variety of environments, thus giving them unlimited range to hunt throughout the islands.

While their impact on rat populations has been rather insignificant, mongooses have annihilated native populations. They have all but exterminated the native lizard population4, driven several bird species to near extinction, and caused a reported $50 million in damage5. The Hawaiian goose, also known as the nene, had an estimated population of 25,000 in 1778. By 1952, that number had dropped to 306.


To make matters worse, mongooses are surprisingly intelligent, and tend to avoid most traps, especially when prey is abundant, and it is always abundant.

And as a final piece of cruel irony to this already depressing tale, rats are nocturnal creatures, coming out mostly at night, while mongooses are diurnal, being most active during the day7. The two species rarely came in contact with each other.

[Queue Mario Fail Music]

Goes to show that a little research can go a long way. #TheMoreYouKnow

In perhaps the most obvious parallel to its real-life counterpart yet, the Alola region is also victim to the narrow-sightedness of a few individuals. Yungoos, the Loitering Pokémon, is not native to Alola, but was introduced to the islands in order to deal with the overpopulation of a “certain other Pokémon”. It has now since been revealed the “certain other Pokémon” to be none other than Alolan Rattata, now a dual Normal-Dark Type, fitting for such a destructive creature.


Perhaps like with Alolan Meowth, the inclusion of this unfortunate real-life reference will bring attention to a critical issue plaguing the Hawaiian Islands, and maybe begin a conversation about the way we approach fixing our messes.

Maybe we should tell our children the tale of the old lady who swallowed a fly as a cautionary tale, so that they do not make the same mistakes we do.

The Feral Cat Problem: The Unfortunate Truth About Alola Form Meowth (Pokémon Sun and Moon)

Hawaii has a cat problem.

The Hawaiian Islands are no strangers to invasive species, European colonization has introduced a plethora of foreign creatures to its delicate ecosystems. Mosquito eggs stowed away in pools of water only to hatch in an environment that evolved without them. Argentinian ants added Hawaii to their list of conquer territories when cargo ships unintentionally brought them to the islands, as did fire ants who also thrived in the defenseless new world. Naturally, snakes and rats found their way aboard human ships as well, humanity can’t go anywhere without its two greatest enemies. But perhaps one of the most devastating forces to set foot on the shores of Hawaii (besides Europeans) is felis catus, the domestic cat.

Likewise, it is only fitting in a game that has already borrowed so much from real life to acknowledge the feral cat problem plaguing Hawaii in the form of Alolan Meowth.

Like its real life counterpart, Meowth is not native to the Alola region. The species was introduced to the islands as a gift to the royal family from a distant unidentified region, most likely Kanto. Through a combination of selective breeding and excessive pampering, Meowth evolved into its Alolan form which reflects its terribly destructive lifestyle. Once the monarchy fell, the Meowth turned to the wild and became what we would call a feral animal, a species that was initially domesticated but has since returned to the wild.

feral animals

In the time since the fall of the monarchy, Meowth have become quite common across the islands, much like their real-life counterparts who currently inhabit all eight Hawaiian Islands. The cats have no predators and sit comfortably atop the food chain, free to feast on an ecosystem that evolved independently of its influence and thus is open season for one of evolution’s finest predators.

While their Pokémon counterparts evolved into a different form, feral cats on Hawaii, as in most places, have remained relatively unchanged, appearing no different from domesticated cats in everything except behavior. As any cat owner knows well, even domesticated cats are fairly independent and are nowhere as needy as, say, dogs. Despite years of selective breeding, cats are still, essentially, tiny tigers that you keep in your house. This is bad news for wildlife.

For starters, in the time since their introduction, feral cats have wreaked havoc on island ecosystems. Feral cats are responsible for the extinction of 33 island species, and currently pose a threat to 8% of critically endangered birds, mammals, and reptiles. Feral cats on Hawaii have been especially devastating towards local bird populations. Exact numbers are difficult to come by mainly due to the rarity of the birds, but a recent study conducted in 2013 by the University of Hawaii, National Park Service, and the U.S. Geological survey monitored the burrows of the Hawaiian Petrel, a bird native to the island. Out of the fourteen burrows monitored, feral cats were found to be present in eight. However, feral cats are not just a problem on islands. Over 2.4 billion bird deaths have been attributed to your feline friends in the United States alone.

hawaiian birds

As we have seen from previous gameplay trailers, the Alola region is already home to a diverse population of birds, particularly the various forms of Oricorio. It isn’t much of a stretch to assume that the presence of Meowth has had its own devastating impact on the Alolan ecosystem. Who knows how many native species have suffered at the hands of Meowth, or have even gone extinct from predation? Oricorio and its various forms may currently be endangered like many native Hawaiian species. If the games intend to continue their streak of mirroring real life, then it is quite possible that Oricorio’s endangered status may be reflected in its rarity. The player may only be given a single opportunity to capture each form, similar to legendaries and a few other Pokémon such as Volcarona and Kecleon.

However, predation is not the only threat that feral cats have introduced to the islands. Cats can serve as hosts for Toxoplasma gondii, a parasite that requires cats to complete its life cycle. Feral cats can unwittingly carry the parasite from ecosystem to ecosystem, spreading its infectious eggs through its feces. This can often contaminate water sources—marine and freshwater—as well as spread on land where bird and even humans can fall victim to it.


In the Pokémon World, we already have Pokérus which is highly beneficial. But considering that feral cats are often hosts for diseases, is it possible that Alolan Meowth will be instrumental in spreading a new PokéPathogen? Or perhaps it was Meowth that initially introduced Pokérus to the Alola region, however, due to the island’s isolation, the normally benign virus is actually harmful to the native population, similar to how island populations in our world are often susceptible to diseases that seem harmless to us since we have built an immunity to them over the years.

While it is fun to speculate on the implications of a feral species running rampant in a fictional ecosystem, the issue of feral cats is serious and needs to be addressed. Hopefully, by just the inclusion of this Alolan form, more attention can be brought to the destructive power of our feline friends when we act carelessly on their behalf.

For more information on feral cats and other invasive species in Hawaii, check out the Hawaii Invasive Species Council’s website, as they were a great resource for this blog post, as was the American Bird Conservancy.

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.