Are Pokémon Animals?

I have mentioned Pokémon before in my articles, but have only in passing. I now think it is time to take a scientific approach and look at these interesting, fictional organisms through the lens of science. Before we explore the title question, we first need to define what constitutes an animal. Animalia is one of the seven (as per the most recent revision of biological classification) kingdoms of life. The others are Plantae, Fungi, Protozoa, Chromista (diatoms, brown algae, etc.), Archaea, and Bacteria. Animals are multicellular, eukaryotic, heterotrophic organisms that lack cell walls. The cells are grouped into tissues, with each tissue having a specific purpose. Sponges, which are essentially just a clump of cells without any body symmetry, are the exception. As there are no sponge Pokémon to date, we do not have to worry about this. Animals must be able to move voluntarily and independently at some stage in their lives and develop until they reach a fixed body plan.

Protista is used here rather than Protozoa, but they both constitute the same types of organisms.

So, are Pokémon animals? The answer is, it’s hard to tell, but they probably are. There isn’t a way to know whether or not a Pokémon’s cells have cell walls because there is no data about their cellular structure, so we don’t have this to go on. All Pokémon appear to have body symmetry, one exception being Ditto. Ditto throws a wrench into the equation because it has an amorphous form, but can reorganize its body structure to take on the appearance and abilities of any other Pokémon. However, Ditto may be the result of a failed human experiment to clone Mew, the ancestor of all Pokémon. For this reason, we will exclude Ditto from our discussion because it was created through human intervention and did not evolve naturally. We’ll come back to Pokémon “evolution” later.

This Ditto is sad because it doesn’t fit in.

Another stumper is when we start to consider Pokémon diets. Most seem to be heterotrophs, like animals, but some are described feeding exclusively on rock or metal (lithotrophs), while some can photosynthesize (autotrophs). Heterotrophs are organisms that must use organic carbon sources for energy because they cannot fix it themselves like other organisms. Plants can. They convert light energy into more complex organic compounds through photosynthesis. A handful of Pokémon actually are able to sustain themselves on nothing more than electricity. Does this mean that these rock, metal, and electron eating Pokémon species are not animals? Not necessarily. We haven’t learned all there is to know about Animalia yet and it is possible that there are animals yet to be discovered with highly diverse diets that deviate from the standard heterotroph. Many of Pokémon are also capable of enjoying Pokémon food that is made from berries and other organic material, as well as treats such as Pokéblocks (candy for Pokémon) or Poffins (a pastry-like Pokémon treat). Even Pokémon of the Ghost Type, the majority of which appear to be non-corporeal beings, will take Pokémon food if it is offered.
Many real life animals will often consume non-organic substances such as clay to supplement their diets or neutralize toxins in their food. However, this alone is not enough to sustain them. Animals MUST ingest other living things or their products to survive. There is nothing that says that the stranger Pokémon species need to eat something other than iron ore or enough dirt to make an entire mountain.

Aron, the iron eater.

Larvitar, the mountain eater.

Some Pokémon are very plant-like. These are the Grass Type Pokémon. Many of them have abilities like Chlorophyll or Solar Power. Some of these Pokémon species look more like animals that others, though, so how can they be plants? The answer is: they don’t have to be if they participate in mutualism. Mutualism is a form of symbiosis in which both parties benefit from an interaction. It could be that all of the photosynthesizing Pokémon are hosts for special algae or other organisms that can fix carbon so that it is usable. In return, these Pokémon provide their little sun factories with precious nutrients. A few existing animals do this too, so it’s not really that out there to consider it in Pokémon.
Pokémon fill all the requirements of being animals except for their diets. We are still learning much about many strange metabolisms and food preferences in the animal kingdom, so I don’t think we can exclude Pokémon from Animalia just for this, as I mentioned above. We’ll keep exploring their biology.
Getting back to that “evolution” thing. Most, but not all Pokémon, go through “evolution”. Pokémon “evolution” is different from the Darwinian evolution that we know and love. It is predictable and occurs within the same individual. Pokémon evolution is analogous to metamorphosis in the real world. In fact, there are some Pokémon species that perfectly follow metamorphosis in real animals like butterflies, moths, and frogs. Pokémon can also be confirmed to have a Darwinian evolutionary history simply because of the fact that there are “ancestor Pokémon” like Mew that contain the basic genetic blueprints of all future Pokémon, and “fossil Pokémon” such as Omanyte and Anorith. Natural Selection seen in the Pokémon world emphasizes the presence of Darwinian evolution as well. Different regions provide a wide variety of habitats and the Pokémon found in these areas are well adapted to the conditions. This suggests that there is a process of adaptation over generations of Pokémon that resulted in the ones we see today that thrive in their respective environments.

Mew, the ridiculously cute ancestor of all Pokémon.

At this point, I feel that is safe to place Pokémon within Animalia. If they existed, they would make up their own separate phylum. Pokémon are incredibly diverse, and many don’t even look like they are related at all. But, just take a look at our own phylum, Chordata. There is a ridiculous amount of variation within it. Chordata contains animals ranging from simple, filter feeding tunicates, all the way to elephants, whales, birds, snakes, and of course, humans. Pokémon can take the form of gargantuan, dragon like creatures, or something as out there as a living pile of garbage. As briefly mentioned, there are different Types (18 in all) of Pokémon. Pokémon of the same type share similar abilities, weaknesses, and strengths. There is a Primary Type, and a Secondary Type. These Types could be thought of as analogous to classes within biology. Secondary Types would comprise the subclasses. For example, a Pokémon could be of the Fire Type class, but also belong to the Ground Type as its subclass.

The 18 Types of Pokémon.

But why did I choose class rather than some other higher or lower taxonomic ranking? It is because class seems to fit the variation observed within Pokémon types quite nicely and is a good reflection of a class such as Mammalia (our class). Every member of Mammalia is, by definition, a mammal. The blue whale is the most massive animal to have ever lived on this planet, yet falls into the same biological class as the tiny, extinct Batodonoides vanhouteni (a shrew-like mammal) and egg-laying mammals like platypuses and echidnas. Though they differ greatly, all these animals have a handful of defining features that set them apart from any other class. As is their namesake, all mammal species are capable of producing milk through mammary glands. Likewise, a Pokémon belonging to a specific Type will also share similar traits with fellow members of that Type that others don’t possess (unless those others have it as their Secondary Type/subclass). Water Types, for example, all appear to have increased fitness in rain and become weakened and dehydrated by hot, dry weather.

Swampert is a Water/Ground Pokémon. This means that its Primary Type is Water and its Secondary Type is Ground. Because of this, it has the unique traits of both Types. It is also one of my favorite Pokémon!

As with animals, there are many other ways to rank Pokémon taxonomically. We could break them into phyla, orders, families, genera, and individual species. Analysis of all taxonomic rankings like this would probably go on for pages and pages, so we will cut it off at classification by Type and the educated assumption that Pokémon are in fact part of Animalia. Even though these creatures are not real, it is always fun to speculate and dig into the “what ifs”. This curiosity and exploration is the whole basis for science fiction, one of the most popular genres of all time, and it enriches our imaginations and our lives.

References:
1. Myers, Phil. “Animalia (animals).” Animal Diversity Web. Univerisity of Michigan Museum of Zoology, 2001. Web. 04 Dec. 2015.

2. Ruggiero, Michael A., et al. “A higher level classification of all living organisms.” PloS one 10.4 (2015): e0119248.

3. Venn, A. A., J. E. Loram, and A. E. Douglas. “Photosynthetic symbioses in animals.” Journal of Experimental Botany 59.5 (2008): 1069-1080.

4. Trench, R. K. “The cell biology of plant-animal symbiosis.” Annual Review of Plant Physiology 30.1 (1979): 485-531.

5. Barbo, Maria S. The Official Pokémon Handbook. New York: Scholastic, 1999. Print.

6. “Type.” Bulbapedia. Web. 23 Dec. 2015.

7. Bloch, Jonathan I., Kenneth D. Rose, and Philip D. Gingerich. “New Species of Batodonoides (lipotyphla, Geolabididae) from the Early Eocene of Wyoming: Smallest Known Mammal?”. Journal of Mammalogy 79.3 (1998): 804–827.

Photo Links:
1.http://www.tanelorn.us/data/mycology/myc_kingdom.htm

2.http://www.aminoapps.com/page/pokemon/2097774/ditto

3.http://www.serebii.net/card/risingrivals/057.shtml

4.http://bulbapedia.bulbagarden.net/wiki/Larvitar_%28Pok%C3%A9mon%29

5.http://attackofthefanboy.com/guides/get-mew-pokemon-red-blue-yellow/

6.https://people.rit.edu/~dap4092/230/project1/basics.html

7.http://www.deviantart.com/art/Swampert-118686577

Could “The Last of Us” Really Happen?

UPDATE 4/19/22: Newer research has suggested that the ants that are infected with O. unilateralis are not in fact controlled via manipulation of the brain. Rather, there seems to be a chemical means by which the fungus forces the ant to bite the leaf vein. The study found no evidence of fungal cells inside the actual brain. However, hyphae were abundant throughout the head of the ant and the rest of its body, including inside the muscle fibers themselves, creating a complex network. The exact mechanisms behind the behavioral manipulation are still not known and more studies need to be done. With that in mind, please know that I am discussing the structure and function of ant brains in this article, as it helps exemplify the differences between an insect and vertebrate brain for the purpose of speculation.

For those who don’t know, The Last of Us is a dark, yet beautifully crafted survival horror game that explores what the world would be like if the majority of the human population were infected by a mutated strain of Ophiocordyceps unilateralis. This video game is critically acclaimed for its storytelling, graphics, and gameplay. It is considered a masterpiece by most of its reviewers and by its players. From the little bit I have played, I would absolutely agree. There are few developers that are able to take a real world scientific event, such as an insect being manipulated by a parasitic fungus, and implement the core concept realistically in a video game. Naughty Dog, the developer of The Last of Us, does this fantastically well.

Joel and Ellie are the game’s core characters

Ophiocordyceps unilateralis is in fact a real fungus. This species (actually a whole complex of species referred to collectively as Ophiocordyceps unilateralis sensu lato, meaning “in a broad sense” – I will refer to this species complex just as O. unilateralis from here) specifically targets ants, generally of the Camponotus genus, and takes over their bodies in order to move them to a location with ideal conditions for its reproduction. One of the most interesting things about this fungus is how precisely it manipulates its host. A 2009 study by Andersen et al. in The American Naturalist found that ants infected with O. unilateralis almost always died gripping a vein on the underside of a leaf (98%) and that this location was significantly more towards the north-northwest side of the plant than any other direction. Camponotus ants were found almost exclusively at a height of 25 centimeters from the forest floor, while closely related Polyrhachis ants were seen at a mean height of 78.43 centimeters. This kind of behavioral control is known as an extended phenotype. The gene expression of a parasite within a host’s tissue causes aberrant host behavior that increases the parasite’s fitness. Keep in mind that the ant species in the study colonize the canopy, not the forest floor, so this is extremely complex behavioral manipulation. Under the fungus’s control, these infected ants are traveling very far from their initial location. Many infected ants will often die in areas where others already have because the conditions in these places are favorable for O. unilateralis. This leads to places, called graveyards, that have a high density of corpses. Any healthy ant happening to walk through such an area will likely become infected by the deadly spores.

An ant with its jaws locked in a “death grip”.

When O. unilateralis spores come into contact with an ant, they adhere to it and start to penetrate its cuticle. After this, fungal cells start to infest the ant’s entire body and begin to alter its behavior. The infected ant then leaves the colony and starts the trek down toward the forest floor. Once a perfect spot is reached, the ant will bite the vein of a leaf and die with its jaws locked in place. This is known as the “death grip”, and keeps the ant from falling off the leaf. Any ants that end up dying within the colony due to infection will be carried far away by other workers. Within a few days, the stroma, or stalk, of the fungus will erupt from the back of its host’s head and develop a stromal plate that releases spores when mature. By this point, most of the ant’s original tissue has been replaced by fungus.

Saggital section of a dead Camponotus ant filled with fungus from The American Natrualist – W = white, Bl = black, O = orange, and P = pareithecial plate, which is where the spores originate. (The life of a dead ant: the expression of an adaptive extended phenotype. Andersen et al. 2009)

The ants in the video below are not Camponotus or Polyrhachis ants, and the fungus is not O. unilateralis so the hosts show a different behavior. However, it still illustrates the process well.

What a horror it would be if humans were susceptible to such a fate! The question is, could this actually happen? Let’s consider the ant brain for a moment. It has all the general features of a typical insect brain and is very simple compared to a vertebrate brain. However, ants have more well developed areas associated with memory and learning. These “higher” functions are controlled by the mushroom bodies. Mushroom bodies are much larger in worker ants than they are in the male soldiers. Workers must navigate varying spacio-temporal environments using multiple cues and also remember where food is and where home is. For ants, workers are the most “intelligent”. Still, one lone worker is of no use. It takes the whole colony to have a properly functioning and flourishing nest. An entire colony of ants, which can be up to millions of individuals, does not even come close to matching the complexity of a single human brain. If a fungus were to develop an ability to infect and alter the behavior of humans, this would probably take a ridiculously long time to evolve. Human beings would most likely not even be around any longer. But, let’s just roll with it and say that this could happen. What would it be like and how does The Last of Us compare?

Simplified ant brain from Recognition of social identity in ants (Bos and d’Ettorre, 2012).

We’ll start with the mode of infection. In the video game, people seem to become infected by breathing in the spores of the mutant O. unilateralis strain. Those who wear a special breathing bask in spore filled areas do not become infected. This appears to check out. Human skin is likely to be much less susceptible to becoming invaded by spores, simply because it is so much thicker and has many more layers than insect cuticle. Other fungi are able to infect hosts via inhalation (like some molds), so it would be no different for a mutant fungus; the infection would just result in a different pathology. So getting infected by this fungus is not in question if you breathe the spores in, but you can also fall victim if there is an exchange of bodily fluids, such as from a bite. This is logical as well. If the fungus has infiltrated an infected person’s system as in ants, bodily fluids like saliva and blood may contain fungal cells. These could easily be passed on to a healthy human.

What about the behavioral and morphological alterations? In The Last of Us, any infected individual, even in the early stages, is being driven by the fungus’ gene expression and aims to spread the spores or cells to as many others as possible. There are four main stages of infection from this mutant O. unilateralis: Runners, Stalkers, Clickers, and Bloaters. All of these collectively are referred to as the Infected (noun) in the game. Individuals who have just been infected are classified as Runners. They still cling to a shred of their humanity, however small, and try to resist the fungus’ behavioral control. However, if they are startled or as the infection progresses, they will snap and attempt to attack anyone nearby who is healthy. Stalkers are fully controlled by O. unilateralis and start to show fungal growth on the face. This fungus strain attacks the eyes first, so they have poor vision and begin to exhibit primitive signs of echolocation. In Clickers, the face has been fully engulfed by fungal growth and rendered the host completely blind. These Infecteds use clicking and screeching to crudely survey their surroundings within a small radius. The growth on the head and face forms a roughly dish shaped plate that helps to direct the clicks. Bloaters are the final stage and can take 10-15 years to develop. The entire body of this Infected is now covered in fungus, some of it showing bioluminescence, and is therefore very physically hardy. Bloaters are also able to throw sacs of toxic powder both as a defense and an attack mechanism. Once the host finally dies, whatever tissue is left of the former person crumbles and is used by the parasite to complete its growth and release spores.

The remaining tissues of the victim begin to crumble as the fungus spreads its spores.

Now to analyze the behavior of the Infected. All stages appear to seek out specific locations and stay there, unless stimulated to pass on the infection when a healthy individual is sensed nearby. This reflects the behavior of O. unilateralis controlled ants that travel until they find the optimal conditions for the fungus’s reproduction and then fix themselves to that spot. However, infected ants will leave the colony and do not show any aggressive behavior whatsoever toward other ants. Why would the Infected exhibit such an aggressive drive to bite or kill? We actually have a disease in existence that does just this. It’s called rabies virus. If rabies can infiltrate the brains of mammals and stimulate this type of behavior, it would not be a stretch to think that a mutant fungus could affect humans this way. Rabies in humans doesn’t present the same way that it does in other mammals; it resembles a bad flu, followed by agitated behavior and cognitive deficits, sometimes with hallucinations, delirium, and insomnia. Perhaps our mutant O. unilateralis would be able to incite the aggressive behavior seen in the games by affecting the brain in a similar way to rabies in non-human mammals. This could explain the Infecteds’ responses to healthy humans.

Clickers use crude echolocation to detect the presence of nearby humans and then go into a full sprint toward anyone they sense.

Runners display behavioral tendencies that would be expected. Since the fungus has only just started infiltrating the brain, it is not surprising that the victim would be scared and confused by what is happening. It makes sense that a person in this state would be very volatile and dangerous to approach. Stalkers tend to hide out of sight and only engage when someone lets their guard down. This is presumably because their vision is extremely poor and they must wait until the opportune moment in order to successfully attack. Clickers are harder to explain realistically. It would be highly unlikely that an Infected would suddenly develop the ability to navigate using clicks. This is a skill that must utilize learning and memory, parts of the brain no longer accessible to the victim. Very few humans are able to echolocate and those who are have refined their technique over years. Real world O. unilateralis is not able to direct ants to do things they are not already capable of; it simply takes advantage of abilities the insect already possesses. The sense that would be most beneficial to a Clicker is touch. Of course, sound is still an effective way of interacting with surroundings, but it would not be used for spatial navigation as in The Last of Us. This can be extrapolated to the Bloaters in the game as well, because they also use echolocation. All of these Infected will attack to kill. This is presumably because the fungus cannot kill immediately on its own, but can reach maturity faster in a dead body. So, when controlling a living human, O. unilateralis uses that person to its advantage by driving them to help speed up reproduction through the provision of corpses. If the host fails to make a kill, but manages to penetrate the skin of a healthy human, then the fungus still benefits because that person will become another Infected.

Bloaters take 10 to 15 years to develop and have hard fungal growth all over their bodies, giving them great resistance to blunt and penetrating forces.

Overall, the concept of The Last of Us is scientifically plausible, given enough time for O. unilateralis or a different species of Ophiocordyceps fungus to evolve the traits explored here. The intelligence and thought put into this game has given it so much more than most other video games can offer. These things make it different from your standard zombie apocalypse. It is scary because it feels like it could really happen, and this realness comes from its grounding in actual science. The infection seen in it is already a reality for many insects and other arthropods. They may not show the aggressiveness displayed by the Infected, but the behavioral manipulation seen in these animals is extremely effective at fulfilling the fungus’s needs. Maybe at some point in the future, the fictional scenario of The Last of Us could come to be. Who knows? The natural world is continually revealing so many things previously thought impossible.

References:
1. Gronenberg, Wulfila. “Structure and function of ant (Hymenoptera: Formicidae) brains: strength in numbers.” Myrmecological News 11 (2008): 25-36.

2. Evans, Harry C., Simon L. Elliot, and David P. Hughes. “Ophiocordyceps unilateralis: A keystone species for unraveling ecosystem functioning and biodiversity of fungi in tropical forests?.” Communicative & integrative biology 4.5 (2011): 598-602.

3. Hughes, David P., et al. “Behavioral mechanisms and morphological symptoms of zombie ants dying from fungal infection.” BMC ecology 11.1 (2011): 13.

4. Andersen, Sandra B., et al. “The life of a dead ant: the expression of an adaptive extended phenotype.” The American Naturalist 174.3 (2009): 424-433.

5. Pontoppidan, Maj-Britt, et al. “Graveyards on the move: the spatio-temporal distribution of dead Ophiocordyceps-infected ants.” PloS one 4.3 (2009): e4835.

6. “The Infected.” The Last of Us Wiki. Wikia, 2013. Web. 7 Oct. 2015. <http://thelastofus.wikia.com/wiki/The_Infected>.

7. “Signs and Symptoms – Rabies.” Centers for Disease Control and Prevention. Centers for Disease Control and Prevention, 15 Feb. 2012. Web. 08 Oct. 2015.

Photo and Video Links:
1.http://static.giantbomb.com/uploads/scale_large/9/93770/2419553-397060_386577108098888_427807760_n.jpg

2.https://i.guim.co.uk/img/static/sys-images/Guardian/Pix/pictures/2010/12/21/1292935214310/a-dead-worker-ant-004.jpg

3.http://ento.psu.edu/publications/DH1

4.https://www.youtube.com/watch?v=XuKjBIBBAL8

5.http://journal.frontiersin.org/article/10.3389/fpsyg.2012.00083/full

6.https://vignette.wikia.nocookie.net/thelastofus/images/3/3f/Infected_Final_Stage.jpg/revision/latest?cb=20130224030859&format=original

7.http://vignette4.wikia.nocookie.net/thelastofus/images/9/9d/Clicker.jpg/revision/latest?cb=20150928101722

8.http://vignette4.wikia.nocookie.net/thelastofus/images/8/8f/Bloater.jpg/revision/latest?cb=20150928101859

UPDATE: NEW CLOUDED LEOPARD CUBS!

UPDATE!!! 6/5/15
Four new clouded leopard cubs that were born in May at the Point Defiance Zoo & Aquarium in Tacoma, Washington are now officially on display! Go see them if you’re in the area! 🙂

http://www.king5.com/story/news/2015/05/19/1-week-old-clouded-leopard-cubs-at-point-defiance-healthy-and-adorable/27613921/