Section Two: General Biology

Scientific Classification of Pikachu

Kingdom: Pokemon
Phylum: Chordata
Class: Mammalia
Order: Rodentia
Family: Muridae
Genus: Mus
Species: Chu (includes pichu and raichu)
Subspecies: Pikachu

[Other terminology: a male is called a buck and a female is called a doe. Pichu are referred to as pups.]

General Description

Pikachu are small rodent-like Pokemon with yellow, black, and brown fur. They have long pointed ears with black tips, large eyes with a brown iris, one red circle on each cheek, and a small mouth. Their bodies are short and chubby and covered in yellow fur except for their back which has two brown stripes in the middle. They have two arms with five fingers on each paw. Their back paws have three toes and are long. And they have long lightning-shaped tails.

Anatomy Break Down

I will now break down each part of the pikachu starting from the ears and ending with the tail.

Ears

The classic pikachu ear. So recognizable are the ears that they could be considered the defining feature, other than maybe the tail, of the pikachu. But the long, slender, black-tipped, points are more than just for looks. For a pikachu, the ears are a way to express emotion, tune into electrical frequencies, and, of course, hear.

Pikachu ears can display a whole host of emotions. When down, it can mean they are sad, afraid, ashamed, or feeling ill. When perked up, it can mean they are excited, attentive, interested, or on alert. When one is lowered and the other raised, it can mean they are concerned, confused, or feeling mischievous. When in a neutral position, it can mean they are feeling healthy, calm, or just relaxed.

The most fascinating function of the ears is the ability to tune into electrical frequencies. Try this with your pikachu sometime. If you have an old-school T.V., have your pikachu sit on top of it. Then set it to the station of your choice, and adjust your pika’s ears just like you would an antenna. It should work just the same if not better. Your pikachu can become a set of near-literal bunny ears! Of course, your pikachu will not tolerate being used like this for long so enjoy it while you can. But this trick isn’t just for getting a clearer picture of your favorite soap opera. To a pikachu, it is a way of communicating with each other over a large distance. Pikachu are always sending out faint frequencies of their own. Each pikachu has their own unique frequency like humans have thumbprints. To study pikachu, we use this frequency to identify an individual pikachu easily. And pikachu can use this to find lost members. If a pikachu is lost, they can boost their signal temporarily by running current through the ears. And if the pikachu looking for them knows their frequency, they can adjust their ears to the lost pikachu’s signal to locate them. This only works if the lost pikachu has electricity and if others are actively looking for them. A rare occurrence, but proves to be very useful when it is needed.

Eyes

Pikachu have two large brown eyes. The whites of the eyes are seldom visible. Pikachu are capable of expressing emotion through them similar to a human and can even cry to display pain or grief. Pikachu can also see in full color, like humans, and can even perceive infrared if they have electricity. They can use a small amount of electricity to heighten their sight to see otherwise dark areas or at night. This does eat up their electricity usage and typically will only use it if need be.

Cheeks

Another iconic feature of the pikachu, the cheeks have one red circle on each cheek. Under these red circles is where the pikachu makes and stores its electricity. The pikachu has a similar electricity-making organ found in many Electric-type Pokemon. The organ is a long tube made of special highly conductive cells. The tube is wrapped in a spiral in the same manner as a human-made generator. The organ acts as a conductor and rotates when fed organic energy. Pikachu have a natural magnetic field and when the organ rotates it produces an electric current. This current is then discharged into the cheeks for storage.

The red circles are not cheeks but are actually another organ composed of cells called electroplaques and acts a lot like a human battery. This organ is also found in most Electric Pokemon but is usually hidden inside the body and is in one location, not two. But pikachu display them outwards which has its advantages and disadvantages. It allows the pikachu a more powerful, direct shock for its relative size, but it also can be accidentally discharged if the pikachu is frightened or the cheek comes into contact with a conductor like copper. Pichu, in particular, seem to have the most trouble with accidental discharge.

If the pikachu wishes to discharge the electricity, all it has to do is squeeze its cheeks; if lightly, electricity will flow through their body without expending much energy. This can be used to warn off predators or power some of the pikachu’s special abilities - like the previously mentioned infrared vision. If squeezed hard, it will send out a strong shock that can be directed at a foe. Trainers in the Pokemon League call this shock a "Thundershock." If you own a pikachu, you've probably experienced this shock a few times and can attest to the pain. In larger creatures, Thundershock can cause extreme discomfort and slight paralysis, but in smaller creatures, especially ones weak against Electric, can kill in just one shock. Even larger creatures can be killed by Thundershock if electrocuted multiple times within a few minutes. A wild pikachu will typically have between three and five shocks stored if fully rested and fed. Domesticated pikachu are known to store more electricity for a reason we will get into in the diet section.

The electricity in the cheeks is also capable of returning energy to the pikachu if need be. If the pikachu is injured, sick, tired, hungry, etc., the electricity stored will be discharged back into the body where it is most needed. While useful in healing injuries and running long distances without stopping, it does have its drawbacks; if a pikachu is injured by a predator, then the electricity that was being stored in the cheeks is now gone, leaving the pikachu defenseless. The most extreme case of this is when a pikachu’s jugular vein is severed. Upon this type of blow, the pikachu is immediately sapped of all energy and is unable to shock even once. Unfortunate because most predators will go straight for the neck. But if the predator misses the jugular the pikachu will shock instinctually upon intense pain and give at least one good shock, reminding the predator why they should be more careful when hunting pikachu. Because of this, most smaller hunters, like the vulpix, who would normally prey upon pikachu, avoid hunting pikachu unless they feel the pikachu is exhausted or they pack hunt the pikachu - which in the case of vulpix, is rare unless it is during the breeding season.

Mouth and nose

The nose is small and black. A slight snout can be seen from the side but is much more retracted than in other rodents. It has no special traits. Compared to other rodents, the sense of smell is weak. But a pikachu’s sense of smell is still fourfold stronger than a human’s.

The mouth of the pikachu is small but is capable of displaying a range of emotions, just like in humans. Inside the mouth, like with all rodents, are sets of incisors teeth - two on the top row and two on the bottom. These incisors are ever-growing but are rarely seen, even with the mouth of the pikachu open. This is due to the pikachu keeping them well worn with a gnawing stone - a stone used to supplement a pikachu’s dietary need for heavy metals. [This is why, unlike other rodent Pokemon, many owners find their pikachu doesn’t typically chew on furniture or other such items. Although, if you look in your pikachu’s mouth right now, you may find that battery that went missing from your remote a week ago.]

Body

The torso of a pikachu is small, only about eight inches tall and chubby - though, the body of the pikachu is not as chubby as it once was. The chubby bodies help them survive during the harsh Viridian winter months. On their back are two brown stripes. These stripes are used to make the pikachu appear larger to predators attacking from the back and to disorientate predators in a chase.

The body, and most of the pikachu, is covered in yellow fur. This yellow fur has specialized oils that cling to the fur follicles. This oil is slightly acidic and allows for easier travel for electricity.

Limbs

The pikachu has four limbs, two arms, and two legs. The arms are short and stubby. At the end of the arms are paws. These paws are not like normal rodent paws and are instead more like that of primates. The paws have five fingers, one of which acts a lot like a thumb, although it isn’t developed enough to be considered one yet. Still, pikachu can hold objects other rodents would not be able to. Pikachu can also toss objects - although pikachu will typically use their tails as a bat if they want to launch an object a long way. The paw is great for climbing as well. Pikachu have even picked up human hand gestures like the peace sign or a simple wave. And I’ve seen some stray pikachu in cities that have picked up ruder hand gestures. Inside the wild tribe, only the simple wave is used. It is unclear whether the wave was always a part of the pikachu’s culture, or if even in the depths of the forest, human influence has made this a custom.

The legs of the pikachu are mostly hidden within the chubby body. The part visible is not the leg but the back paw. The back paw is long and has three toes. This long paw gives the pikachu leverage when running and allows them greater speed; it also allows the pikachu the ability to stand on its hind legs. The pikachu has a double articulated hip structure that allows for the speed of a rodent when on all fours, and the ability to walk, albeit awkwardly, on their hind legs.

Tail

Last, but certainly not least, is the tail. Of all the features, the tail is the most fascinating. It is long and in a lightning shape. But other than being iconic, it is used for balance, greetings, conveying emotions, courting, electricity production, transfer energy, and produce its own magnetic field.

In social situations, the tail is used as a greeting. Two friendly pikachu will touch tails and sparks will jump between the tails and their fur will stand on end. This is equivalent to a human handshake. It is also vital in courting, but we will go into greater detail when we come to that section. The tail can also convey emotion: if lowered, it can mean they are sad, scared, or nervous; if raised it can mean they are angry, defensive, or aggressive. Many experienced trainers will watch the tail of a pikachu to see when it is okay to approach. If you approach a pikachu with its tail raised, you may be in for a nasty shock.

Pikachu will also touch tails to transfer energy to others who are low on their electricity. It can be done cheek-to-cheek but is usually done with the tail. This proves very useful when under attack from predators. Even just two pikachu can hold off larger predators for this very reason. It can also be used to cure sick or injured pikachu. Like mentioned before, pikachu can heal themselves with electricity. And when given electricity from others, they can stave off infection and serious illnesses. Although, this does have its limitations.

But it is the tail's natural electromagnetic field that proves the most significant benefit to the pikachu. Try this with your pikachu; take iron filings and spread them on a flat surface, like a table. Then wave your pika's tail over the filings, and you will find, the filings will align with your pikachu's magnetic field. The tail is made of cells similar in composition to magnets. This property can power a lot of a pikachu's natural abilities.

Pikachu can change the rigidity of their tail by sending a current through it. This aligns the cells into a hard structure and can be used to knock, toss, or even attack. If a piece of fruit is in a hard-to-reach spot, the pikachu may jump up and knock the fruit with the tail. If you've ever thrown a Pokeball at your pikachu and they do not want to go in, you may find it being batted like a baseball right back at you. And pikachu with the help of T.M. can learn the move Iron Tail, which aligns the cells in the tail so much so the tail can be used to attack foes dealing serious damage.

A pikachu's tail also has its own polarity. Females have south polarity at the tip, and males have north. This may explain the visual differences in the tail. But pikachu can freely change the polarity if they wish; doing so does expend a small amount of energy. This feature can be used for navigation. A lost or disoriented pikachu can raise its tail in the air and let it freely rotate to discover magnetic north. If you ever get lost hiking with your pikachu, that ability might just save your life. If a pikachu becomes excited or angry, this magnetic field can damage electronics. So be careful with your phone's location or turn it off if you intend to handle an excitable or untrained pikachu.

Briefly: Pichu's Biology

Pichu, considering they are the former evolution, are very similar to a pikachu biologically. The main difference is their tails. A pichu’s tail’s magnetic field is weak and erratic and causes all the troubles associated with pichu. First, it makes it hard to generate electricity. The weaker the field, the longer it takes to make the required energy to charge the cheeks. Pichu only have about one or two shocks in them, and it takes days to charge them. And these shocks do not pack as much punch as a pikachu's. That isn’t to say a shock from a pichu doesn’t hurt; ask anyone who has experienced a pichu shock, and they will be sure to tell you.

Second, this weakness in the magnetic field causes accidental discharge or sometimes the inability to discharge at all. If a pichu is scared or amused, it may discharge. This makes pichu easy to hunt. A predator simply has to threaten a pichu with its very presence, and the frightened pichu may discharge out of range of the predator, making them easy pickings. If the weather conditions are dry, the pichu may discharge just from the low humidity; if the weather is too humid, they may not be able to discharge at all. And when one pichu discharges, other pichu nearby, especially on dry days, may discharge as well causing a chain reaction. When this happens in large groups of pichu, we researchers call it a mass pichu discharge event or MPD event. It is quite the sight to behold but has never been captured on film for it destroys any electronic equipment in the area. The MPD event is followed by a bunch of crying pichu and their adult forms trying to comfort them. Trust me, it is very cute.

And third, the fluctuating erratic magnetic field reflects some electricity back on the pichu itself. This will hurt the pichu mildly and usually result in them crying. All these factors make pichu very vulnerable and reliant on pikachu for protection.

The last major difference between pichu and pikachu is the pichu’s inability to reproduce. Pokemon breeders call Pokemon like this “Baby Pokemon.” It is an apt name, for pichu are prepubescent and don’t become pubescent until they evolve into pikachu. This is very rare in the Pokemon Kingdom. Most Pokemon become sexually mature within their first evolution.

Internal Biology

Brain

The pikachu's brain, unlike other rodents, is creased like a human's. These creases allow for more surface area, increasing the number of synapses. This may be why pikachu are so intelligent as compared to other rodents. Also, the pikachu can increase the firings of synapses when using electricity. This allows the pikachu to see in slow motion if the need arises like if they are under attack. The brain-to-body mass index of a pikachu is large as well, putting pikachu up there with more intelligent avian and primate Pokemon.

Digestive Tract and Diet

The pikachu has a standard rodent digestive tract which is similar to a human’s. As mentioned in the mouth section, pikachu have ever-growing incisors. They use these incisors to gnaw on hard food like nuts. Pikachu’s diet requires large amounts of fruits high in sugar, mainly berries and tree fruits, to keep their cheeks powered. Underripe fruit is sometimes rubbed on the cheek of the pikachu to soften the fruit with electricity. They can also supplement their diet with root vegetables, like carrots or wild onions, but prefer berries overall. Hard nut foods, like chestnuts and walnuts, are collected throughout the warm months and saved up for the winter - and are usually only eaten then.

Pikachu do have the ability to be omnivores. There is nothing genetically holding them back from eating meat; though pikachu don’t often eat meat. It seems this is due to a religious belief within the tribe. To what this religious belief means exactly to pikachu, I am unsure, but any pikachu caught eating meat is exiled immediately. It doesn’t make much sense. Pikachu could be capable pack hunters and would very easily hunt Pokemon like pidgey or goldeen. A high protein diet would be beneficial to pikachu electricity production and brain function. If pikachu started eating meat widely, we could see a rapid change in evolution. Something akin to early sapien development. With the ever-harshening environment of the Viridian Forest, it is only a matter of time, in my opinion, that pikachu do start eating meat. And how that will affect the forest’s ecosystem is unknown. Even now, there is a small group of pikachu within the tribe that do hunt meat under the cover of darkness. How long until this becomes commonplace?

Another important part of the pikachu’s diet is a gnawing stone. Pikachu’s specialized electrical cells require large amounts of heavy metals to function properly. Luckily for pikachu, the forest is host to bountiful amounts of galena. Galena is a mineral ore with high amounts of lead. So much galena is within the forest that for years Viridian City's main source of employment was a lead mining plant; though, the plant was closed a couple decades ago. When digging, pikachu come across chunks of galena and place it in their mouths. They will keep it in their cheek pouch and gnaw on it when they feel the need. Just one small stone can last a pikachu months.

[note: many inexperienced pikachu owners will complain of their pikachu being too aggressive, discharging often, smelling of sulfur, or destroying electronics. These owners often seek obedience training when the problem is dietary. Pikachu need gnawing stones like we need salt. In lieu of galena, pikachu will use other heavy metals to gnaw on; and, what would a pikachu chew on inside a human house for these heavy metals? Why, batteries of course! Batteries contain lithium along with other heavy metals. These metals are in much higher concentration than in galena ore. If your pikachu has been eating batteries, don’t worry; consuming batteries is not harmful to pikachu, but it does result in extremely overactive electrical organs. This will cause pikachu to have overcharged cheeks and will make your pikachu have all the ailments listed above. Many trainers in the Pokemon League will intentionally feed their pikachu batteries for better performance in battle. But if you just want a pikachu to snuggle up to, then having them chew on batteries is a nightmare. Instead, try this; buy a pound of galena gravel from online or from your local Pokemart, then place it in a bowl next to your pikachu’s food bowl. Galena is fairly cheap and a pound should last you a couple of years. Pikachu prefer galena over batteries and will use it as a gnawing stone. This will have a few good effects; first, your pikachu will be friendly and social; second, you will get shocked less and have to replace your phone less often; and third, you won't have to buy as many batteries for your remote.

And a note to battle trainers: instead of feeding your pika batteries, invest in a Light Ball. Light Balls are gnawing stones scientifically engineered specifically for pikachu to have the perfect blend of heavy metal nutrients. Light Balls are expensive but worth the investment. They greatly boost the stats of your pikachu, making them more competitive within their weight class. Plus, your pikachu won’t get the sulfur smell emanating from their cheeks or the aggression outside of battle. But be warned; Light Balls are considered a held item by the Pokemon League and will use up your pika’s item slot. Using another held item in battle will disqualify you instantly.]

Reproductive Biology

Female pikachu have a standard mammalian womb with egg receptor nodes for both Field semen and Fairy pollen, also known as pixie dust. The main difference in the womb as compared to other rodents is the womb only has one cavity instead of two. This is because females only produce one large egg at a time. Rattata, for example, will have five to six eggs in one birth.

Like all Field Pokemon, female pikachu experience a heat cycle. Female pikachu have a unique ovulation cycle than most others. It starts in early spring and will last until fall, or until she is bred successfully. During that time, she will give off strong pheromones through her urine; the exact same pheromones found in other Field group Pokemon. These pheromones let males know she is in heat and ready to breed. She will also give off an aura. Auras are the equivalent of pheromones to a Fairy group Pokemon. How this aura manifests itself to Fairy Egg-group male Pokemon is unclear - though, some humans claim to smell a sweet scent emanating from ovulating Fairy group Pokemon. Pikachu in the wild only have one egg a year unless the egg is still-born or the pichu dies before the start of fall - in which case, she will enter her heat cycle again.

[note: Fairy pollen, or pixie dust, is used as a natural zero-calorie sweetener and is commonly added to food dishes and drinks. (Which, if you think about it, is kinda gross, but to each their own.) Many people keep jars of pixie dust in their pantry to cook with. But be careful! Pixie dust has an intoxicating effect on ovulating Fairy females. If you own a female pikachu that has not been spayed and is currently ovulating, she will be attracted to the pollen and seek to stimulate herself with the dust. Keep that stuff locked away tight, or better yet, have her spayed. Many careless owners have returned home to a broken jar, a house covered in pink dust, and a pikachu looking quite pleased with herself; then to find out a few days later, the mess was only the beginning of their problems.]

Upon successful insemination, the female will know in a matter of hours, if not less time, if she is now with egg. Though, visible signs of her pregnancy will not occur until day three or four. Gestation of the egg will last three to four weeks. Pikachu's eggs are large compared to their body mass and birth is painful to them. After laying the egg, the female will spend most of her time, curled around the egg, providing the egg warmth. It will be an additional three to four weeks until the egg is hatched. This conception-to-hatching cycle is about twice as long as other rodent’s cycles. The offspring will always be a pichu no matter what Pokemon impregnated her.

Females also have four mammary glands for feeding pichu. These glands are hidden under the fur and are typically not visible even if breastfeeding. Why four when pikachu usually have at most two nursing pichu at a time? My only guess is a genetic holdover from a time when they were more like their distant cousin the rattata.

Males have a standard mammalian rodent variant penis and testicles. The penis is tapered and sheathed and only reveals itself if the pikachu is aroused. The testicles are kept in a pouch between the legs and produce both Field semen and a liquid variety of Fairy pollen. Both are mixed together and ejected through the urethra upon orgasm. The semen is capable of impregnating any female Pokemon within Field or Fairy egg groups. Although, a pichu offspring only occurs if he impregnates a female pikachu or a ditto. Otherwise, the offspring will be the lowest evolution of the female's species.


Sexual Dimorphism

Pikachu, like quite a few Pokemon, do have biological differences between the sexes. Most trainers can readily tell you the sex of a pikachu by one look at the ends of their tail: males have a flat edge, while the females have a dip, making the end of the tail look almost heart-shaped. But the difference goes deeper than that.

Males tend to be physically larger;
size range: 1’2”-1’6”
weight: 12-16lbs

While females tend to be smaller;
size range: 1’0”-1’4”
Weight: 10-14lbs

This size difference allows males an edge in physical attack and makes them more durable. This size difference may have arisen in recent generations due to the males defending the tribe from predators. [note: the size difference is not as substantial in domesticated pikachu.]

But in terms of electrical output, the difference is nominal, with a potential slight edge to the females. The other differences are small: males’ coats have a shade brighter yellow, the magnetic polarity of their tails are opposites, and the circumference of a pikachu’s cheeks are slightly larger on a female. Also, the average lifespan of a pikachu that stays in the tribe is similar between the sexes: 9-12 years [Don’t worry about your chu! Wild pikachu have a much shorter lifespan than domesticated pikachu due to the harsh environment, lack of quality food, and nonexistent healthcare. A well-cared-for pika pet typically will live about twice as long as the wild pikachu.]

Reproductive Strategy

In the field of Pokemon research, there are two kinds of reproductive strategies found in pokemon, r-selection and K-selection. These two types are on a continuum. With r-selection, the Pokemon in question will birth many children but not parent any of them. Most of these young will die, but the hope is to use their numbers to have a statistically high chance of reproductive success. Think of the butterfree: a female butterfree will lay over five hundred eggs over the forest. They descend on silk strings and land in trees. Once she lays them she doesn't attend to them ever again. Of those five hundred eggs, only five percent will hatch and then survive as a caterpie to evolve into a metapod. And of that five percent, only ten percent of metapod will survive to become butterfree. If you do the math, that means of the five-hundred eggs, only two or three will live to reproduce as butterfree. The benefit of r-selection is the adult does not have to spend any extra energy or time raising their young. The downside, if you are born an r-selection type creature, the likelihood that you will meet a gruesome end before growing up is almost guaranteed.

On the other end is K-selection. K-selection does the opposite of r; instead of having many young, the creature in question will only have a few but spend much more time raising and teaching their young. Think humans: we have only a few children in our lifetime and have to watch over them until they are much older. Pubescence in humans doesn’t even occur until eleven or twelve years. And in modern times, some parents take care of their children until they are mid-twenties or later. The benefit of K-selection is your children aren’t dying all the time and this kind of selection seems necessary for more intelligent creatures. The downside, the parents have to invest huge amounts of time and energy into keeping their young alive, and since they have less of them, losing a child is devastating, both in a reproductive sense and a grief sense.

Pokemon can also have a blend of these two selection strategies. Think vulpix: vulpix have two kits a season and raise them for six months, then the parents will kick them from their den. Of the young vulpix born, over half will die before reaching next spring; much better odds than a caterpie, but not near as good a chance as a human child.

And what of pikachu? Let’s compare them to their distant relatives, the rattata. A female rattata will have five or six pups in a litter. She will raise them for a month then kick them from her den. A rattata pup only needs to live six months to reach sexual maturity but of all rattata born, only one out of five will survive to reproduce. A clear-cut example of r-selection.

But a female pikachu will have one pichu a year. She will raise them for up to two years until they evolve into a pikachu and still help train them for an additional year and be involved in the raising of her children's young. Contrasting this to rattata, of all pichu born, only one-out-of-five will NOT survive to become of reproduction age. A clear-cut example of K-selection.

To support such a reproductive strategy, pikachu culture needs rigid family structures, complex hierarchy, and a strong sense of morality. In terms of the percent of life spent as a child, pichu only biological rivals are humans. This may be why humans and pikachu get along so well; they share so much in common. It can be said, this K-selection is the basis for all pikachu life in a tribe and leads nicely into our next section.