Ever since its introduction in the Second Generation, the concept of Pokémon breeding, while greatly appreciated, has spawned a plethora of questions, including, but by no means limited to – how can completely different species successfully copulate? How can they produce fertile offspring that are functional and not riddled with genetic malfunctions? Why is a tiny little cat able to have sex with literally the largest Pokémon known to us thus far? Perhaps one of the largest contributors to this pool of questions is Kangaskhan, a species that is 100% female and is born already equipped with a baby in pouch.
There is much to be said about the Parental Pokémon, aptly named since it literally enters the world a mother. It comes as no surprise that its design is inspired by the kangaroo, yet there is so much more to learn from her. Indeed, Kangaskhan is more than a magical marsupial, she is a shining example of the remarkable process that we in our world know as parthenogenesis.
A World Without Men
Time to have a talk. The Talk to be precise.
Excuse me if my heteronormative bias shows here but typically speaking, a man will encounter a woman and either through coercion or brute force insert his penis into her vagina and deposit his half of the reproductive materials via ejaculation. His materials, commonly known as sperm, enter the vagina, with a few lucky individuals making it past the cervix to – if this woman he has taken is ovulating – join with a nice plump egg waiting to be fertilized. The first sperm to penetrate its outer membrane wins the prize of fusing with the ovum to form a zygote and nine months later a baby is born.
We call this process sexual reproduction and it requires the existence of two sexes at minimum (though there can be more in some cases) since its main selling point is the promotion of diversity. Like a college admissions department, diversity is the name of the game when it comes to genes. More variation means more unique individuals with traits that may or may not prove advantageous in life. However, sexual reproduction is not the only way to make a baby.
If diversity is not really your interest and you’re just looking to pass on your legacy without the energy and drama that comes with sex, asexual reproduction may just be what you’re looking for.
In asexual reproduction, no new genetic material is added. The next generation is genetically identical to that before it with no variations other than the random mutations that still occur during DNA replication. Naturally, this leads to severe lack of diversity with very few, if any, differences between individuals, but has the benefit of not needing to expend energy in courtship and actual mating. Additionally, asexual reproduction only requires one sex.
There are many forms of asexual reproduction – budding, binary fission, clonal fragmentation. But perhaps the most interesting form is parthenogenesis, essentially virgin birth. Offspring of parthenogenic organism develop from unfertilized eggs. Most organism that use parthenogenesis do have two sexes, as well as the ability to reproduce sexually, and often fall back to it when conditions become adverse and the diversity is needed1. However, there are some species, such as Kangaskhan, that have abandoned the entire male line in favor of an all-female feminist utopia.
Take for example Aspidoscelis uniparens, the whiptail lizard, a species that contains no genetic males and reproduces completely through parthenogenesis. Oddly enough however, the females of this species do engage in mating rituals similar to that if they were reproducing sexually which enhances ovulation. Furthermore, despite being asexual, whiptails have managed to find a way to preserve some degree of genetic diversity through combining sister chromosomes instead of homologous chromosomes2.
It appears that Kangaskhan has taken a similar evolutionary path to the whiptail lizard. Being a male-free species can have its benefits especially for a creature as devoted to its young as Kangaskhan. The PokéDex entry in Emerald appropriately states, “If you come across a young Kangaskhan playing by itself, never try to catch it. The baby’s parent is sure to be in the area, and it will become violently enraged.” With sexual reproduction comes competition between not only the sexes but between competing males, each vying for a womb to continue his genetic legacy, and children are often the first casualties in this war, as it is not rare for a male to kill the offspring of another male so to ensure his are the only ones that end up surviving. With Kangaskhan’s identity wrapped up in protecting its baby, a sexual society would prove troublesome, male Kangaskhan mutilating babies while forcing fertile females into copulation. A better situation could be created without the presence of males, one in which the young are protected and mothers rested easily without the threat of a male high on testosterone killing her child.
Parental Bond: More than an Ability
Perhaps more than any other class of animals, mammals have mastered the art of motherhood. Few other organisms take on the burden of reproduction to the extent that mammals do. From the moment of conception, the mammalian mother is dealt with the burden of having to carry and support what essentially boils down to a temporary parasite that drains off its energy over whatever period of gestation it takes. Then after the offspring has been born they are still tasked with the job of providing additional nourishment through a unique little gland named mammary (yes, that’s where mammal comes from), in doing so providing them with invaluable proteins, antibodies, and other goodies that’ll help them later in life.
But for marsupials in particular, motherhood comes with some additional stakes. A joey (baby kangaroo) is born early in its development, with a gestation of only 30-36 days. The pink gooey bundle of joy resembles its distant cousin the gummy bear more than a kangaroo at this stage in its life, being no larger than a lima bean. Being basically a living fetus, the joey is especially vulnerable in these first months. However, it quickly climbs to the pouch with its barely formed forelimbs and latches on to its mother’s teat where it will reside for the next nine months, feeding on its mother’s milk from the safety of the pouch.
One can imagine that it can get crowded quickly in a pouch. Thankfully, kangaroos have evolved a unique adaptation called diapause, in which a mother essentially freezes the development of an embryo while her pouch is occupied. Once the joey is old enough to leave the pouch for good, the embryo is allowed to continue its growth, thus allowing the kangaroo mother to allot all of her attention to the primary offspring on hand.
This being considered, I find it interesting that in Kangaskhan’s Mega Evolution, the vigilant mother finally lets her current joey from the safety of her pouch to fight side by side with her, herself unchanged by the actual Mega Evolution but her young larger and more plated, starting to resemble its adult form. Perhaps this particular event is more than just temporary battle effect, but the release of Kangaskhan’s current joey and the unpausing of diapause, in which the joey that resides in her pouch post-Mega Evolution is not the same joey that was in battle but the newly developed embryo grown into a joey after months of diapause.
Lutes, A. A., Neaves, W.B., Baumann, D. P., Wiegraebe, W., Baumann, P. (2010). Sister chromosome pairing maintains heteroozygosity in parthenogenetic lizards. nature.com.