Medusa's Gaze and Vampire's Bite: The Science of Monsters by Matt Kaplan Read Free Book Online Page B

behind it? Like other animal-inspired monsters, it is worth considering whether a mutant of some sort was born that the ancients viewed as a monster.
    Animals can sometimes be born with the traits of other animals on their bodies. Horses, which normally have just one toe, can be born with multiple toes, dolphins can be born with legs, and humans can be born with tails. These mutations happen when very old genes, which have been inactive in an animal for years, for reasons not entirely understood suddenly become expressed instead of the genes that normally should. Called atavisms, these genetic mutations can create chimeric-looking organisms.
    But atavisms are not totally random in what they do. They do not simply grant a random trait. Humans are not born with wings and snakes are not born with fur. Instead, they produce traits that existed in the evolutionary past of that animal. Think about it: Human ancestors had tails, horse ancestors had multiple toes, dolphin ancestors had limbs. Odd as it is, there is a logic to the mutation.
    Yet Chimera does not show characteristics of lion ancestors mixed with those of a lion; it has characteristics of a goat and snake. This is not helpful. If the lion were the base animal that an atavism were taking place in, the lion could be born with a weasel-like face and shorter limbs because the evolutionary lineage that eventually led to lions contained a lot of weasel-like predators. But it would not be possible for a lion to be born with any snakelike traits because lions did not evolve from snakes or their relatives. The same is true of goats. Lions and goats are actually relatively closely related, but traits that are identifiably goatlike, like a goat head with horns, appear in the goat evolutionary lineage long after it breaks away from the evolutionary lineage leading to lions.
    Even if the evolutionary pathways were different and the lion’s ancestry did stem from a lineage that had given rise to goats and snakes, it is hard to imagine a mutant carrying all of these traitssurviving birth, let alone its first few months of life, with the sorts of deformities that would have been required for Chimera to have existed. For these reasons it is impossible for an animal looking like Chimera to have ever been born.
    Yet the basic ideas upon which Chimera is founded are not, on their own, totally ridiculous. Take, for example, Hesiod’s description of the beast having multiple heads. Animals can have two or more heads when twins or triplets develop abnormally in the womb.
    Under normal circumstances, an embryo forms from a sperm and an egg. But sometimes, shortly after fertilization, the cluster of cells destined to become the embryo spontaneously splits into two fully functional clusters of cells that go on to become two embryos. This results in identical twins. However, it is speculated that sometimes the two clusters of cells do not entirely break away from one another or that after breaking away they partially reconnect. The result, if the twins survive to birth, is conjoined twins.
    Among humans, such individuals’ lives can be medically challenging, as two brains are often forced to share vital organs like stomachs and hearts. For animals, survival is unlikely, since obtaining food requires finely tuned senses and considerable coordination. Two brains trying to control a single body makes coordination difficult, and animals with two heads are rarely seen surviving to adulthood in the wild. Even so, two-headed and even three-headed animals 17 can exist and might have inspired the creation of Chimera and other beastly blends like Hydra and Cerberus.
    The idea of having limbs that differ from one another in size and shape is not preposterous either. It is perfectly reasonable for an animal to be born, as the result of mutation, with hind limbs that are shorter than the forelimbs or are deformed and thus different-looking from the rest of the body. Again, these sorts of mutations would