The Biology of Godzilla

I've noticed some confusion about what kind of animal Godzilla’s species is within the context of the new origin story. Is he an amphibian, a reptile, or more specifically, a dinosaur? Based on what I’ve seen thus far, if he were a real creature, he would likely be classified as an archosaur, a group that includes pterosaurs, dinosaurs (which also includes birds), and crocodiles. Godzilla has an erect gait, meaning his legs are placed directly beneath his body, not splayed outwards like non-archosaurian reptiles. His hind feet each have four toes which is typical of archosaurs. His hands have four fingers showing asymmetrical digit reduction similar to what occurred in early theropod dinosaurs. His head is very reptilian with the jaw muscles being visible when he opens his mouth; the jaw muscles are also covered with a flexible, scaleless, cheek-like skin. He of course has a row of bony dorsal scutes similar to those of many crocs and dinosaurs. Godzilla’s underbelly is covered with plate-like armor scutes similar to those of crocs and some dinosaurs.

But what about the gills? Godzilla does appear to have gills located on the lateral sides of his neck, but reptiles do not possess gills. Considering all the traits Godzilla shares with reptiles, specifically archosaurs, it would be more likely that the gills evolved secondarily—meaning they were completely lost then later re-evolved—rather than that a amphibian lineage independently evolved remarkably archosaurian/dinosaur traits. The gills could be highly modified, vascular scutes that can absorb gases dissolved in water. Of course, The presence of gills on Godzilla are far less problematic than the structural adaptations that allow such an enormous creature to stand without immediately collapsing into a pile of meat. Godzilla’s connective tissues would need to be composed of materials vastly stronger than collagen, elastin, and calcium carbonate. Instead of calcium, his bones would need to be composed of some kind of extremely strong natural alloy, and his other connective tissues would need to be made of something on par with nanotubes or graphene, the former of which can apparently be biosynthesized by bacteria. His muscular tissue would need to be composed of polymers that have much greater tensile strength and contractile force than normal muscle. Some polymers such as nylon are a 100 times stronger than normal muscle, so perhaps it could be something along those lines. The same adaptations that allow Godzilla’s species to grow so large would probably also afford him with near invulnerability to conventional weapons.

The most implausible aspect of the godzilla species is their apparent ability to expel ionizing radiation. Considering that some of Godzilla's connective tissues would have to be made up of some carbon allotrope, perhaps his particle beam breath could be handwaved by those same connective tissues being electrically conductive or magnetic, allowing him to direct a beam of charged particles out of his throat. If he were real, a blast from his breath would likely give nearly everyone in the vicinity radiation poisoning due to scattering of high-energy particles. Godzilla would have a very strange metabolism. If Godzilla is radiotrophic, in a similar way to how plants are phototrophic, then ionizing radiation could drive chemical reactions that convert some compound into his body into food; this means that Godzilla would make sugars and amino acids from inorganic compounds such as CO2 and water. Consequently he would not need to eat as much as a normal reptile, as much of his food could be produced via radiosynthesis.

Why do his dorsal spines glow when he emits his radiation beam? The dorsal spines themselves could contain radioactive isotopes such as uranium and plutonium. It would make sense that the dorsal plates would be external, tall and flat, as this would dissipate waste heat produced from radioactive decay. The dorsal plates could be extensions of his vertebrate which could be pneumatic (hollow) and contain a series of sacs. When the rate of fission is suddenly increased, the plates might emit light and the resultant alpha particles (helium ions) or plasma could be directed through sacs or tubes that run the length of the neck and terminate by opening into throat. The sacs and tubes would need to be enormously strong and heat resistant, on par with the hypothetical engines of a starship, as well as conductive like a particle accelerator. When Godzilla "eats" something like a nuclear submarine, he may be consuming fissile material that is later stored within his dorsal plates.

On a final note, I’m aware this is all very far-fetched and perhaps a bit silly, but it was a fun thought experiment that attempts to extend Gareth Edwards attempt at realism with an otherwise completely absurd premise.