Godzilla isn’t just a monster. He’s more than just an ancient Japanese movie god. He is an icon of science fiction, more responsible than any other creature for bringing kaiju films to the awareness of the world. Sure, Gamera is cool too, but the international cinematic community hasn’t quite embraced the giant turtle the way they have this giant lizard.
Since his debut in 1954, Godzilla has become a household name, and his appearance is legendary. Even with the hiccup that was Roland Emmerich’s 1998 attempt (resulting in a creature that is rejected as proper canon to the series), Godzilla has remained the king of the monsters, literally getting bigger and bigger every year. (Seriously, he’s now more than twice as tall as the original from 1954.)
These films sure are fun to watch, but when you see enough of them, you can’t help but wonder: Could a creature the size of Godzilla actually exist? Could we make our own?
The Answer: Sadly no
In Gareth Edwards’ Godzilla, the Big G’s main antagonists are two giant insect-like creatures called MUTO (Massive Unidentified Terrestrial Organisms). One is about as tall as Godzilla himself, but the other is a bit smaller. Still, they are massive in size. These creatures’ sizes and biology are explained by there being higher radiation levels in the prehistoric world. The concept of increased prehistoric radiation is a real thing, due to the fact that the original isotopes in the planet hadn’t decayed yet, greater solar activity created more cosmic radiation, and the atmosphere of the time did not filter out as much UV radiation from space. This resulted in a prehistoric radiation level of six-to-seven times as intense as we experience today.
However, these levels of radiation are not hundreds or thousands of times greater than what results from an exposed nuclear weapon or exposed nuclear waste. Even if Godzilla and his MUTO enemies were used to higher doses of background radiation, that which comes from their source of food in the movie – or more specifically from the bombs that were originally used to try and destroy them – could still deliver a lethal dose.
In short, the radiation they supposedly feed could would likely still kill them, if they were only evolutionarily adapted to simple prehistoric radiation. If they had adapted to absorb massive doses of radiation that only comes from concentrated nuclear material, the question remains where that actually came from in the prehistoric world? Conspiracy theorists might point to a cover-up of a prehistoric nuclear war (seriously… this is a real kook theory), but that’s even crazier than a kaiju attack in modern day.
What about their size?
In Godzilla, the MUTO are essentially giant bugs. While the film does not provide an anatomy lesson of these creatures, they exhibit most of the external characteristics of an arthropod, which includes a hard exoskeleton, and that would have been their downfall.
Arthropods simply can’t grow to such enormous size.
The largest arthropod ever to have existed on planet Earth was a massive sea scorpion that swam in the oceans of the Devonian period. It grew to lengths of up to 3.5 meters long, which is more than 11 feet. The largest arthropod ever to make its way on land was a six-foot-long millipede in the Permian period. Today, the largest land-dwelling arthropod is the coconut crab, which can grow to a meter long.
These are pretty terrifying creatures, but they are a far cry from the 100-meter-tall MUTO seen in Godzilla. There’s a reason for that: it’s called the square-cube law.
This law compares the surface area of an object with the volume of the object. Because area is a two-dimensional concept and volume is a three-dimensional one, they increase at different rates. So when a creature increases its surface area or height by a factor of two, it’s actually increasing its volume and weight by a factor of three. In short, the taller something gets, its weight increases even more. This is why a six-foot-tall man weighs a lot more than a three-foot-tall child.
The square-cube law prohibits arthropods from growing much larger than a human because their internal muscles can’t move their exponentially heavier arms and legs. Because exoskeletons are moved by muscles attached to the inside of the skeletons, the muscles would simply snap under the pressure. So this means movies like Tarantula and Them! are just as much nonsense as Godzilla.
But Godzilla isn’t an arthropod
No, he’s not. Unfortunately (or rather, fortunately for the survival of coastal cities), the square-cube rule still applies to animals with an internal skeleton. As they grew larger and heavier, mammals and dinosaurs developed columnar legs to support their massive weights. This results in a slower moving animal, but there is still a limit to their size.
The biggest group of dinosaurs to ever walk the planet were the sauropods, and the largest sauropod was the Argentinosaurus, which maxed out at 120-feet long from nose to tail and weighing about 100 tons. Scientists believe that was close to the size and weight limit of land animals.
Even the smallest Godzilla, as seen in the original film, was more than 160 feet tall, which was likely more than twice as long as the Argentinosaurus from nose to tail. A conservative estimate of his weight would be 20,000 tons. This is, of course, nothing to the 100-meter tall creature in the 2014 film, which is 400 feet from nose to tail and likely weighing 60,000 tons. A creature that size would collapse under its own weight. Even if it managed to walk onto land, if it were to fall over, 60,000 tons of force crashing to the ground from a height of 100 meters would shatter its skeleton.
Considering that Godzilla gets bigger over the years, most likely in response to the size of the skyscrapers being larger in 2014 San Francisco compared to the relatively shorter buildings in 1954 Tokyo, there’s little chance of seeing this trend stop. However, you can’t say it’s even remotely scientifically possible.
Sadly, that means movies like Pacific Rim are utter fiction as well.
However all is not lost. Godzilla is known for not just stomping on cities, but for his home in the sea. He’s an amphibious creature that can swim great distances, and this might be more realistic than some might think. The square-cube law of size still applies to aquatic animals, but they benefit from the buoyancy of water. When something is submerged in water, the water supports it with the weight of the displaced water.
Remember how much larger the prehistoric sea scorpion was than the six-foot-long land-dwelling millipede? In an aquatic environment, creatures can grow much larger than they can on land. In fact, the largest creature to ever live on out planet that we know of is the blue whale, which reaches lengths of 100 feet and can weigh up to 200 tons. This is still a far cry from Godzilla’s massive size, but it’s a start.
Still, if Godzilla isn’t stomping down city blocks and knocking over skyscrapers, it’s really not worth it.