The Godzilla franchise is more than 30 films that have raised the famous kaijū of the same name to the rank oficonicon Japanese pop culture. An institution which has seen its main character evolve and grow over the years. Literally. At its beginnings, in 1954, this funny dinosaur remained modest, with a size of (still) 50 meters high.
More than sixty years later, in 2017, he revealed himself in Godzilla: Planet of the Monsters and dominated the planet from a height of 317 meters, looking (almost) at the Eiffel Tower in the eyeseyes. And, recently, he is fighting alongside another giant of the big screen in Godzilla x King Kong: The New Empire. Two matadors never seen in the wild… but why? Is there a size limit for animals? The answer is yes, but it is less obvious than it seems.
Godzilla x Kong: The New Kingdom Trailer. © WB, YouTube
In the grip of physics and math
One of the first factors to take into account, for all living beings, is gravity. Without us realizing it, we – and all other land animals – must constantly fight against this force to move. And if we don’t notice it, well, it’s because we’re not very tall.
At more than 300 meters high, our massmass increase. It increases a lot. So much so that the effort we would have to make to move would be far too great compared to our strength. Furthermore, we should face a problem of difference in pressurepressure : our upper body would be subject to a different atmospheric pressure than our lower body. Finally, our limbs should be strong enough to support the weight of the body without fracturing.
All this leads us directly to our second factor: that of the mathematical law of the square cube. Stay with us, it’s not very complicated, I promise. This law formalizes the fact that as the linear size of an object (such as the length of its side) increases, its volume increases much faster than its surface area.
A law that has important implications for living things because it affects their ability to exchange gasgas with their environment and regulate their body temperature. For example, a larger animal will have a relatively smaller proportion of its surface area in contact with theairairwhich will make it more difficult to exchange heatheat and gas.
Evolution of Godzilla. © FilmCore, YouTube
But, not everyone is equal in height limits. Our physiology is decisive. For example, mammals are limited by their metabolismmetabolism warm-blooded. Unlike cold-blooded reptiles, which can be content withenergyenergy solar to maintain their body temperaturebody temperaturemammals must expend a lot of energy to regulate their internal temperature.
However, this energy, drawn from the environment (food for example), is also used for growth, which stops when the majority of the energy gained is spent entirely on operating the metabolism, thus imitating the maximum size of mammals. . If you dreamed of meeting King Kong, it’s gone.
And what about Godzilla? Theoretically, the Japanese monster is a kind of dinosaur and therefore part of the reptile family. They depend on their environment to regulate their body temperature. This adaptation allows them to conserve energy that would otherwise be spent maintaining a constant body temperature, giving them an evolutionary advantage in mattermatter of growth.
This is how dinosaurs reached colossal sizes, far exceeding most of today’s land mammals. Their cold-blooded metabolism allowed them to conserve more energy for growth, while their body structure gave them an advantage when it came to weight support. The long necks and sturdy limbs of sauropods, for example, allowed them to maintain adequate balance despite their massive size.
Between Earth and sea
Constraints also vary depending on the environment in which we live. Currently, the largest animal living on our planet is none other than the blue whale which, with its minimum 130 tonnes, easily beats the 5 tonnes of the African elephant, the largest land animal. Marine animals are, in fact, less subject to gravitygravity, which allows them to reach impressive sizes. In addition, water provides liftlift natural which facilitates the support of body weight, allowing marine animals to grow with less constraints.
Finally, last limit, and not the least: food requirements, which play a crucial role in the size of the animals. Herbivores require large areas of land to find enough food, which limits their potential size due to competition for food resources, the availability of which is limited. The fact remains that they are still much larger than carnivores. The reason: barbecue enthusiasts hunt their prey and need a lot of energy to catch their dinner.
However, the larger we are, the more energy we need, and the ratio energy spent hunting/energy obtained by eating is simply no longer balanced from a certain size. This is why the biggest carnivorouscarnivorous never known and marine dinosaur, the spinosaurus (spinosaurus), measured “only” about fifteen meters long, and half a dozen meters high.
We grant you, it’s already not bad, but almost touching next to Godzilla or King Kong.
