King Kong and Godzilla: Size does matter

Would the existence of King Kong be possible, a gorilla of such size climbing skyscrapers agily? It seems that science, a usual wet blanket for the movies, says no.

We are used to thinking proportionally: if a book costs five euros, two books cost ten euros; if going to this city by car takes three hours, going somewhere three times as far takes nine hours. We might think, therefore, that a gorilla twice as high as those which we are used to see would have head and feet twice as big …. But I’m afraid the scale thing isn’t that easy.

The body of a person or an animal could be considered as a frame similar to that of a building. The bones, those of the legs especially, play the role of supporting pillars. Since the material forming the frame is always the same (all humans and animals are made of flesh and bone … well, with the few exceptions of those including silicone and botox), the weight carried by the legs / pillars depends only on the volume, the bigger the size the bigger the weight.

Well, the pillar being able to support the weight or breaking under it depends on the weight it is able to carry by unity of surface. If the weight doubles, the legs’ width must double too. And there is the problem regarding the scale: if we take a normal gorilla and make its size ten times bigger to turn him into King Kong, his weight won’t grow at the same rate his surface does, but considerably faster.

That’s just a matter of maths: weight depends on volume. If we make body’s height, length and width ten times higher (in order to preserve the same proportions) weight gets 10 · 10 · 10 = 1000 times higher. Nevertheless, the legs bone's surface, which is bidimensional, only gets 10 · 10 = 100 times higher. A leg only 100 times bigger is supporting a body 1000 times bigger, so it turns 10 times weaker. The consequence is King Kong or Godzilla wouldn’t scare anyone, as they would crumble victims of several fractures the very same moment they would stand up.

This is even worse for insects and arachnids, the slim legs of which have to support exoskeletons (external backbones) too rigid and heavy for their size. That’s why invertebrate animals are quite limited in size: if they were bigger they would get their legs constantly fractured. Movies like Them! and others dealing with giant ants and bugs don’t happen to be very plausible.

The only viable solution for King Kong, Godzilla or The 50 ft women would be ruining their proportions and getting very much longer than tall. Their surface area would grow at the same rate as their weight this way, so that their feet would be able to support them. Of course they would be less photogenic, they would look more or less like this; the scope and the screens should be modified to watch them properly …. Size does matter!