Your Legs are Poorly Designed

You’ve heard of exoskeletons (‘bones outside’) and you’ve heard of endoskeletons (the opposite). The obvious question to ask is “which is better,” and while it’s probably impossible to give a definitive and overarching answer to such a question a newish paper can at least go some way to resolving the matter. By modelling bones as hollow cylinders with a radius and thickness the researchers were able to calculate optimal r/t ratios for resisting certain stresses. According to the abstract, locust tibias primarily deal with bending and is “optimized for this loading mode.” Crabs, meanwhile, endure both bending and compression and their ratio is thus an “ideal compromise to resist these two types of loading.” But because their leg bones are within the body, the tibias of vertebrates such as us have relatively smaller radii and greater wall thickness – according to this research, this situation is not optimal.

As is only to be expected, Brian Thomas runs with the fallacious “optimal insect = designed insect” argument in Optimized Engineering in Locust Legs, opening:

People instantly recognize intelligent engineering in a structure that has optimized size or shape. Optimum parameters don’t just happen. So when two mechanical engineers recently discovered optimum sizing in locust legs, to what did they attribute that high level of engineering?

Allow me to demonstrate an obvious problem with the idea that begins this article with an example: Continue reading