“When you follow two separate chains of thought, Watson, you will find some point of intersection which should approximate the truth”, Sherlock Holmes in The Disappearance of Lady Francis Carfax by Arthur Conan Doyle
“To find gold, you must dig and search through tons of dirt.”
Let us begin by assuming that one must design a system to perform a complex function, for example a robot to be able to run in very rough terrain. Wheels are ideal for motion on smooth surfaces, but very poor candidates for a terrain full of large stones. There are animals capable of running very fast in rough terrain, so it is natural to turn attention to some of these animals.
Biomimesis is a scientific endeavor, because it strives to identify physical laws, but also an art close to sleuthing. The basic process is to identify the principal features, form, functions and processes of animals through study of the literature or through experimentation with animals, so as to achieve similar performance with man-made structures.
One must have a lot of patience in obtaining the necessary information and classifying it accordingly. It is the most laborious and frustrating part, and the least amenable to teaching. Fortunately, we can often rely on a wealth of data obtained by patient and thorough researchers in the animal and plant world.
Once the material is available, one must start by classifying and sorting the information and trying to extract patterns and obvious first conclusions. Hypotheses will spring from such information handling, so the next step is to test the hypotheses against existing data or by collecting new data from animals. For example, one realizes that all running animals (including humans) have long tendons in the legs, which act like springs. Why do all animals have spring-like tendons in the legs? To answer this question one must have the necessary understanding of muscle function, i.e. the literature survey must be on a deep and comprehensive level.
In the case of fast swimming fish one finds that:
- The dolphin, which is a mammal with bones;
- The shark that has no bones—it has cartilage; and
- The salmon and the tuna, regular bony fishes,
Swim in similar ways, through flexing of their body, despite their different origins. They flex their bodies, not only their tails, creating a traveling wave along their body.
For example, the dolphin has still legs that have atrophied and are useless (the “hands” are activating its pectoral fins): it could have been swimming through kicking, like terrestrial animals do. Likewise, there is a fish, called the trigger fish, that swims in the same way birds fly, by flapping its wings only—not its body. Yet, all large fast animals choose to swim underwater in the same way, which by the way requires an elaborate muscular structure and nervous system. This is called convergence, the process of developing the same function of operation despite original differences, and is an unmistakable sign of being close to the optimal solution.
