Written and illustrated by Areeb Siddiqui- 06/08/2011
From the very first apes to climb down from the trees over 200,000 years ago to the modern people of today, it has been widely understood that the world can be a very dangerous place. This is why some hail Kevlar as one of the most influential discoveries of the century, having saved countless lives through its application to bullet- proof armour. It may come as a surprise then that the science behind this body armour is by no means new and was in fact mastered long before our species even existed.
Whilst a resident of the jungles of the late Cretaceous period didn’t have to deal with the threats of gun or knife crime, there was the issue of the razor sharp teeth and claws of their neighbours. Ankylosaurus was more than well suited for the dangers of the time. A 13,000 pound, 9 metre long fusion of vertebrae and bony plates, this creature was more of a walking fortress than a dinosaur. But what sets Ankylosaurus apart from the other dinosaurs of the time, or indeed some of the heavily armoured creatures of today?
Well the chain mail of this colossal herbivore was composed of hundreds and thousands of bony plates known as osteoderms which ranged in size from as small as a one piece coin to several dozen centimetres in diameter. However upon closer inspection, a startling revelation was made by Torsten Scheyer, a PhD student at Bonn University, Germany. Unlike a turtles’ shell where the plates are fused together, Ankylosaurus’ simply lay flat side by side. But so what? A large rigid structure such as a turtles’ shell or indeed a medieval knights armour may offer better protection to blunt trauma, however its brittle nature means that if enough force is applied it may shatter (as evidenced by the fragments of sea turtle shell found in the digestive tracts of some tiger sharks). The increased flexibility of Ankylosaurus’ armour meant it was able to deform slightly under pressure and then return to its original shape, making it effective to puncture wounds, or for the purposes of this article, a bullet.
However common sense (accompanied by the lack of rubber worn by military personnel) might tell you that it takes more than flexibility alone to stop a bullet, and to find out just what that is we need to take a closer look at the actual make-up of ankylosaurus’ osteoderms. Further study with a polarisation microscope revealed that the plates were far more complex than any of the osteoderms seen on the creatures of today (such as crocodiles and alligators). Scheyer discovered that a series of collagen fibres (a protein usually found in sinews, cartilage and connective tissues) were interwoven amongst the bone calcium of the plates, forming a regular pattern of layers which were interspersed in three dimensions. Within each layer the fibres were aligned parallel to one another and perpendicular to those in the layers above and below them. ‘The armour was thereby endowed with great strength in all directions’ Scheyer claims. The diagram below shows a cross section of the plates make up.
This internal structure is remarkably similar to the bullet proof vests of today, with glass or carbon fibres taking the place of the collagen. To give you an idea of how this works think of the netting used in football goals. When the ball hits the back of the goal, the reason it doesn’t rebound back onto the field is because the net is loose and brings the ball to a halt by dissipating its kinetic energy over a longer period of time (the energy a body has with virtue to its motion), this demonstrates the advantage of flexibility. Then if we look at the structure of the netting itself you’ll notice the stings have been woven into a square shaped pattern. As the ball hits the net its energy is transferred to all of the stings it makes contact with, each of these strings is connected to two more strings, which are in turn connected to two more and so on and so forth. So the energy which was contained by the football has been dissipated throughout the entire net meaning that the whole structure rather than just the impact area is working to bring that ball to a standstill.
So whilst this brief insight into bullet proof vests, dinosaurs and football goals hasn’t led to any significant breakthroughs in the field of body armour, one fact remains. An invention so coveted by scientists and soldiers alike is nothing but a sketchy interpretation of a design perfected by nature 65 million years ago, so the real question is, just how far behind are we? What else is there to be gleaned from the natural world around us? Perhaps we should look at our planet as more than just our home, but also the ultimate instruction manual.