What do a dinosaur and a bulletproof vest have in common? Here we explore the idea that our species may not be as advanced as we once thought
From our ancestors that journeyed out of Africa over 200,000 years ago to the garden variety of homo-sapiens found 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 past century, having saved countless lives through its application as bulletproof armour. It may come as a surprise then that the science behind this body armour is by no means new and was in fact developed millions of years 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 matter of the razor sharp teeth, claws and general unfriendly disposition of their neighbours. Ankylosaurus was more than well equipped for the dangers of its time. A six tonne, ten metre long fusion of vertebrae and scales that ended in a bony club at the tip of its tail, this creature was more of a walking fortress than a dinosaur. Some of you may recall that they even featured in last year’s Jurassic World taking on the flamboyantly named “Indominus Rex” before ultimately being overturned and devoured by the genetically engineered dinosaur (sloppy writing if you ask me).
So what set Ankylosaurus apart from other dinosaurs of the time, or indeed some of the more heavily armoured creatures of today? Well the chainmail of this colossal herbivore was composed of hundreds of thousands of bony plates known as ‘osteoderms’ that ranged in size from as small as a one pence coin to several dozen centimetres in diameter. However upon closer inspection, a startling revelation was made by Torsten Scheyer, a PhD palaeontology student at Bonn University, Germany. Unlike turtles’ shells where the plates are fused together, Ankylosaurus’ simply lay flat side by side. But so what?
A large rigid structure such as a turtle’s shell or a medieval knight’s 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 that came with Ankylosaurs’ un-fused armour meant it was able to deform slightly under pressure and then return to its original shape making it effective against tooth puncture wounds, blunt trauma from the tails of rivals or for the purposes of this article- a bullet.
However common sense (accompanied by the lack of rubber worn by military men and women) might tell you 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 Ankylosaurus’ osteoderms. Further study with a polarisation microscope revealed that the fossilised 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 woven amongst the bone calcium of the plates, forming a regular pattern of layers 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, not unlike the way synthetic polymer fibres are woven together in Kevlar vests. “The armour was thereby endowed with great strength in all directions” Scheyer stated. See the crudely constructed diagram below:
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 this works think f the netting used in football goals (soccer for those across the pond). When the ball hits the back of the net, the reason it doesn’t instantly rebound onto the field is because the net is loose and brings the ball to a halt by dissipating its kinetic energy (the energy a body has with virtue of its motion) over a longer period of time. This demonstrates the advantage of flexibility.
Then if we look at the structure of the net itself you’ll notice the strings have been woven into a a square shaped pattern. The instant the ball hits the net its energy is transferred to all of the strings it makes contact with. However 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 contained in the football has been dissipated throughout the entire net meaning that the whole structure rather than just the impact area is working to bring the ball to a standstill.
So whilst this brief insight into bullet proof vests, dinosaurs and football goals hasn’t led to any significant advancements in the field of materials science, one fact remains. An invention so coveted by scientists and military personnel alike, unintentionally replicates a design perfected by evolution 65 million years ago- so exactly how far behind are we? Scientists are beginning to look more and more to the natural world for solutions to a multitude of problems; from medicine, clean energy sources and even cyber-security. What if we could freeze our bodies for extended periods of time without damaging our cells irreparably like the Canadian wood-frog, or if our hearts could repair themselves when damaged like that of the zebra fish? The field of bio-mimicry is coming to the forefront as we start to view our world less as a wealth of resources to be exploited, but rather as the ultimate instruction manual.