Along with cellulose which belongs to the domain of plants and provides the fibre so good for us and chitin, which is what insect exoskeletons and wings are made of – keratin. It has got to be one of the three natural super-substances without which life would be very difficult indeed. It is a structural protein that basically comes in two avatars: alpha keratin and beta keratin. The first is found in all vertebrates, the latter in reptiles and birds. Alpha keratin manifests itself in skin, hair, horns, hooves, claws and nails, while beta keratin is in beaks, feathers and talons of birds, the beautiful scales of snakes and in the shells of reptiles such as tortoises, turtles and terrapins. Keratin is what makes our skin waterproof and tough, and it is even present in the cell walls of our internal organs. In its hard, muscular avatar it arms buffaloes and rhinos with their horns, with which they can so easily disembowel a lion and a bear, with claws, that can rip your face right off with a single swipe. Keratin will absolutely not dissolve in water as well as organic solvents such as acetic acid and benzene; it really is one tough son of a gun. And it is something of a Jekyll and Hyde! It’s astonishing to think that this one substance can be present in soft silky human hair through which we so love running our fingers, in the fuzzy fur of a puppy, the warm cosiness of a Kashmir-wool pullover, as well as in the deadly horns of a buffalo or rhino, or the fearsomely hooked beak and grappling-iron talons of an eagle. The silk of insects and spiders is also made of keratin and a spider’s silken thread, maybe stronger than steel wire of the same diameter. I still remember how every so often we had to pull out hair from our Boxer’s bum, often in the middle of the road, after halting all traffic: the silly dog would investigate the wastepaper basket and snaffle up the hair my sisters removed from their hairbrushes and then panic and whirl like a dervish when it finally emerged from the other end! Cats, as we all know, regularly bring up hairballs. Even when buried, hair takes its own sweet time to decompose naturally – two to four years maybe, depending on temperature and humidity. If kept in cool, dark, places it can last for thousands of years as manifested by well-preserved, excavated mummies. But, unlike plastic, it ultimately does decompose naturally, being broken down by enzymes and bacteria into its various components including nitrogen, carbon and sulphur. In nature, nothing is really ever wasted and everything is recycled. That’s something we really need to take heed of and prioritise these days. Because of its ‘recalcitrant’ nature, hair and fur can be hard to dispose of. This can be advantageous when seeking the DNA of long-dead and buried people to establish genetic links with the living. But when dumped in large tangled clumps it clogs up drains and water-ways – and even your shower outlet. We can and do, of course, recycle hair: directly in the form of wigs, and use the fur of some unfortunate animals like foxes and seals for coats and hats. Recently, I read that Indian students somewhere have used human hair to reinforce concrete! In Australia, scientists are trying to use it in electronic devices. Really, it’s the natural way to go for this extraordinarily tough protein! Feathers, too, are made of keratin and look at how strong and versatile they are. From the hair-like filoplumes which some birds use as sensors and for flight orientation and balance, to the incredibly soft down feathers of ducklings and ducks, and the blizzard-proof impervious overcoats of King Penguins, to say nothing of the magnificent flight feathers of birds: all are keratin-reinforced. Feathers are light, strong, flexible, sometimes waterproof, each flight feather aerodynamically shaped to enable maximum lift and thrust and able to deal with the stresses of wind and storm. Many wild predators have recognised that horns and hooves are not the most appetising or nourishing parts of their meal and will either not eat them at all or let them pass through their gut and out again, unchanged. Also there is always the danger that horns and hooves may splinter and damage their mouths, stomachs and intestines if they are consumed. Tigers and other large carnivores regularly remove the fur of their kills before consuming them, shaking their heads in disgust as they spit out mouthfuls! Eagles, falcons and hawks pluck their victims, too, before consuming them. As for us? Men in southeast Asia pay astronomical amounts for small quantities of powdered rhino horn – again nothing but indigestible keratin – thinking it will make the ladies swoon into their arms. So much so that rhinos are now highly endangered all over the world and need to be deliberately dehorned so that they are not poached to extinction. Really, our stupidity seems to be as indestructible as keratin itself! Even now, hunters proudly display the heads (and horns) of their kills as trophies on their walls. For us, as an integral part of our skin keratin provides a waterproof armoured layer: Rub your fingertip consistently against a hard surface, or practice like a lunatic on an acoustic guitar with sharp steel strings and soon your sore fingertips will be protected from pain and damage by a tough callus, which you could say is keratin! This really is one super substance!
