To answer this question, imagine a crocodile, a snake or a fish without scales. They would look odd. And even more, they would become so vulnerable. While looks are not so important, safety is. Considering the harsh conditions that animals live in, scales are like their armour that protect them. These animals are no less than knights with shining armour!
While all reptiles are definitely scaly, fishes and insects also have scales. The scales of reptiles develop from skin. They are made up of keratin, the same stuff that our fingernails are made of. Only that they are much thicker than our nails. As reptiles grow (and reptiles grow throughout their lives, though much slowly as they grow old) the scales also grow. They also shed scales to grow new ones. These big and thick scales come in very handy while warding off a predator. Fish scales on the other hand are very slimy. This sort of lubrication allows smooth movement of fishes in water. Plus, no free lunches for parasites! It’s not easy for them to make home on such slippery scales. Do you think fish shed their scales? The answer is No.
Scales are a life saver as they regulate temperature in animals. It is not a good thing if our body temperatures are not regulated (it happens with us when we get fever). Did scales first evolve for providing insulation or protection? Well it is a close call. Scales are usually found on cold-blooded animals – the ones whose body temperature change with that of the surroundings. Compared to fur, scales absorb or dissipate the heat more readily, as needed by these animals.
The scales also help the animals in camouflage. The tiny dark and light scales on butterfly wings are usually arranged in beautiful patterns to help them blend in the environment. Crocodiles and alligators have earthy colored scales to perfectly help them camouflage in muddy waters. A green tree python can hardly be spotted in the trees.
Many reptiles have vibrant colors and patterns produced by pigment cells in their skins. Remember dart frogs and some venomous snakes. This colorful display does exactly the opposite of camouflaging. It makes them stand out in the surroundings. Why? To announce loud and out that don’t dare eat me, I am poisonous!
Do you know what the shedding of scales by reptiles is called?
The process is called ecdysis, and is more commonly known as moulting or sloughing.