Snakes are covered with scales!
Snake scales are dry and not slimy. Unlike fish and amphibians, snakes do not cover their body with mucus. Snake scales are made of the keratin like our hair and fingernails.
A snake does not get more scales as it grows; the scales just get larger.
Snake scales are not separate pieces like fish scales. They are formed out of folds of a single layer of the outer skin. The folds are so ingenious that the scales overlap each other! The skin between scales is soft and stretchy so the body can expand to eat large prey
The scales on a snake are of different sizes and shapes: A special transparent scale covers the eye (it's called the brille or spectacle!). Smaller scales at the mouth and body sides allow more expansion. Larger scales on the belly and head protect the snake. Belly scales are often oblong shaped to help the snake grip the surface.
Scales are transparent: All colours except blue and green are formed on the inner layer of the skin and not the scale itself. Blue is created by crystalline substances in the scale surface which diffracts light. Green is created by combining blue with yellow on the inner layer. These crystals also cause beautiful iridescence, especially in snakes with smooth scales.
Unlike chameleons and some lizards, snakes don't change colours quickly. Some, however, can lighten or darken slowly, in about an hour. They may be lighter in the day and darker at night for camouflage, or darker in cooler seasons to better absorb light. Some have different coloured or marked individuals, even in the same locality. Others have babies and juveniles of a radically different colour than adults; the Emerald Tree Boa (Corallus canina) juvenile is bright brick red and turns leaf green as an adult. The purpose is not known.
Each snake species has a unique scale pattern: Experts can often tell the species of a snake just by looking at an intact shed skin of a snake (slough). A healthy snake sheds its skin in one piece. The shed skin looks like a discarded nylon stocking and retains all the scale details.
What are the uses of scales?
Scales help in snakes move and to grip prey: Belly scales are broad, to grip the surface. Seasnakes have tiny granular scales for a sand-papery skin that grip slippery fish. Burrowing snakes have small smooth scales for quick tunnelling. Desert snakes have rough scales for gripping loose sand.
Scales protects from wear and tear: Snakes' eyes are covered by transparent spectacle scales. They have no movable eyelids, unlike lizards. The desert dwelling Horned Viper (left) has horny scales its eyes to protect it from the sun--serpent shades! Some burrowing snakes have large tough scales on their noses to protect the head as they dig.
Scales also protect snakes from predators: The scales form designs which camouflage the snake or to scare off predators. Can you find the TWO Gaboon Vipers in the photo on the right?! The Rattlesnake has dried scales at the end of its tail to make its typical warning noise. Some snakes have rough (keeled) scales which they rub together to make warning noises.
Why does a snake moult its skin? Snakes moult because the old skin gets worn out and not because the skin gets tight (after all, a snake's skin can stretch enormously to accommodate the prey that is swallowed!). Moulting also gets rid of parasites like mites and ticks. In fact even humans shed old skin, we just don't do it in one piece like snakes!
Before a moult, the bottom layer of the old skin liquidates and separates from the new skin forming below. This makes the old skin appear dull and causes the eye scales to cloud. As the snake's vision is affected and it generally feels uncomfortable, it will hide in a safe place and stop eating. When moulting, snakes get grumpy and can be unusually aggressive.
To get out of the old skin, a snake breaks the old skin around its lips by rubbing against a rough surface. It then crawls out of the old skin turning it inside out like a long sock, usually moving over a rough surface which catches on the old skin. Marine snakes that float on the ocean all their lives get the old skin off by coiling their bodies into complex knots. So the old skin is often found all knotted up!
Unlike lizards, snakes shed in one piece and don't eat their shed. It can take several hours to complete a moult. Sometimes a moult doesn't progress properly and small patches of the old skin stay stuck on the snake. If these eventually come loose there is no problem. But if they don't, infection may set in leaving permanent disfiguring scars.
How often do snakes moult? Young snakes moult more frequently than old snakes. An injured snake may moult sooner and more frequently to renew damaged skin. Moults can be as frequent as once every 20 days, and as rare as once a year.
More about snakes
- What are snakes?
- Are snakes cold?
- Why are snakes long?
- What do snakes eat? Do they drink?
- How do snakes swallow?
- How do snakes hunt?
- Why and how do snakes kill?
Snake predators and how do snakes protect themselves?
Snake mating, eggs and babies
Where are snakes found?
Fascinating snake adaptations to various habitats
Snake bites and first aid
Snakes in danger: role and conservation and snakes in human culture
Snake records: biggest, smallest, deadliest and more
- More snakes
- More animals
- General snake links and references
Further informations in german can be found here!