Snakeskin may either refer to the skin of a live snake, the shed skin of a snake after

molting In biology, moulting (British English), or molting (American English), also known as sloughing, shedding, or in many invertebrates, ecdysis, is the manner in which an animal routinely casts off a part of its body (often, but not always, an outer ...

, or to a type of leather that is made from the hide of a dead snake. Snakeskin and scales can have varying patterns and color formations, providing protection via camouflage from predators. The colors and iridescence in these scales are largely determined by the types and amount of

chromatophores Chromatophores are cells that produce color, of which many types are Biological pigment, pigment-containing cells, or groups of cells, found in a wide range of animals including amphibians, fish, reptiles, crustaceans and cephalopods. Mammals and ...

located in the dermis of the snake skin. The snake's skin and scales are also an important feature to their locomotion, providing protection and minimizing friction when gliding over surfaces.

Skin of a living snake

In a living snake, its skin often deals with various forms of abrasion. To combat rough substrates, snakes have formed specialized and multilayered organizational

epidermal The epidermis is the outermost of the three layers that comprise the skin, the inner layers being the dermis and hypodermis. The epidermis layer provides a barrier to infection from environmental pathogens and regulates the amount of water relea ...

structures to provide a safe and efficient sliding locomotion when maneuvering over rough surfaces.

Display

Pattern formation

Snake Snakes are elongated, limbless, carnivorous reptiles of the suborder Serpentes . Like all other squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales. Many species of snakes have skulls with several more j ...

s can be ornately patterned. They can be striped, banded, solid, green, blue, yellow, red, black, orange, brown, spotted, or have a unique pattern all their own. These color schemes can serve many functions, including camouflage, heat absorption or reflection, or may play other, less understood roles. Melanin cells in the skin often overlap and form complex patterns and sheets that are highly recognizable. Sometimes the soft

integument In biology, an integument is the tissue surrounding an organism's body or an organ within, such as skin, a husk, shell, germ or rind. Etymology The term is derived from ''integumentum'', which is Latin for "a covering". In a transferred, or ...

of a snake is colored differently than their hard scales. This is often utilized as a method of predator determent.

Color and iridescence

Coloration of snakes is largely due to pigment cells and their distribution. Some scales have lightly colored centers, which arise from regions with a reduced cuticle. A thinner cuticle indicates that some sensory organ is present. Scales in general are numerous and coat the epidermis, and come in all shapes and colors. They are helpful in identification of snake species.

Chromatophores Chromatophores are cells that produce color, of which many types are Biological pigment, pigment-containing cells, or groups of cells, found in a wide range of animals including amphibians, fish, reptiles, crustaceans and cephalopods. Mammals and ...

in the dermis yield coloration when light shines through the corneal layer of the epidermis. There are many kinds of chromatophores. Melanophores yield brown pigmentation, and when paired with guanophores, yield grey. When paired with guanophores and lipophores, yellow results. When guanophores and allophores are added to melanophores, red pigment results.

Carotenoids Carotenoids (), also called tetraterpenoids, are yellow, orange, and red organic pigments that are produced by plants and algae, as well as several bacteria, and fungi. Carotenoids give the characteristic color to pumpkins, carrots, parsnips, co ...

also help produce orange and red colors. Dark snakes (dark brown or black in color) appear as such due to melanocytes that are active in the epidermis. When melanin is absent,

albino Albinism is the congenital absence of melanin in an animal or plant resulting in white hair, feathers, scales and skin and pink or blue eyes. Individuals with the condition are referred to as albino. Varied use and interpretation of the term ...

individuals result. Snakes do not possess blue or green pigments, instead these arise from guanophores, which are also called iridocytes. Iridocytes reside in the dermis, and are responsible for the iridescent appearance of many dark-colored snakes. Males and females may show varied coloration, as might hatchlings and adults of the same species.

Structures and function

Snakeskin, or

, is more than just patterns and scales. Scales and patterning are features of snakeskin, and they are derived from a soft and complex integument. These scale patterns are unique to species, and the scales themselves help in locomoting by providing a friction buffer between the snake and the ground

Organization

Reptiles, including snakes, possess extensive

keratinization Keratin () is one of a family of structural fibrous proteins also known as ''scleroproteins''. Alpha-keratin (α-keratin) is a type of keratin found in vertebrates. It is the key structural material making up scales, hair, nails, feathers, h ...

of the epidermis in the form of epidermal scales. A snake's epidermis is composed of four layers. The outer layer of a snake's skin is shed periodically, and is therefore a temporary layer, and is highly keratinized. Beneath the outer layer is the corneal layer ( stratum corneum), which is thickened and flexible. Under the corneal layer is intermediary zone (

stratum granulosum The stratum granulosum (or granular layer) is a thin layer of cells in the epidermis lying above the stratum spinosum and below the stratum corneum ( stratum lucidum on the soles and palms).James, William; Berger, Timothy; Elston, Dirk (2005) '' ...

) and the basal layer (

stratum basale The ''stratum basale'' (basal layer, sometimes referred to as ''stratum germinativum'') is the deepest layer of the five layers of the epidermis, the external covering of skin in mammals. The ''stratum basale'' is a single layer of columnar or ...

), respectively. The dermis of a snake resides beneath the epidermis. The dermis of snakes is generally fibrous in nature, and not very prominent. The dermis houses pigment cells, nerves, and collagen fibers. Nerve fibers extend into the snake epidermis and anchor near scales, generally at the rostral, or head, end of the snake. Specifically, nerves anchor to sensory spines and pits, which are touch and thermal detection organs, respectively. The

hypodermis The subcutaneous tissue (), also called the hypodermis, hypoderm (), subcutis, superficial fascia, is the lowermost layer of the integumentary system in vertebrates. The types of cells found in the layer are fibroblasts, adipose cells, and macro ...

is below the dermis, this layer mainly stores fat.

Friction reduction and protection

The skin of a snake is a physically protective layer. It helps prevent injury, prevents drying out, and helps snakes to minimize friction. Snakeskin is composed of a soft, flexible inner layer (alpha-layer), as well as a hard, inflexible outer surface (beta-layer). Due to lack of limbs, snake bodies are in contact with a surface at all times, causing a large amount of friction. As a result, they have to both minimize friction in order to move forward, and generate their own friction in order to create enough propulsion to move. Scale and skin orientation helps to accomplish this, as it has been demonstrated that nanostructures on their scales may play a role in this process. Specifically, the inner alpha-layer contains alpha-keratins which serve as cytoskeletal proteins for a mechanical form of resistance against traction. Additionally to reduce friction, some snakes polish their scales. They secrete an oily substance from their nasal passage, and then rub the secretion all over the scales. This is done at varying intervals depending on the species of snake, sometimes frequently, other times only after shedding or molting. It is thought that scale polishing is used as a method of waterproofing, and it may also play a role in chemical messaging or friction reduction. Lastly, scales and snake skin provide protection in the form of keratin. It has been found, that beta-keratins aid in formation of scales, as the keratin proteins produce a pre-corneous layer of densely packed epidermal scales creating a thick

corneous Corneous is a biological and medical term meaning horny, in other words made out of a substance similar to that of horns and hooves in some mammals. The word is generally used to describe natural or pathological anatomical structures made out ...

protective layer.

Permeability

Skin permeability may change seasonally in snakes to help with the problem of drying out. It is known that desert snakes have generally impermeable skins, and that aquatic snakes have a more permeable skin that can sometimes trap water to prevent drying out. Some snakes may change their environment throughout the year, and may subsequently change their skin's permeability as a result. For instance, aquatic snakes may latch on to more water if they are in an environment that is drying out by attracting a layer of water under their scales.

Glands

Not many glands are present in snake skin. Most snake glands are holocrine glands, meaning that the gland's cells are secreted along with the substance the gland makes. These holocrine glands in snakes do not have their own blood supply, and thus lie closely with vascularized connective tissue. Snakes also possess glands that aid in attracting mates, and some marine snake species possess a

salt gland The salt gland is an organ for excreting excess salts. It is found in the cartilaginous fishes subclass elasmobranchii (sharks, rays, and skates), seabirds, and some reptiles. Salt glands can be found in the rectum of sharks. Birds and reptiles ...

that helps remove excess salt that they have consumed. Most glands in reptiles are poorly understood due to their scarcity.

Movement and flexibility

The skin that lies beneath snake's scales is also responsible for snakes' flexibility. The regions between snake scales is made of soft integument called an alpha-layer, which is composed of alpha-keratin that allows for flexibility and movement.Snake mobility is dependent on the skin's contact to a friction surface, the tribological behavior of the snake skin allows for quick and precise changes in direction. For smooth gliding to occur, snakeskin is composed of sharp spines and interlocking logitudinal ridges. The snakeskin also contains highly organized 'micro-hairs' along the

ventral Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

(underneath) surface, oriented in a caudal (towards the back) direction. With both of these features, the snake is able to efficiently slide forward on surfaces of low friction, and create high friction when needing to retreat backwardly.

Phylogeny

Snakes belong to a group of reptiles called the

Lepidosauria The Lepidosauria (, from Greek meaning ''scaled lizards'') is a subclass or superorder of reptiles, containing the orders Squamata and Rhynchocephalia. Squamata includes snakes, lizards, and amphisbaenians. Squamata contains over 9,000 species ...

, which are reptiles with overlapping scales. They further are grouped down into the

Squamata Squamata (, Latin ''squamatus'', 'scaly, having scales') is the largest order of reptiles, comprising lizards, snakes, and amphisbaenians (worm lizards), which are collectively known as squamates or scaled reptiles. With over 10,900 species ...

, which includes all snakes and lizards, and all but two species of Lepidosauria that belong to the Rynchocephalia (the

tuatara Tuatara (''Sphenodon punctatus'') are reptiles endemic to New Zealand. Despite their close resemblance to lizards, they are part of a distinct lineage, the order Rhynchocephalia. The name ''tuatara'' is derived from the Māori language and m ...

). The species belonging to both of these subgroups likewise share similar skin features with snakes, with unique adaptations and features, respectively.

Shed skin

The molting of the skin occurs regularly in snakes.

Molting In biology, moulting (British English), or molting (American English), also known as sloughing, shedding, or in many invertebrates, ecdysis, is the manner in which an animal routinely casts off a part of its body (often, but not always, an outer ...

is common, and results in the entire outer layer of epidermis being lost. In the case of snakes, it is called ''shedding'' or '' ecdysis.'' Snakes will rub against rough surfaces to shed their skin. A shed skin is much longer than the snake that shed it, as the skin covers the top and bottom of each scale. If the skin is shed intact, each scale is unwrapped on the top and bottom side of the scale which almost doubles the length of the shed skin. While a snake is in the process of shedding the skin over its eye, the eye may become milky. This impairs the vision of the snake and may result in aggressive behavior.

Leather

Snakeskin is used to make clothing such as vests, belts, boots or shoes or fashion accessories such as

handbag A handbag, commonly known as a purse or pocketbook in North American English, is a handled medium-to-large bag used to carry personal items. Purse, handbag or pouch The term "purse" originally referred to a small bag for holding coins. In man ...

s and

wallet A wallet is a flat case or pouch often used to carry small personal items such as paper currency, credit cards; identification documents such as driver's license, identification card, club card; photographs, transit pass, business cards and ...

s, and is used to cover the sound board of some string musical instruments, such as the

banhu The ''banhu'' ( 板胡, pinyin: bǎnhú) is a Chinese traditional bowed string instrument in the huqin family of instruments. It is used primarily in northern China. ''Ban'' means a piece of wood and ''hu'' is short for ''huqin''. Like the mor ...

, sanxian or the

sanshin The is an Okinawan and Amami Islands musical instrument and precursor of the mainland Japanese (). Often likened to a banjo, it consists of a snakeskin-covered body, neck and three strings. Origins Its close resemblance in both appearance a ...

. Snake leather is regarded as an exotic product alongside alligator, crocodile, lizard,

ostrich Ostriches are large flightless birds of the genus ''Struthio'' in the order Struthioniformes, part of the infra-class Palaeognathae, a diverse group of flightless birds also known as ratites that includes the emus, rheas, and kiwis. There ...

, emu, camel, among others. With crocodile and lizard leathers, it belongs to the category of reptile leathers, with a scaly appearance. There is evidence that the harvest in at least some species of snakes killed for the leather industry is unsustainable and carried out in violation of national legislation in source countries. File:SnakeskinBoots1 gobeirne.jpg, Snakeskin boots in Arizona File:Cigarette Case MET DP291212.jpg,

Art Deco Art Deco, short for the French ''Arts Décoratifs'', and sometimes just called Deco, is a style of visual arts, architecture, and product design, that first appeared in France in the 1910s (just before World War I), and flourished in the Unite ...

snakeskin cigarette case, ca 1925 File:Shoes, pair woman's (AM 1996.55-1).jpg, Pair of woman's high heeled platform shoes, 1930s File:Texas straw hat with the ornament made of a rattlesnake's skin.jpg, A Texas straw hat with the ornament made of a rattlesnake's skin File:Vintage clutch (847652012).jpg, A vintage clutch with a fold-over closure, made of red snakeskin File:Sanxian.gif, Chinese

sanxian The (, literally "three strings") is a three-stringed traditional Chinese lute. It has a long fretless fingerboard, and the body is traditionally made from snake skin stretched over a rounded rectangular resonator. It is made in several siz ...

with snakeskin-covered sound board

Gallery

File:Python Skins Burma.jpg, Leather goods and skins of Burmese python (''

Python molurus bivittatus The Burmese python (''Python bivittatus'') is one of the List of largest snakes, largest species of snakes. It is native to a large area of Southeast Asia and is listed as Vulnerable species, Vulnerable on the IUCN Red List. Until 2009, it was co ...

'') and reticulated python ('' Python reticulatus reticulatus'') at a local shop at Mandalay, Burma File:Taxidermy of a snake skin.jpg, Snakeskin artifact File:Lamia by Herbert James Draper (1909).jpg, ''The

Lamia LaMia Corporation S.R.L., operating as LaMia (short for ''Línea Aérea Mérida Internacional de Aviación''), was a Bolivian charter airline headquartered in Santa Cruz de la Sierra, as an EcoJet subsidiary. It had its origins from the failed ...

'': In this 1909 painting by

Herbert James Draper Herbert James Draper ( (baptism record) – ) was an English Classicist painter whose career began in the Victorian era and extended through the first two decades of the 20th century. Life Born in London, the son of a fruit merchant named Joh ...

, Lamia has human legs and a snakeskin around her waist. There is also a small snake on her right forearm. File:Snakeskin.JPG, A shed snake skin in nature

References

{{Leather Leather Skin Snake anatomy Snake products