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Horn (anatomy)
Encyclopedia
Skin
-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...
on the head of various animals, consisting of a covering of horn (keratin
Keratin
Keratin refers to a family of fibrous structural proteins. Keratin is the key of structural material making up the outer layer of human skin. It is also the key structural component of hair and nails...
and other protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
s) surrounding a core of living bone
Bone
Bones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...
. True horns are found mainly among the ruminant
Ruminant
A ruminant is a mammal of the order Artiodactyla that digests plant-based food by initially softening it within the animal's first compartment of the stomach, principally through bacterial actions, then regurgitating the semi-digested mass, now known as cud, and chewing it again...
artiodactyls, in the families Antilocapridae (pronghorn
Pronghorn
The pronghorn is a species of artiodactyl mammal endemic to interior western and central North America. Though not an antelope, it is often known colloquially in North America as the prong buck, pronghorn antelope, or simply antelope, as it closely resembles the true antelopes of the Old World and...
) and Bovidae (cattle
Cattle
Cattle are the most common type of large domesticated ungulates. They are a prominent modern member of the subfamily Bovinae, are the most widespread species of the genus Bos, and are most commonly classified collectively as Bos primigenius...
, goat
Goat
The domestic goat is a subspecies of goat domesticated from the wild goat of southwest Asia and Eastern Europe. The goat is a member of the Bovidae family and is closely related to the sheep as both are in the goat-antelope subfamily Caprinae. There are over three hundred distinct breeds of...
s, antelope
Antelope
Antelope is a term referring to many even-toed ungulate species indigenous to various regions in Africa and Eurasia. Antelopes comprise a miscellaneous group within the family Bovidae, encompassing those old-world species that are neither cattle, sheep, buffalo, bison, nor goats...
etc.). One pair of horns is usual, but two pairs occur in a few wild species and in a few domesticated
Domestication
Domestication or taming is the process whereby a population of animals or plants, through a process of selection, becomes accustomed to human provision and control. In the Convention on Biological Diversity a domesticated species is defined as a 'species in which the evolutionary process has been...
breeds of sheep. Partial or deformed horns in livestock are called scurs.
Horns usually have a curved or spiral
Spiral
In mathematics, a spiral is a curve which emanates from a central point, getting progressively farther away as it revolves around the point.-Spiral or helix:...
shape, often with ridges or fluting. In many species only males have horns. Horns start to grow soon after birth, and continue to grow throughout the life of the animal (except in pronghorns, which shed the outer layer annually, but retain the bony core). Similar growths on other parts of the body are not usually called horns, but spur
Spur (biology)
A spur in botany is a spike, usually part of a flower.In certain plants, part of a sepal or petal develops into an elongated hollow spike extending behind the flower, containing nectar which is sucked by long-tongued animals . Plants with such structures include Delphinium, Aquilegia, Piperia, and...
s, claw
Claw
A claw is a curved, pointed appendage, found at the end of a toe or finger in most mammals, birds, and some reptiles. However, the word "claw" is also often used in reference to an invertebrate. Somewhat similar fine hooked structures are found in arthropods such as beetles and spiders, at the end...
s or hoof
Hoof
A hoof , plural hooves or hoofs , is the tip of a toe of an ungulate mammal, strengthened by a thick horny covering. The hoof consists of a hard or rubbery sole, and a hard wall formed by a thick nail rolled around the tip of the toe. The weight of the animal is normally borne by both the sole...
s, depending on the part of the body on which they occur.
Other hornlike growths
The term "horn" is also popularly applied to other hard and pointed features attached to the head of animals in various other families:- GiraffidaeGiraffidaeThe giraffids are ruminant artiodactyl mammals that share a common ancestor with deer and bovids. The biological family Giraffidae, once a diverse group spread throughout Eurasia and Africa, contains only two living members, the giraffe and the okapi. Both are confined to sub-saharan Africa: the...
: GiraffeGiraffeThe giraffe is an African even-toed ungulate mammal, the tallest of all extant land-living animal species, and the largest ruminant...
s have one or more pairs of bony bumps on their heads, called ossiconeOssiconeOssicones are horn-like protuberances on the heads of giraffes, male okapis, and their extinct relatives, such as Sivatherium, and the climacoceratids, such as Climacoceras. Only giraffids have true ossicones...
s. These are covered with furred skin. - Cervidae: Most deerDeerDeer are the ruminant mammals forming the family Cervidae. Species in the Cervidae family include white-tailed deer, elk, moose, red deer, reindeer, fallow deer, roe deer and chital. Male deer of all species and female reindeer grow and shed new antlers each year...
have antlerAntlerAntlers are the usually large, branching bony appendages on the heads of most deer species.-Etymology:Antler originally meant the lowest tine, the "brow tine"...
s, which are not true horns. When fully developed, antlers are dead bone without a horn or skin covering; they are borne only by adults (usually males) and are shed and regrown each year. - Rhinocerotidae: The "horns" of rhinocerosRhinocerosRhinoceros , also known as rhino, is a group of five extant species of odd-toed ungulates in the family Rhinocerotidae. Two of these species are native to Africa and three to southern Asia....
es are made of keratin and grow continuously, but do not have a bone core. - Chamaeleonidae: Many chameleons, most notably the Jackson's Chameleon, possess horns on their skulls, and have a keratin covering.
- CeratopsidaeCeratopsidaeCeratopsidae is a speciose group of marginocephalian dinosaurs including Triceratops and Styracosaurus...
: The "horns" of the TriceratopsTriceratopsTriceratops is a genus of herbivorous ceratopsid dinosaur which lived during the late Maastrichtian stage of the Late Cretaceous Period, around 68 to 65 million years ago in what is now North America. It was one of the last dinosaur genera to appear before the great Cretaceous–Paleogene...
were extensions of its skull bones although debate exists over whether they had a keratin covering. - Horned lizardHorned lizardHorned lizards are a genus of lizards which are the type genus of the family Phrynosomatidae. The horned lizard is popularly called a "horned toad", "horny toad", or "horned frog", but it is neither a toad nor a frog. The popular names come from the lizard's rounded body and blunt snout, which...
s (Phrynosoma): These lizards have horns on their heads which have a hard keratin covering over a bony core, like mammalian horns. - Insects: Some insects (such as rhinoceros beetleRhinoceros beetleThe Rhinoceros Beetles or Rhino Beetles are a subfamily of the scarab beetle family . Other common names – some for particular groups of rhino beetles – are for example Hercules beetles, unicorn beetles or horn beetles...
s) have horn-like structures on the head or thoraxThoraxThe thorax is a division of an animal's body that lies between the head and the abdomen.-In tetrapods:...
(or both). These are pointed outgrowths of the hard chitinChitinChitin n is a long-chain polymer of a N-acetylglucosamine, a derivative of glucose, and is found in many places throughout the natural world...
ous exoskeletonExoskeletonAn exoskeleton is the external skeleton that supports and protects an animal's body, in contrast to the internal skeleton of, for example, a human. In popular usage, some of the larger kinds of exoskeletons are known as "shells". Examples of exoskeleton animals include insects such as grasshoppers...
. Some (such as stag beetleStag beetleStag beetles are a group of about 1,200 species of beetle in the family Lucanidae, presently classified in four subfamilies Some species grow up to over 12 cm , but most are about 5 cm .-Overview:...
s) have greatly enlarged jaws, also made of chitin. - CanidaeCanidaeCanidae is the biological family of carnivorous and omnivorous mammals that includes wolves, foxes, jackals, coyotes, and domestic dogs. A member of this family is called a canid . The Canidae family is divided into two tribes: Canini and Vulpini...
: Golden jackalGolden JackalThe golden jackal , also known as the common jackal, Asiatic jackal, thos or gold-wolf is a Canid of the genus Canis indigenous to north and northeastern Africa, southeastern and central Europe , Asia Minor, the Middle East and southeast Asia...
s are known to occasionally develop a horny growthJackal's HornThe Jackal's Horn is a boney cone-shaped excrescence which can occasionally grow on the skulls of golden jackals. It is associated with magical powers in south-eastern Asia. This horn usually measures half an inch in length, and is concealed by fur...
on the skull, which is associated with magical powers in south-eastern Asia.
Many mammal species in various families have tusk
Tusk
Tusks are elongated, continuously growing front teeth, usually but not always in pairs, that protrude well beyond the mouth of certain mammal species. They are most commonly canines, as with warthogs, wild boar, and walruses, or, in the case of elephants and narwhals, elongated incisors...
s, which often serve the same functions as horns, but are in fact oversize teeth. These include the Moschidae (Musk deer, which are ruminants), Suidae
Suidae
Suidae is the biological family to which pigs belong. In addition to numerous fossil species, up to sixteen extant species are currently recognized, classified into between four and eight genera...
(Wild Boars), Proboscidea
Proboscidea
Proboscidea is a taxonomic order containing one living family, Elephantidae, and several extinct families. This order was first described by J. Illiger in 1881 and encompasses the trunked mammals...
(Elephant
Elephant
Elephants are large land mammals in two extant genera of the family Elephantidae: Elephas and Loxodonta, with the third genus Mammuthus extinct...
s), Monodontidae
Monodontidae
The cetacean family Monodontidae comprises two unusual whale species, the narwhal, in which the male has a long tusk, and the white beluga whale...
(Narwhal
Narwhal
The narwhal, Monodon monoceros, is a medium-sized toothed whale that lives year-round in the Arctic. One of two living species of whale in the Monodontidae family, along with the beluga whale, the narwhal males are distinguished by a characteristic long, straight, helical tusk extending from their...
s) and Odobenidae
Odobenidae
Odobenidae is a family of Pinnipeds. The only living species is walrus.In the past, however, the group was much more diverse, and includes more than ten fossil genera.- Taxonomy :All genera, except Odobenus, are extinct.*Prototaria...
(Walrus
Walrus
The walrus is a large flippered marine mammal with a discontinuous circumpolar distribution in the Arctic Ocean and sub-Arctic seas of the Northern Hemisphere. The walrus is the only living species in the Odobenidae family and Odobenus genus. It is subdivided into three subspecies: the Atlantic...
es).
Polled livestock
Polled livestock are livestock without horns, of species that normally have them. The term refers both to breeds or strains which are naturally polled through selective breeding and also to naturally horned animals which have been dehorned...
animals or pollards are those of normally-horned (mainly domesticated) species whose horns have been removed, or which have not grown. In some cases such animals have small horny growths in the skin where their horns would be – these are known as scurs.
On humans
Cutaneous hornCutaneous horn
Cutaneous horns, also known by the Latin name cornu cutaneum, are unusual keratinous skin tumors with the appearance of horns, or sometimes of wood or coral. Formally, this is a clinical diagnosis for a "conical projection above the surface of the skin." They are usually small and localized, but...
s are the only examples of horns growing on people. They are most often benign growths and can be removed by a razor.
Cases of people growing horns have been historically described, sometimes with mythical status. Researchers have not however discovered photographic evidence of the phenomenon. There are human cadaveric specimens that show outgrowings, but these are instead classified as osteoma
Osteoma
An osteoma is a new piece of bone usually growing on another piece of bone, typically the skull. It is a benign tumor.When the bone tumor grows on other bone it is known as "homoplastic osteoma"; when it grows on other tissue it is called "heteroplastic osteoma".Osteoma represents the most common...
s or other excrescence
Excrescence
Excrescence is something that is an outgrowth of something else. Depending on the subject matter, this may or may not be something abnormal and/or disfiguring.* Excrescence is the epenthesis of a consonant....
s. Theoretically, there may be children born with horns which are corrected with early surgical intervention. The phenomenon of humans with horns has been observed in countries lacking advanced medicine. There are living people, several in China, with cases of cutaneous horns, most common in the elderly.
Some people, notably The Enigma, have horn implants; that is, they have implanted silicone beneath the skin as a form of body modification
Body modification
Body modification is the deliberate altering of the human body for any non-medical reason, such as aesthetics, sexual enhancement, a rite of passage, religious reasons, to display group membership or affiliation, to create body art, shock value, or self expression...
.
Animal uses of horns
Animals have a variety of uses for horns and antlers, including defending themselves from predators and fighting members of their own species for territory, dominance or matingMating
In biology, mating is the pairing of opposite-sex or hermaphroditic organisms for copulation. In social animals, it also includes the raising of their offspring. Copulation is the union of the sex organs of two sexually reproducing animals for insemination and subsequent internal fertilization...
priority. Horns are usually present only in males but in some species, females too may possess horns. It has been theorized by researchers that taller species living in the open are more visible from longer distances and more likely to benefit from horns to defend themselves against predators. Female bovids that are not hidden from predators due to their large size or open Savannah
Savannah
Savannah or savanna is a type of grassland.It can also mean:-People:* Savannah King, a Canadian freestyle swimmer* Savannah Outen, a singer who gained popularity on You Tube...
like habitat are more likely to bear horns than small or camouflaged species.
In addition, horns may be used to root in the soil or strip bark from trees. In animal courtship
Courtship
Courtship is the period in a couple's relationship which precedes their engagement and marriage, or establishment of an agreed relationship of a more enduring kind. In courtship, a couple get to know each other and decide if there will be an engagement or other such agreement...
many use horns in displays. For example, the male blue wildebeest
Blue Wildebeest
The Blue Wildebeest , also called the Common Wildebeest, is a large antelope and one of two species of wildebeest. It grows to 115–145 cm shoulder height and attains a body mass of 168–274 kg. They range the open plains, bushveld and dry woodlands of Southern and East Africa, living for...
reams the bark and branches of trees to impress the female and lure her into his territory
Territory (animal)
In ethology the term territory refers to any sociographical area that an animal of a particular species consistently defends against conspecifics...
. Some animals with true horns use them for cooling. The blood vessels in the bony core allow the horns to function as a radiator
Radiator
Radiators are heat exchangers used to transfer thermal energy from one medium to another for the purpose of cooling and heating. The majority of radiators are constructed to function in automobiles, buildings, and electronics...
.
Human uses of horns
- Horned animals are sometimes hunted so their mounted head or horns can be displayed as a hunting trophyTrophy huntingTrophy hunting is the selective hunting of wild game animals. Although parts of the slain animal may be kept as a hunting trophy or memorial , the carcass itself is sometimes used as food....
or as decorative objects. This practice can be considered controversial, especially as some animals are threatened or endangered due to reduced populations partially from pressures of such hunting.
- Some cultures use bovid horns as musical instrumentMusical instrumentA musical instrument is a device created or adapted for the purpose of making musical sounds. In principle, any object that produces sound can serve as a musical instrument—it is through purpose that the object becomes a musical instrument. The history of musical instruments dates back to the...
s, for example the shofarShofarA shofar is a horn, traditionally that of a ram, used for Jewish religious purposes. Shofar-blowing is incorporated in synagogue services on Rosh Hashanah and Yom Kippur.Shofar come in a variety of sizes.- Bible and rabbinic literature :...
. These have evolved into brass instrumentBrass instrumentA brass instrument is a musical instrument whose sound is produced by sympathetic vibration of air in a tubular resonator in sympathy with the vibration of the player's lips...
s in which, unlike the trumpetTrumpetThe trumpet is the musical instrument with the highest register in the brass family. Trumpets are among the oldest musical instruments, dating back to at least 1500 BCE. They are played by blowing air through closed lips, producing a "buzzing" sound which starts a standing wave vibration in the air...
, the bore gradually increases in width through most of its length—that is to say, it is conicalCone (geometry)A cone is an n-dimensional geometric shape that tapers smoothly from a base to a point called the apex or vertex. Formally, it is the solid figure formed by the locus of all straight line segments that join the apex to the base...
rather than cylindricalCylinder (geometry)A cylinder is one of the most basic curvilinear geometric shapes, the surface formed by the points at a fixed distance from a given line segment, the axis of the cylinder. The solid enclosed by this surface and by two planes perpendicular to the axis is also called a cylinder...
. These are called hornHorn (instrument)The horn is a brass instrument consisting of about of tubing wrapped into a coil with a flared bell. A musician who plays the horn is called a horn player ....
s, though now made of metalMetalA metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...
.
- Drinking hornDrinking hornA drinking horn is the horn of a bovid used as a drinking vessel. Drinking horns are known from Classical Antiquity especially in Thrace and the Balkans, and remained in use for ceremonial purposes throughout the Middle Ages and the Early Modern period in some parts of Europe, notably in Germanic...
s are bovid horns removed from the bone core, cleaned and polished and used as drinking vessels. (See also the legend of the Horn of plenty, or CornucopiaCornucopiaThe cornucopia or horn of plenty is a symbol of abundance and nourishment, commonly a large horn-shaped container overflowing with produce, flowers, nuts, other edibles, or wealth in some form...
). It has been suggested that the shape of a natural horn was also the model for the rhytonRhytonA rhyton is a container from which fluids were intended to be drunk, or else poured in some ceremony such as libation. Rhytons were very common in ancient Persia, where they were called takuk...
, a horn-shaped drinking vessel.
- Powder hornPowder HornPowder Horn may mean:* Powder Horn , the device for carrying gunpowder*Powder Horn , the Venturing training program offered by the Boy Scouts of America...
s were originally bovid horns fitted with lids and carrying straps, used to carry gunpowderGunpowderGunpowder, also known since in the late 19th century as black powder, was the first chemical explosive and the only one known until the mid 1800s. It is a mixture of sulfur, charcoal, and potassium nitrate - with the sulfur and charcoal acting as fuels, while the saltpeter works as an oxidizer...
. Powder flasks of any material may be referred to as powder horns.
- Antelope horns are used in traditional Chinese medicine.
- Horns consist of keratinKeratinKeratin refers to a family of fibrous structural proteins. Keratin is the key of structural material making up the outer layer of human skin. It is also the key structural component of hair and nails...
, and the term "horn" is used to refer to this material, sometimes including similarly solid keratin from other parts of animals, such as hoofHoofA hoof , plural hooves or hoofs , is the tip of a toe of an ungulate mammal, strengthened by a thick horny covering. The hoof consists of a hard or rubbery sole, and a hard wall formed by a thick nail rolled around the tip of the toe. The weight of the animal is normally borne by both the sole...
s. Horn may be used as a material in tools, furnitureHorn furnitureHorn furniture is a name given to furniture are made from the horns and antlers of animals such as cattle , antelope, moose and elk.They were especally popular in the United Kingdom and The United States in the late 19th century....
and decoration, among other uses. In these applications, horn is valued for its hardness, and it has given rise to the expression hard as horn. Horn is somewhat thermoplasticThermoplasticThermoplastic, also known as a thermosoftening plastic, is a polymer that turns to a liquid when heated and freezes to a very glassy state when cooled sufficiently...
and (like tortoiseshellTortoiseshell materialTortoiseshell or tortoise shell is a material produced mainly from the shell of the hawksbill turtle, an endangered species. It was widely used in the 1960s and 1970s in the manufacture of items such as combs, sunglasses, guitar picks and knitting needles...
) was formerly used for many purposes where plasticPlasticA plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...
would now be used. Horn may be used to make glueGlueThis is a list of various types of glue. Historically, the term "glue" only referred to protein colloids prepared from animal flesh. The meaning has been extended to refer to any fluid adhesive....
.
- Horn bowsComposite bowA composite bow is a bow made from horn, wood, and sinew laminated together. The horn is on the belly, facing the archer, and sinew on the back of a wooden core. Sinew and horn will store more energy than wood for the same length of bow...
are bows made from a combination of horn, sinew and usually wood. These materials allow more energy to be stored in a short bow than wood alone.
- Horns and horn tips from various animals have been used for centuries in the manufacture of scales, grips, or handles for knives and other weapons, and beginning in the 19th century, for the handle scales of handgunHandgunA handgun is a firearm designed to be held and operated by one hand. This characteristic differentiates handguns as a general class of firearms from long guns such as rifles and shotguns ....
s.
- IvoryIvoryIvory is a term for dentine, which constitutes the bulk of the teeth and tusks of animals, when used as a material for art or manufacturing. Ivory has been important since ancient times for making a range of items, from ivory carvings to false teeth, fans, dominoes, joint tubes, piano keys and...
comes from the teeth of animals, not horns.
- "Horn" buttonButtonIn modern clothing and fashion design, a button is a small fastener, most commonly made of plastic, but also frequently of seashell, which secures two pieces of fabric together. In archaeology, a button can be a significant artifact. In the applied arts and in craft, a button can be an example of...
s are usually made from deer antlers, not true horn.
See also
- Horn (disambiguation)
- Horn (instrument)Horn (instrument)The horn is a brass instrument consisting of about of tubing wrapped into a coil with a flared bell. A musician who plays the horn is called a horn player ....
- Horned helmetHorned helmetEuropean Bronze Age and Iron Age helmets with horns are known from a few depictions, and even fewer actual finds. Such helmets mounted with animal horns or replicas of them were probably used for religious ceremonial or ritual purposes.-Prehistoric Europe:...
- Polled livestockPolled livestockPolled livestock are livestock without horns, of species that normally have them. The term refers both to breeds or strains which are naturally polled through selective breeding and also to naturally horned animals which have been dehorned...
- Tortoiseshell materialTortoiseshell materialTortoiseshell or tortoise shell is a material produced mainly from the shell of the hawksbill turtle, an endangered species. It was widely used in the 1960s and 1970s in the manufacture of items such as combs, sunglasses, guitar picks and knitting needles...
- ShofarShofarA shofar is a horn, traditionally that of a ram, used for Jewish religious purposes. Shofar-blowing is incorporated in synagogue services on Rosh Hashanah and Yom Kippur.Shofar come in a variety of sizes.- Bible and rabbinic literature :...