Horn (anatomy)

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A pair of horns on a male impala Male impala profile.jpg
A pair of horns on a male impala
Anatomy and physiology of an animal's horn Anatomy and physiology of animals A horn.jpg
Anatomy and physiology of an animal's horn

A horn is a permanent pointed projection on the head of various animals that consists of a covering of keratin and other proteins surrounding a core of live bone. Horns are distinct from antlers, which are not permanent. In mammals, true horns are found mainly among the ruminant artiodactyls,[ not verified in body ] in the families Antilocapridae (pronghorn) and Bovidae (cattle, goats, antelope etc.). Cattle horns arise from subcutaneous connective tissue (under the scalp) and later fuse to the underlying frontal bone. [1]

Contents

One pair of horns is usual; however, two or more pairs occur in a few wild species and in some domesticated breeds of sheep. Polycerate (multi-horned) sheep breeds include the Hebridean, Icelandic, Jacob, Manx Loaghtan, and the Navajo-Churro.

Horns usually have a curved or spiral 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). Partial or deformed horns in livestock are called scurs. Similar growths on other parts of the body are not usually called horns, but spurs, claws, or hooves, 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:

Many mammal species in various families have tusks, which often serve the same functions as horns, but are in fact oversized teeth. These include the Moschidae (Musk deer, which are ruminants), Suidae (Wild Boars), Proboscidea (Elephants), Monodontidae (Narwhals) and Odobenidae (Walruses). Polled 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 horns are the only examples of horns growing on people. [7]

Cases of people growing horns have been historically described, sometimes with mythical status. Researchers have not however discovered photographic evidence of the phenomenon. [8] There are human cadaveric specimens that show outgrowings, but these are instead classified as osteomas or other excrescences. [8]

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. [9]

Some people, notably The Enigma, have horn implants; that is, they have implanted silicone beneath the skin as a form of body modification. [10]

Animal uses of horns

Goat skull piece Goat skull (MAV FMVZ USP).jpg
Goat skull piece
African buffalo (both sexes have horns) Serengeti Bueffel2.jpg
African buffalo (both sexes have horns)

Animals have a variety of uses for horns and antlers, including defending themselves from predators and fighting members of their own species (horn fighting) for territory, dominance or mating priority. [11] [12] 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 savannahlike habitat are more likely to bear horns than small or camouflaged species. [13]

In addition, horns may be used to root in the soil or strip bark from trees. In animal courtship many use horns in displays. For example, the male blue wildebeest reams the bark and branches of trees to impress the female and lure her into his territory. Some animals such as goats with true horns use them for cooling with the blood vessels in the bony core allowing them to function as a radiator. [14]

After the death of a horned animal, the keratin may be consumed by the larvae of the horn moth.

Human uses of horns

Water buffalo horn used as a hammer with cleaver to cut fish in southeast China Water buffalo horn 01.JPG
Water buffalo horn used as a hammer with cleaver to cut fish in southeast China

Dehorning

In some instances, wildlife parks may decide to remove the horn of some animals (such as rhinos) as a preventive measure against poaching. Animal horns can be safely sawn off without hurting the animal (it is similar to clipping toe nails). [16] [17] [18] When the animal were to be poached, the animal is generally killed as it is shot first. Park rangers however may decide to tranquilize the animal instead to remove the horn.[ clarification needed ]

See also

Related Research Articles

<span class="mw-page-title-main">Ungulate</span> Group of animals that walk on the tips of their toes or hooves

Ungulates are members of the diverse clade Euungulata which primarily consists of large mammals with hooves. Once part of the clade "Ungulata" along with the clade Paenungulata, "Ungulata" has since been determined to be a polyphyletic and thereby invalid clade based on molecular data. As a result, true ungulates had since been reclassified to the newer clade Euungulata in 2001 within the clade Laurasiatheria while Paenungulata has been reclassified to a distant clade Afrotheria. Living ungulates are divided into two orders: Perissodactyla including equines, rhinoceroses, and tapirs; and Artiodactyla including cattle, antelope, pigs, giraffes, camels, sheep, deer, and hippopotamuses, among others. Cetaceans such as whales, dolphins, and porpoises are also classified as artiodactyls, although they do not have hooves. Most terrestrial ungulates use the hoofed tips of their toes to support their body weight while standing or moving. Two other orders of ungulates, Notoungulata and Litopterna, both native to South America, became extinct at the end of the Pleistocene, around 12,000 years ago.

<span class="mw-page-title-main">Artiodactyl</span> Order of mammals

Artiodactyls are mammals belonging to the order Artiodactyla. Typically, they are ungulates which bear weight equally on two of their five toes: the third and fourth, often in the form of a hoof. The other three toes are either present, absent, vestigial, or pointing posteriorly. By contrast, most perissodactyls bear weight on an odd number of the five toes. Another difference between the two is that many artiodactyls digest plant cellulose in one or more stomach chambers rather than in their intestine as perissodactyls do. The advent of molecular biology, along with new fossil discoveries, found that cetaceans fall within this taxonomic branch, being most closely related to hippopotamuses. Some modern taxonomists thus apply the name Cetartiodactyla to this group, while others opt to include cetaceans within the existing name of Artiodactyla. Some researchers use "even-toed ungulates" to exclude cetaceans and only include terrestrial artiodactyls, making the term paraphyletic in nature.

<span class="mw-page-title-main">Antelope</span> Term referring to an even-toed ruminant

The term antelope refers to numerous extant or recently extinct species of the ruminant artiodactyl family Bovidae that are indigenous to most of Africa, India, the Middle East, Central Asia, and a small area of Eastern Europe. Antelopes do not form a monophyletic group, as some antelopes are more closely related to other bovid groups, like bovines, goats, and sheep, than to other antelopes.

<i>Triceratops</i> Genus of ceratopsid dinosaur from the Late Cretaceous

Triceratops is a genus of chasmosaurine ceratopsian dinosaur that lived during the late Maastrichtian age of the Late Cretaceous period, about 68 to 66 million years ago in what is now western North America. It was one of the last-known non-avian dinosaurs and lived until the Cretaceous–Paleogene extinction event 66 million years ago. The name Triceratops, which means 'three-horned face', is derived from the Greek words trí- meaning 'three', kéras meaning 'horn', and ṓps meaning 'face'.

<span class="mw-page-title-main">Antler</span> Extensions of the skull found in animals of the family Cervidae (deer)

Antlers are extensions of an animal's skull found in members of the Cervidae (deer) family. Antlers are a single structure composed of bone, cartilage, fibrous tissue, skin, nerves, and blood vessels. They are generally found only on males, with the exception of reindeer/caribou. Antlers are shed and regrown each year and function primarily as objects of sexual attraction and as weapons.

<span class="mw-page-title-main">Shofar</span> Wind instrument made from an animal horn

A shofar is an ancient musical horn typically made of a ram's horn, used for Jewish religious purposes. Like the modern bugle, the shofar lacks pitch-altering devices, with all pitch control done by varying the player's embouchure. The shofar is blown in synagogue services on Rosh Hashanah and at the end of Yom Kippur; it is also blown every weekday morning in the month of Elul running up to Rosh Hashanah. Shofars come in a variety of sizes and shapes, depending on the choice of animal and level of finish.

<span class="mw-page-title-main">Bovidae</span> Family of mammals belonging to even-toed ungulates

The Bovidae comprise the biological family of cloven-hoofed, ruminant mammals that includes cattle, yaks, bison, buffalo, antelopes, sheep and goats. A member of this family is called a bovid. With 143 extant species and 300 known extinct species, the family Bovidae consists of 11 major subfamilies and thirteen major tribes. The family evolved 20 million years ago, in the early Miocene.

<span class="mw-page-title-main">Four-horned antelope</span> Small antelope from Asia (Tetracerus quadricornis)

The four-horned antelope, or chousingha, is a small antelope found in India and Nepal. Its four horns distinguish it from most other bovids, which have two horns. The sole member of the genus Tetracerus, the species was first described by French zoologist Henri Marie Ducrotay de Blainville in 1816. Three subspecies are recognised. The four-horned antelope stands nearly 55–64 centimetres (22–25 in) at the shoulder and weighs nearly 17–22 kilograms (37–49 lb). Slender with thin legs and a short tail, the four-horned antelope has a yellowish brown to reddish coat. One pair of horns is located between the ears, and the other on the forehead. The posterior horns are always longer than the anterior horns, which might be mere fur-covered studs. While the posterior horns measure 8–12 centimetres (3.1–4.7 in), the anterior ones are 2–5 centimetres (0.79–1.97 in) long.

<i>Einiosaurus</i> Ceratopsian dinosaur genus from Upper Cretaceous period

Einiosaurus is a genus of herbivorous centrosaurine ceratopsian dinosaur from the Upper Cretaceous of northwestern Montana. The name means 'bison lizard', in a combination of Blackfeet Indian eini and Latinized Ancient Greek sauros; the specific name (procurvicornis) means 'with a forward-curving horn' in Latin. Einiosaurus is medium-sized with an estimated body length at 4.5 metres (15 ft).

<i>Achelousaurus</i> Genus of ceratopsid dinosaur from North America

Achelousaurus is a genus of centrosaurine ceratopsid dinosaur that lived during the Late Cretaceous Period of what is now North America, about 74.2 million years ago. The first fossils of Achelousaurus were collected in Montana in 1987, by a team led by Jack Horner, with more finds made in 1989. In 1994, Achelousaurus horneri was described and named by Scott D. Sampson; the generic name means "Achelous lizard", in reference to the Greek deity Achelous, and the specific name refers to Horner. The genus is known from a few specimens consisting mainly of skull material from individuals, ranging from juveniles to adults.

<i>Zuul</i> Genus of armored ankylosaurine dinosaurs

Zuul is a genus of herbivorous ankylosaurine dinosaur from the Campanian Judith River Formation of Montana. The type species is Zuul crurivastator. It is known from a complete skull and tail, which represents the first ankylosaurin known from a complete skull and tail club, as well as the most complete ankylosaurid specimen thus far recovered from North America. The specimen also preserved in situ osteoderms, keratin, and skin remains.

<span class="mw-page-title-main">Pecora</span> Infraorder of mammals

Pecora is an infraorder of even-toed hoofed mammals with ruminant digestion. Most members of Pecora have cranial appendages projecting from their frontal bones; only two extant genera lack them, Hydropotes and Moschus. The name "Pecora" comes from the Latin word pecus, which means "cattle". Although most pecorans have cranial appendages, only some of these are properly called "horns", and many scientists agree that these appendages did not arise from a common ancestor, but instead evolved independently on at least two occasions. Likewise, while Pecora as a group is supported by both molecular and morphological studies, morphological support for interrelationships between pecoran families is disputed.

<i>Meiolania</i> Extinct genus of turtles

Meiolania is an extinct genus of meiolaniid stem-turtle native to Australasia throughout much of the Cenozoic. Meiolania was a large turtle, with the shell alone ranging from 0.7–2 m in length. Four species are currently recognized, although the validity of two of them is disputed. Meiolania was first described as a species of lizard related to Megalania by Richard Owen towards the end of the 19th century, before the continued discovery of additional fossils solidified its placement as a kind of turtle.

<i>Pelorovis</i> Extinct genus of cattle

Pelorovis is an extinct genus of African wild cattle which existed during the Pleistocene epoch. The best known species is Pelorovis oldowayensis from Olduvai Gorge in Tanzania, from the Early Pleistocene. The species "Pelorovis" antiquus from the Late Pleistocene-Holocene has since been moved into Syncerus, the same genus as living African buffalo.

<span class="mw-page-title-main">Armour (zoology)</span>

Armour or armor in animals is a rigid cuticle or exoskeleton that provides exterior protection against attack by predators, formed as part of the body usually through the thickening and hardening of superficial tissues, outgrowths or skin secretions. It is therefore mostly developed in prey species that are too slow or clumsy to outrun predators, or those that would stand their ground and fight, thus needing to shield vital organs against claw, talon or bite injuries.

<span class="mw-page-title-main">Ossicone</span> Horn-like structure of giraffes, okapi, and extinct relatives

Ossicones are columnar or conical skin-covered bone structures on the heads of giraffes, male okapi, and some of their extinct relatives. Ossicones are distinguished from the superficially similar structures of horns and antlers by their unique development and a permanent covering of skin and fur.

<i>Ninjemys</i> Extinct genus of turtle

Ninjemys oweni is an extinct large meiolaniid stem-turtle from Pleistocene Queensland and possibly New South Wales (Australia). It overall resembled its relative, Meiolania, save that the largest pair of horns on its head stuck out to the sides, rather than point backwards, the larger scales at the back of its skull and the tail club which is made up of only two tail rings rather than four. With a shell length of approximately 1 m it is a large turtle and among the largest meiolaniids. Ninjemys is primarily known from a well preserved skull and associated tail armor, which were initially thought to have belonged to the giant monitor lizard Megalania.

<span class="mw-page-title-main">Tragelaphini</span> Tribe of antelopes

The tribe Tragelaphini, or the spiral-horned antelopes, are bovines that are endemic to sub-Saharan Africa. These include the bushbucks, kudus, and the elands. The scientific name is in reference to the mythical creature the tragelaph, a Chimera with the body of a stag and the head of a goat. They are medium-to-large, tall, long-legged antelopes characterized by their iconic twisted horns and striking pelage coloration patterns.

<span class="mw-page-title-main">Brontotheriidae</span> Extinct family of odd-toed ungulates

Brontotheriidae is a family of extinct mammals belonging to the order Perissodactyla, the order that includes horses, rhinoceroses, and tapirs. Superficially, they looked rather like rhinos with some developing bony nose horns, and were some of the earliest mammals to have evolved large body sizes. They lived around 56–34 million years ago, until the very close of the Eocene.

<span class="mw-page-title-main">Conservation and restoration of bone, horn, and antler objects</span> Preservation of heritage collections

Conservation-restoration of bone, horn, and antler objects involves the processes by which the deterioration of objects either containing or made from bone, horn, and antler is contained and prevented. Their use has been documented throughout history in many societal groups as these materials are durable, plentiful, versatile, and naturally occurring/replenishing.

References

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  13. "Why Female Water Buffalo Have Horns but Impala Do Not?".
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  15. Chusid, Hearing Shofar: The Still Small Voice of the Ram's Horn, 2009, Chapter 3-6 - Ram's Horn of Passover <http://www.hearingshofar.com Archived 2010-03-28 at the Wayback Machine >. The book also posits that the ancient Hebrews and neighboring tribes used horns as weapons and as utensils.
  16. "How chopping off their horns helps save rhinos from poachers". The Guardian . 2018-05-31. Archived from the original on 2023-05-11.
  17. Cutting off horns to save rhinos from poachers
  18. Dehorning rhinos