A horn is a permanent tapered projection on the heads of various animals consisting of keratin cover and other proteins that surround the core of living bone. Horn is different from horn, which is not permanent. In mammals, the true horns are found mainly among the ruminants meaning, in families of Antilocapridae (pronghorn) and Bovidae (cattle, goats, antelopes etc.).
A pair of horns is common; however, two pairs or more occur in some wild species and breeds of pet sheep. Polikerates (many horned) sheep breeds include Hebridean, Icelandic, Jacob, Manx Loaghtan, and Navajo-Churro.
Horns usually have a curved or spiral shape, often with backs or embroidery. In many species only men have horns. Horns start growing soon after birth, and continue to grow throughout the life of the animals (except in pronghorns, which spill out the outer layer every year, but retain the bone core). Partial horns or defects in cattle are called scurs . Similar growths on other parts of the body are not usually called horns, but spurs, claws or nails depend on the part of the body in which they occur.
Video Horn (anatomy)
Growth of other horn
The term "horn" is also popularly applied to other hard and pointy features attached to animal heads in various other families:
- Giraffidae: Giraffes have one or more pairs of bony protrusions on their heads, called ossicones. It is covered with hairy skin.
- Cervidae: Most deer have horns, which are not true horns. When fully developed, the horn is a dead bone without a horn or a covering skin; they are covered solely by adults (usually men, except deer) and spilled and grow back every year.
- Rhinocerotidae: The rhinoceros "Horn" is made of keratin, the same substance as the fingernails, and grows continuously, but does not have a bone core.
- Chamaeleonidae: Many chameleons, especially the Jackson Chameleon, have horns on their skulls, and have a keratin cover.
- Ceratopsidae: The "horn" of Triceratops is the extension of the skull bone even though there is a debate about whether they have a keratin cover. Abelisauridae: abelisaurid theropods, such as Carnotaurus and Majungasaurus have frontal bone extensions that may be enclosed in some form of keratin integument.
- Horned lizards ( Phrynosoma ): These lizards have horns on their heads that have hard keratin covering the core of the bone, like a mammalian horn.
- Insects: Some insects (like rhinoceros beetles) have a horn-like structure on the head or thorax (or both). This shows the growth of hard chitinous exoskeleton. Some (like deer beetles) have enlarged jaws, also made of chitin.
- Canidae: The golden wolf is known to occasionally develop the growth of horns on the skull, which is associated with supernatural forces in Southeast Asia.
- Azendohsauridae: the skull of the triassic azendohsaurid archosauromorph Shringasaurus has two large forward-faced conical horns, possibly covered with a cornified sarong in life.
- Anhimidae: the horned screamer has a completely loose keratin spine connected to its skull.
Many species of mammals in different families have fangs, which often have the same function with horns, but in reality are teeth that are too big. These include Moschidae (deer deer, ruminants), Suidae (Wild Boars), Proboscidea (Elephant), Monodontidae (Narwhals) and Odobenidae (Walruses). Animals surveyed or pollards are usually horned (especially tamed) species whose horns have been removed, or that have not yet grown. In some cases, such animals have a small horn growth on the skin where their horns will be - this is known as scurs .
In humans
Cutanum horns are the only example of a horn that grows in humans. They are most often benign growth and can be removed by a razor.
Adult horn cases have been described historically, sometimes with mystical status. Researchers have not found any photographic evidence of the phenomenon. There are human cadaver specimens that show growth, but these are classified as osteomas or other excretives.
Human phenomena with horns have been observed in countries that lack advanced drugs. There are people who live, some in China, with skin horn cases, most common in the elderly.
Some people, especially The Enigma, have implant horns; that is to say, they have implanted silicon under the skin as a modified form of the body.
The erect penis is sometimes referred to in slang as "horn," but usually does not contain keratin. However, skin horns may grow on the penis, which may indicate cancer. Maps Horn (anatomy)
Use of an animal horn
Animals have various uses for horns and horns, including defending themselves from predators and members of their own battle species ( fighting horns ) for territory, domination or priority of mating. Horns usually only exist in males but in some species, females also have horns. It has been theorized by researchers that higher species that live in the open are more visible from further distances and are more likely to benefit from horns to defend themselves against predators. Female bovids that are not hidden from predators because of their large size or open savannahs such as habitats are more likely to have horns than small or disguised species.
In addition, the horn can be used to root in the ground or peel the bark from the tree. In dating animals use many horns on the screen. For example, the blue male reindeer stuffs tree bark and tree twigs to impress the females and lure them into its territory. Some animals with true horns use it for cooling. The blood vessels in the bone core allow the horn to function as a radiator.
Source of the article : Wikipedia
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