Horn (anatomy) facts for kids
Horns are part of the body of some animals. They grow on the animal's head. They are projections (things that stick out) made of hard skin. The horn has a lot of keratin in it, the same protein that is in human hair and nails.
Normally horned animals will have two horns, but the rhinoceros has just one horn in the middle of its head.
Animals often use their horns for fighting one another.
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:
- Giraffidae: Giraffes have one or more pairs of bony bumps on their heads, called ossicones. These are covered with furred skin.
- Cervidae: Most deer have antlers, 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, except for reindeer) and are shed and regrown each year.
- Rhinocerotidae: The "horns" of rhinoceroses are made of keratin, the same substance as fingernails, 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.
- Ceratopsidae: The "horns" of the Triceratops were extensions of its skull bones although debate exists over whether they had a keratin covering.
- Horned lizards (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 beetles) have horn-like structures on the head or thorax (or both). These are pointed outgrowths of the hard chitinous exoskeleton. Some (such as stag beetles) have greatly enlarged jaws, also made of chitin.
- Canidae: Golden jackals are known to occasionally develop a horny growth on the skull, which is associated with magical powers in south-eastern Asia.
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.
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 (horn fighting) for territory, dominance or mating 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 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 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 with true horns use them for cooling. The blood vessels in the bony core allow the horns to function as a radiator.
After the death of a horned animal, the keratin may be consumed by the larvae of the Horn Moth.
- Antlers, structures similar to horns
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Horn (anatomy) Facts for Kids. Kiddle Encyclopedia.