Guard hair or overhair is the outer layer of hair of most mammals, which overlay the fur. Guard hairs are long and coarse and protect the rest of the pelage (fur) from abrasion and frequently from moisture. They are visible on the surface of the fur and usually lend a characteristic contour and colour pattern. Underneath the contour hair is the short, dense, fine down. There are three types of guard hair: awns, bristles, and spines. [1] [2] [3]
Guard hair (overhair) is the top or outer layer of the coat. Guard hairs are longer, generally coarser, and have nearly straight shafts that protrude through the layer of softer down hair. The distal end of the guard hair is the visible layer of most mammal coats. The guard hair is spread over most of the skin, constitutes the main mass of the fur, and gives the contour and color of the fur, from the combinations in different percentages of two pigments: brown and black eumelanin, and yellow and red pheomelanin. This layer has the most marked pigmentation and gloss, manifesting as coat markings that are adapted for camouflage or display. Guard hair repels water and blocks sunlight, protecting the undercoat and skin in wet or aquatic habitats, and from the sun's ultraviolet radiation. Guard hairs can also reduce the severity of cuts or scratches to the skin. Many mammals, such as the domestic dog and cat, have a pilomotor reflex that raises their guard hairs as part of a threat display when agitated. [1] [2] [3]
The three major types of guard hair recognized are awns, spines and bristles, although intermediates between these types are known. [1] [2] [3]
Awn hair is the most common type of guard hair, characterized by an expanded distal end, a thin base, and definitive growth. The shafts of the awn are thick and usually spindle-shaped (or blade- or shieldlike), thinning gradually at the tip. Spindle-shaped portion is hard and usually differently colored. Awns usually lie in one direction, giving the pelage a distinct contour. This type of hair is found in carnivorans. In equids, cattle, and on the face and legs of sheep, the covering bristles are shorter, stiffer, straighter, and inconspicuously spindled. [1] [2] [3]
Bristles are firm, generally long hairs in equids and bovids, some carnivorans, etc., that that grow continuously and form manes. The mane often varies by sex, serving to distinguish the sexes (sexual dimorphism). For example, male lions have a collar of long, hard outline hair that grows continuously and extends to the shoulders and forms a mane on the back of the neck. Bristles function as visual signals that augment facial expressions (e.g., lions) or body postures (e.g., horses). [1] [2] [3]
The guard hairs are sometimes modified to form defensive spines. Spines are the stiff, enlarged guard hairs that exhibit definitive growth and form the protective quills of echidnas, hedgehogs and especially porcupines. In porcupines, the cuticular scales are elongate and form barbs that make it difficult to remove imbedded spines. [1] [2] [3]
Hair is a protein filament that grows from follicles found in the dermis. Hair is one of the defining characteristics of mammals. The human body, apart from areas of glabrous skin, is covered in follicles which produce thick terminal and fine vellus hair. Most common interest in hair is focused on hair growth, hair types, and hair care, but hair is also an important biomaterial primarily composed of protein, notably alpha-keratin.
Porcupines are large rodents with coats of sharp spines, or quills, that protect them against predation. The term covers two families of animals: the Old World porcupines of family Hystricidae, and the New World porcupines of family Erethizontidae. Both families belong to the infraorder Hystricognathi within the profoundly diverse order Rodentia and display superficially similar coats of rigid or semi-rigid quills, which are modified hairs composed of keratin. Despite this, the two groups are distinct from one another and are not closely related to each other within the Hystricognathi. The largest species of porcupine is the third-largest living rodent in the world, after the capybara and beaver.
The New World porcupines, family Erethizontidae, are large arboreal rodents, distinguished by their spiny coverings from which they take their name. They inhabit forests and wooded regions across North America, and into northern South America. Although both the New World and Old World porcupine families belong to the Hystricognathi branch of the vast order Rodentia, they are quite different and are not closely related.
A bristle is a stiff hair or feather, either on an animal, such as a pig, a plant, or on a tool such as a brush or broom.
Urticating hairs or urticating bristles are one of the primary defense mechanisms used by numerous plants, almost all New World tarantulas, and various lepidopteran caterpillars. Urtica is Latin for "nettle", and bristles that urticate are characteristic of this type of plant, and many other plants in several families. This term also refers to certain types of barbed bristles that cover the dorsal and posterior surface of a tarantula's or caterpillar's abdomen. Many tarantula species eject bristles from their abdomens, directing them toward potential attackers. These bristles can embed themselves in the other animal's skin or eyes, causing physical irritation, usually to great discomfort. The term urticating hairs is a misnomer, as technically only mammals possess true hairs.
Awn hairs are the intermediate hairs in a mammal's coat. They are shorter than the guard hairs and longer than the down hairs. They help with insulation and protect the down hairs underneath. Most of the visible coat is made of this kind of hair.
The maned rat or (African) crested rat is a nocturnal, long-haired and bushy-tailed East African rodent that superficially resembles a porcupine. The world's only poisonous rodent, the maned rat borrows toxins from plants to fend off predators.
Coat is the nature and quality of a mammal's fur. In the animal fancy, coat is an attribute that reflects the quality of a specimen's breeding as well as the level of the animal's care, conditioning, and management. Coat is an integral aspect of the judging at competitions such as a conformation dog show, a cat show, a horse show, or a rabbit show.
A chaeta or cheta is a chitinous bristle or seta found in annelid worms,. Polychaete annelids, are named for their chaetae. In Polychaeta, chaetae are found as bundles on the parapodia, paired appendages on the side of the body. The chaetae are epidermal extracellular structures, and clearly visible in most polychaetes. They are probably the best studied structures in these animals. Segments bearing chaetae are called chaetigers.
In botany, an awn is either a hair- or bristle-like appendage on a larger structure, or in the case of the Asteraceae, a stiff needle-like element of the pappus.
The bristle-spined rat is an arboreal rodent from the Atlantic forest in eastern Brazil. Also known as the bristle-spined porcupine or thin-spined porcupine, it is the only member of the genus Chaetomys and the subfamily Chaetomyinae. It was officially described in 1818, but rarely sighted since, until December 1986, when two specimens - one a pregnant female - were found in the vicinity of Valencia in Bahia. Since then it has been recorded at several localities in eastern Brazil, from Sergipe to Espírito Santo, but it remains rare and threatened due to habitat loss, poaching and roadkills.
The brush-furred mice, genus Lophuromys are a group of rodents found in sub-Saharan Africa. They are members of the subfamily Deomyinae, a group only identifiable through molecular analysis. Lophuromys is also known as the brush-furred rats, harsh-furred rats or coarse-haired mice.
A shaving brush or shave brush is a small brush with a handle parallel to the bristles used to make lather from shaving soap or shaving cream and apply it to the face when shaving. Shave brushes are often decorative; antique handles are often made from materials such as ivory or even gold, though the bristle load may be composed of any number of natural or synthetic materials. The shave brush is used most often today by "wet shavers" in tandem with a single- or double-edged safety razor or a straight razor. However, this is not always the case, as shavers of all varieties may employ the tool.
Chestnut is a hair coat color of horses consisting of a reddish-to-brown coat with a mane and tail the same or lighter in color than the coat. Chestnut is characterized by the absolute absence of true black hairs. It is one of the most common horse coat colors, seen in almost every breed of horse.
Horse grooming is hygienic care given to a horse, or a process by which the horse's physical appearance is enhanced for horse shows or other types of competition.
In a zoological context, spines are hard, needle-like anatomical structures found in both vertebrate and invertebrate species. The spines of most spiny mammals are modified hairs, with a spongy center covered in a thick, hard layer of keratin and a sharp, sometimes barbed tip.
The long-tailed porcupine is a species of rodent in the family Hystricidae. It is monotypic within the genus Trichys, and is found in Brunei, Indonesia, and Malaysia.
Dog grooming refers to both the hygienic care and cleaning of a dog, as well as a process by which a dog's physical appearance is enhanced for showing or other types of competition. A dog groomer is a person who earns their living grooming dogs.
Fur is a thick growth of hair that covers the skin of mammals. It consists of a combination of oily guard hair on top and thick underfur beneath. The guard hair keeps moisture from reaching the skin; the underfur acts as an insulating blanket that keeps the animal warm.
A felted material is a hairy or filamentous (hairy-like) fibre that is densely packed or tangled, forming felt or felt-like structures.