A Rhodesian Ridgeback (sex unknown) with "stud tail": the violet gland lost hair and appears as a dark dimple The violet gland or supracaudal gland is a

gland A gland is a Cell (biology), cell or an Organ (biology), organ in an animal's body that produces and secretes different substances that the organism needs, either into the bloodstream or into a body cavity or outer surface. A gland may also funct ...

located on the upper surface of the

tail The tail is the elongated section at the rear end of a bilaterian animal's body; in general, the term refers to a distinct, flexible appendage extending backwards from the midline of the torso. In vertebrate animals that evolution, evolved to los ...

of certain

mammal A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...

s, including

European badger The European badger (''Meles meles''), also known as the Eurasian badger, is a badger species in the family Mustelidae native to Europe and West Asia and parts of Central Asia. It is classified as least concern on the IUCN Red List, as it has a w ...

s and canids such as foxes, wolves, and the domestic dog, as well as the domestic cat. Like many other

ian

secretion Secretion is the movement of material from one point to another, such as a secreted chemical substance from a cell or gland. In contrast, excretion is the removal of certain substances or waste products from a cell or organism. The classical mec ...

glands, the violet gland consists of modified

sweat gland Sweat glands, also known as sudoriferous or sudoriparous glands, , are small tubular structures of the skin that produce sweat. Sweat glands are a type of exocrine gland, which are glands that produce and secrete substances onto an epithelial s ...

s and

sebaceous gland A sebaceous gland or oil gland is a microscopic exocrine gland in the skin that opens into a hair follicle to secrete an oily or waxy matter, called sebum, which lubricates the hair and skin of mammals. In humans, sebaceous glands occur in ...

s. It is used for intra-species signalling,

scent marking In ethology, territory is the sociographical area that an animal consistently defends against conspecific competition (or, occasionally, against animals of other species) using agonistic behaviors or (less commonly) real physical aggression. ...

, and contributes to the strong

odor An odor (American English) or odour ( Commonwealth English; see spelling differences) is a smell or a scent caused by one or more volatilized chemical compounds generally found in low concentrations that humans and many animals can perceive ...

of foxes in particular. Although it secretes a mixture of volatile

terpene Terpenes () are a class of natural products consisting of compounds with the formula (C5H8)n for n ≥ 2. Terpenes are major biosynthetic building blocks. Comprising more than 30,000 compounds, these unsaturated hydrocarbons are produced predomi ...

s similar to those produced by violets (hence the name), the

chemicals A chemical substance is a unique form of matter with constant chemical composition and characteristic properties. Chemical substances may take the form of a single element or chemical compounds. If two or more chemical substances can be combin ...

are produced in much greater quantity than in flowers, and the resulting strong smell can be quite unpleasant.

By species

In dogs, the violet or supracaudal gland is found approximately above the 9th caudal vertebra, but depending on breed it may be vestigial or entirely absent. The violet gland secretes protein and hydrophobic lipids, has wide excretory ducts, is connected with coarse hairs, devoid of cysts, and has no sexual dimorphism. In the dog and cat fancy it is often referred to as "

stud Stud may refer to: Animals * Stud (animal), an animal retained for breeding ** Stud farm, a property where livestock are bred Arts and entertainment * Stud (band), a British progressive rock group * The Stud (bar), a gay bar in San Francisco * ...

tail", despite the fact that it occurs in both sexes, not just breeding males. However, for reasons still unknown the hair at a dog's violet gland tends to fall out when

androgen An androgen (from Greek ''andr-'', the stem of the word meaning ) is any natural or synthetic steroid hormone that regulates the development and maintenance of male characteristics in vertebrates by binding to androgen receptors. This includes ...

levels are high over a prolonged time. In short-haired breeds the usually inconspicuous gland may thus appear as a noticeably sparsely haired patch, and it is this condition of the gland area that is most frequent in stud dogs. In foxes, the violet gland is found on the upper surface of the tail, at roughly one-third of the tail's length from the body, and measures about 25 by 7.5

millimeter 330px, Different lengths as in respect of the electromagnetic spectrum, measured by the metre and its derived scales. The microwave is between 1 metre to 1 millimetre. The millimetre (American and British English spelling differences#-re, -er, i ...

s in

red fox The red fox (''Vulpes vulpes'') is the largest of the true foxes and one of the most widely distributed members of the order Carnivora, being present across the entire Northern Hemisphere including most of North America, Europe and Asia, plus ...

es. Due to its role in

steroid A steroid is an organic compound with four fused compound, fused rings (designated A, B, C, and D) arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes t ...

hormone A hormone (from the Ancient Greek, Greek participle , "setting in motion") is a class of cell signaling, signaling molecules in multicellular organisms that are sent to distant organs or tissues by complex biological processes to regulate physio ...

metabolism Metabolism (, from ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the co ...

(and possibly production), foxes cannot be "de-scented" by removing this gland. For unknown reasons, the gland's secretions are

fluorescent Fluorescence is one of two kinds of photoluminescence, the emission of light by a substance that has absorbed light or other electromagnetic radiation. When exposed to ultraviolet radiation, many substances will glow (fluoresce) with color ...

ultraviolet Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of ...

light Light, visible light, or visible radiation is electromagnetic radiation that can be visual perception, perceived by the human eye. Visible light spans the visible spectrum and is usually defined as having wavelengths in the range of 400– ...

; this may result from the presence of

carotenoid Carotenoids () are yellow, orange, and red organic pigments that are produced by plants and algae, as well as several bacteria, archaea, and fungi. Carotenoids give the characteristic color to pumpkins, carrots, parsnips, corn, tomatoes, cana ...

References

External links

About FoxesNatural History of the European BadgerNatural History of the Red Fox
Badgers Foxes Glands Carnivora anatomy {{carnivora-stub