Preorbital gland

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Preorbital gland
Rothirsch Spiesser Auge 2007-08-16 131.jpg
Subadult male red deer (Cervus elaphus). The preorbital gland is closed in this photograph.
Artery lacrimal artery
Nerve lacrimal nerve, Zygomatic nerve via Communicating branch, greater petrosal nerve
Latin glandula praeorbitalis
Anatomical terminology

The preorbital gland is a paired exocrine gland found in many species of hoofed animals, which is homologous to the lacrimal gland found in humans. These glands are trenchlike slits of dark blue to black, nearly bare skin extending from the medial canthus of each eye. They are lined by a combination of sebaceous and sudoriferous glands, and they produce secretions which contain pheromones and other semiochemical compounds. [1] Ungulates frequently deposit these secretions on twigs and grass as a means of communication with other animals. [2] [3]


The preorbital gland serves different roles in different species. Pheromone-containing secretions from the preorbital gland may serve to establish an animal's dominance (especially in preparation for breeding), [4] mark its territory, or simply to produce a pleasurable sensation to the animal. [5] Because of its critical role in scent marking, the preorbital gland is usually considered as a type of scent gland. A further function of these glands may be to produce antimicrobial compounds to fight against skin pathogens. Antimicrobial compounds found in these glands may be biosynthesized by the animal itself, or by microorganisms that live in these glands. [6]

In cervids

Photograph of a male red deer (Cervus elaphus), taken during the mating season. The prominent preorbital gland is enlarged and dilated. Red deer stag 2009 denmark.jpg
Photograph of a male red deer (Cervus elaphus), taken during the mating season. The prominent preorbital gland is enlarged and dilated.

Deer have seven types of external scent glands distributed across their bodies. These are the forehead glands (on the forehead), the preorbital glands (below the eyes), the nasal glands (inside the nostrils), the interdigital glands (between the toes), the preputial gland (inside the foreskin of the deer's penis), the metatarsal glands (outside of the hind legs), and the tarsal glands (located inside of the hind legs). [7] Although it is not their primary function, the salivary glands also function as scent glands. Deer rely heavily on the scent glands to communicate with other members of their species, and possibly even with members of other species. A deer may rub its preorbital gland (e.g., on a branch) purely for pleasure. [5]

North American deer

The two major species of deer found in North America are the white-tailed deer (Odocoileus virginianus) and the mule deer (Odocoileus hemionus). The most important sense in these animals is olfaction (the sense of smell)—so much so that they have an accessory olfaction system. The vomeronasal organ, located at the base of the nasal cavity, is the sensory organ for this system. Besides locating food and water, deer rely on their two separate olfactory systems to detect the presence of predators, as well as to supply them with information about the identity, sex, dominance status and reproductive status of other deer. [8]

The preorbital gland of O. virginianus is about 22 millimeters (0.87 in) in length, while that of O. hemionus is roughly 40 millimeters (1.6 in) in length. In black-tailed deer (O. h. columbianus), a subspecies of O. hemionus, the preorbital gland measures about 32 millimeters (1.3 in). [1] In all of these animals, the preorbital glands are surrounded by muscle which is under voluntary control, at least to some extent. [8]

It is not entirely clear whether the preorbital gland secretions of North American deer are significant for chemical communication. Most of the time the glands remain closed, but deer are capable of opening them to emit an odor in certain circumstances. For example, a rutting male may dilate its preorbital glands in order to signal aggression to another nearby male. Female deer often open their glands while caring for their young. [8]

Other deer

A male Pere David's deer (Elaphurus davidianus). Note the large preorbital gland extending from just below the orbit. Elaphurus davidianus at Sharkarosa Wildlife Ranch in Pilot Point, Texas.jpg
A male Père David's deer (Elaphurus davidianus). Note the large preorbital gland extending from just below the orbit.
A male sambar (Rusa unicolor) in Pench National Park, Madhya Pradesh, India. These animals are often referred to as "four-eyed deer", due to their large preorbital glands. Sambhar deer.jpg
A male sambar (Rusa unicolor) in Pench National Park, Madhya Pradesh, India. These animals are often referred to as "four-eyed deer", due to their large preorbital glands.

In juvenile red deer (Cervus elaphus), the preorbital gland appears to play a role in the response to stress. The preorbital gland is closed in a relaxed calf, whereas it is opened in a stressed calf. [10] One example of this is the signalling of hunger and satiety. Fawns open their preorbital glands as a signal that they are hungry, and close the gland after feeding, when they are no longer hungry. [11]

The adult Indian muntjac (Muntiacus muntjac) is a solitary animal, other than during the rut (mating season) and for the first six months after giving birth. Adult males in particular are widely separated. Marking grass and bushes with secretions from their preorbital glands appears to be involved in the acquisition and maintenance of territory. [12]

In bovids

Hirola (Beatragus hunteri) are often referred to as the "four-eyed antelope", due to their large preorbital glands Hirola2.jpg
Hirola (Beatragus hunteri) are often referred to as the "four-eyed antelope", due to their large preorbital glands

The bovids (family Bovidae) comprise some 140 species of ruminants in which at least the males bear unbranched, hollow horns covered in a permanent sheath of keratin. Most species of bovids have means of spacing themselves across their habitat; territorial behavior is the most consistent type of spacing behavior. [14]

Caprids (dwarf antelope, such as the sheep, goats, muskox, serows, gorals, and several similar species) use their preorbital glands to establish social rank. For example, when competition arises between two grazing sheep (Ovis aries), they have been observed to nuzzle each other's preorbital glands. By sending and receiving olfactory cues, this behavior appears to be a means of establishing dominance and of avoiding a fight, which would otherwise involve potentially injurious butting or clashing with the forehead. [15]

The antilopine bovids (dwarf antelope, such as the springbok, blackbuck, gazelles, dik-diks, oribi, and several similar species) have well-developed preorbital glands. [3]

Among the cephalophines, members of the Philantomba and Sylvicapra genera are all solitary animals which display territorial behavior and have well developed preorbital glands. Maxwell's duiker (Philantomba maxwellii) is a solitary animal which utilizes preorbital gland secretions to mark its territory. This behavior is observed most in adult males, less frequently in females, and less still in subadults of this species. [16] Secretions from the preorbital gland of the common duiker contain at least 33 different chemical compounds. Two thiazole compounds and an epoxy ketone are present in significantly higher concentrations in male than in female secretions, suggesting that they could serve as sex recognition cues. [17]

The alcephine bovids (wildebeests, hartebeests, hirola, bontebok, blesbok, and several similar species) have preorbital glands which secrete complex mixtures of chemical compounds. [3] The preorbital glands of the bontebok (Damaliscus pygargus pygarus) are larger in males than in females. Their secretions contain at least forty different chemical compounds, and are deposited on grass and twigs at the borders of their territory. They then appear to transfer the secretions from the grass to their horns and forehead by waving the head from side to side across the stalk bearing the secretion. Marking of plant stalks with preorbital gland secretions is seen in both sexes. [18] In contrast to the duikers and raphicerids, the klipspringer (Oreotragus oreotragus) is a semi-gregarious species, while the hirola (Beatragus hunteri) is fully gregarious. Nevertheless, these animals display territorial scent marking of grasses with secretions from their preorbital glands. [16] [19]

Differences in the social structure and marking behavior among different species may lead to a different size and position of the preorbital glands on the animal's face. For example, Günther's dik-dik (Madoqua guentheri) is a monogamous species of antelope that lives in a permanent territory, the boundaries of which the animals mark several times a day by actively pressing the preorbital glands to grasses and low-lying plants and applying the secretions. In this territorial animal, the preorbital glands remain of considerable size throughout the year. The glands are located in large preorbital pits in the lacrimal bone, and are surrounded by specialized facial muscles that compress them to express the secretions more effectively. In contrast, the saiga antelope (Saiga tatarica) is a polygamous and somewhat nomadic species which does not occupy any permanent territory at any time during the year. For most of the year the preorbital glands remain small, only growing to substantial size during the rut. At that time of year, secretions ooze more or less continuously from the glands. In this nonterritorial animal, the preorbital glands are not as well-developed, lack well-developed surrounding facial muscles, and are positioned in an inconspicuous and shallow depression of the lacrimal bone. [20]

Research directions

The recent identification of several antimicrobial compounds from the secretions of animal dermal scent glands may be the beginning of a promising new area of drug development. Assuming functional analogs of these lead compounds can be synthesized and found to be effective in vivo, the potential exists for producing new antimicrobial agents against pathogenic skin microorganisms. [6]

See also


  1. 1 2 Rue III, LL (2004). "External glands". The deer of North America. Guilford, Connecticut: Lyons Press. pp. 114–24. ISBN   1-59228-465-5.
  2. Albone, ES (1984). "Scent glands". Mammalian semiochemistry: the investigation of chemical signals between mammals. New York: John Wiley and Sons. pp. 74–134. ISBN   978-0471102533.
  3. 1 2 3 Burger, BV (2005). "Mammalian semiochemicals". In Schulz, S (ed.). The chemistry of pheromones and other semiochemicals II (PDF). Topics in current chemistry. Vol. 240. Berlin: Springer-Verlag. pp. 231–78. doi:10.1007/b98318. ISBN   3-540-21308-2. ISSN   0340-1022.
  4. Kile, TL; Marchinton, RL (1977). "White-tailed deer rubs and scrapes: spatial, temporal and physical characteristics and social role". The American Midland Naturalist. 97 (2): 257–66. doi:10.2307/2425092. JSTOR   2425092?.
  5. 1 2 "Understanding deer glands". Huntley, Illinois: Hunting Network, LLC. 2012. Retrieved 2012-05-21.
  6. 1 2 Wood, WF (2010). "Synthesis and antimicrobial activity of long-chain 3,4-epoxy-2-alkanones". Scientia Pharmaceutica. 78 (4): 745–51. doi:10.3797/scipharm.1009-02. PMC   3007617 . PMID   21179314.
  7. Nickens, TE (2009-11-05). "Understanding seven deer glands". Field & Stream Online. New York: Field & Stream. Retrieved 2012-05-27.
  8. 1 2 3 Miller, KV (1990). "Deer scent communication: what do we really know?" (PDF). Deer Hunters News. 10: 21–2. Archived from the original (PDF) on 2013-01-26.
  9. Leslie Jr., DM (2011). "Rusa unicolor (Artiodactyla: Cervidae)". Mammalian Species. 43 (1): 1–30. doi: 10.1644/871.1 .
  10. Bartosova-Vıchova, J; Bartos, L; Svecova, L (2007). "Technical note: Preorbital gland opening in red deer (Cervus elaphus) calves as an indicator of stress" (PDF). Journal of Animal Science. 85 (2): 494–6. doi:10.2527/jas.2006-446. PMID   17040951.[ permanent dead link ]
  11. Bartos, L; Vıchova, J; Lancingerova, J (2005). "Preorbital gland opening in red deer (Cervus elaphus) calves: Signal of hunger?" (PDF). Journal of Animal Science. 83 (1): 124–9. doi:10.2527/2005.831124x. PMID   15583051.[ permanent dead link ]
  12. Eisenberg, JF; McKay, GM (1974). "Comparison of ungulate adaptations in the new world and the old world tropical forests with special reference to Ceylon and the rainforests of Central America". In Geist, V; Walther, F (eds.). The behaviour of ungulates and its relation to management (PDF). Morges, Switzerland: International Union for Conservation of Nature and Natural Resources. pp. 584–602.
  13. Madar, A; Nadeau, M, eds. (2010). "Southern Kenya". Frommer's Kenya and Tanzania. Hoboken, New Jersey: Wiley Publishing, Inc. pp. 102–125. ISBN   978-0-470-28558-9.
  14. Bergerud, AT (1974). "Management of ungulate herds in relation to domestication". In Geist, V; Walther, F (eds.). The role of the environment in the aggregation, movement and disturbance behaviour of caribou (PDF). Morges, Switzerland: International Union for Conservation of Nature and Natural Resources. pp. 552–84.
  15. Baskin, LM (1974). "Management of ungulate herds in relation to domestication". In Geist, V; Walther, F (eds.). The behaviour of ungulates and its relation to management (PDF). Morges, Switzerland: International Union for Conservation of Nature and Natural Resources. pp. 530–41.
  16. 1 2 Bigalke, RC (1974). "Ungulate behaviour and management, with special reference to husbandry of wild ungulates on South African ranches". In Geist, V; Walther, F (eds.). The behaviour of ungulates and its relation to management (PDF). Morges, Switzerland: International Union for Conservation of Nature and Natural Resources. pp. 830–52.
  17. Burger, BV; Pretorius, PJ; Spies, HSC; Bigalke, RC; Grierson, GR (1990). "Mammalian pheromones VIII Chemical characterization of preorbital gland secretion of grey duiker, Sylvicapra grimmia (Artiodactyla: Bovidae)". Journal of Chemical Ecology. 16 (2): 397–416. doi:10.1007/BF01021773. ISSN   0098-0331. PMID   24263498. S2CID   42031611.
  18. Huffman, B (2004-03-22). "Damaliscus pygargus". Order Cetartiodactyla. Retrieved 2012-05-21.
  19. Huffman, B (2008-12-31). "Beatragus hunteri". Order Cetartiodactyla. Retrieved 2012-05-21.
  20. Frey, R; Hofmann, RR (1997). "Skull, proboscis musculature and preorbital gland in the saiga antelope and Guenther's dikdik (Mammalia, Artiodactyla, Bovidae)". Zoologischer Anzeiger. 235 (3–4): 183–99. Archived from the original on 2013-01-28.

Further reading

Related Research Articles

Antelope Term referring to an even-toed ruminant

The term antelope is used to refer to many species of even-toed ruminant that are indigenous to various regions in Africa and Eurasia.

Duiker Subfamily of antelopes

A duiker is a small to medium-sized brown antelope native to sub-Saharan Africa, found in heavily wooded areas. The 22 extant species, including three sometimes considered to be subspecies of the other species, form the subfamily Cephalophinae or the tribe Cephalophini.

Bovidae Family of mammals belonging to even-toed ungulates

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

Musk deer Genus of mammals

Musk deer can refer to any one, or all seven, of the species that make up Moschus, the only extant genus of the family Moschidae. Despite being commonly called deer, they are not true deer belonging to the family Cervidae, but rather their family is closely related to Bovidae, the group that contains antelopes, bovines, sheep, and goats. The musk deer family differs from cervids, or true deer, by lacking antlers and preorbital glands also, possessing only a single pair of teats, a gallbladder, a caudal gland, a pair of canine tusks and—of particular economic importance to humans—a musk gland.

Klipspringer Species of mammal

The klipspringer is a small antelope found in eastern and southern Africa. The sole member of its genus and subfamily/tribe, the klipspringer was first described by German zoologist Eberhard August Wilhelm von Zimmermann in 1783. The klipspringer is a small, sturdy antelope; it reaches 43–60 centimetres at the shoulder and weighs from 8 to 18 kilograms. The coat of the klipspringer, yellowish gray to reddish brown, acts as an efficient camouflage in its rocky habitat. Unlike most other antelopes, the klipspringer has a thick and coarse coat with hollow, brittle hairs. The horns, short and spiky, typically measure 7.5–9 cm.

Dik-dik Genus of antelopes found in eastern and southern Africa

A dik-dik is the name for any of four species of small antelope in the genus Madoqua that live in the bushlands of eastern and southern Africa.

Four-horned antelope 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.

Royal antelope Species of mammal

The royal antelope is a West African antelope, recognized as the world's smallest antelope. It was first described by Swedish zoologist Carl Linnaeus in 1758. It stands up to merely 25 centimetres (10 in) at the shoulder and weighs 2.5–3 kilograms (5.5–6.6 lb). A characteristic feature is the long and slender legs, with the hindlegs twice as long as the forelegs. Horns are possessed only by males; the short, smooth, spiky horns measure 2.5–3 centimetres (1.0–1.2 in) and bend backward. The soft coat is reddish to golden brown, in sharp contrast with the white ventral parts. In comparison to Bates's pygmy antelope, the royal antelope has a longer muzzle, broader lips, a smaller mouth and smaller cheek muscles.

Blue duiker Species of mammal

The blue duiker is a small antelope found in central, southern and eastern Africa. It is the smallest duiker. The species was first described by Swedish naturalist Carl Peter Thunberg in 1789. 12 subspecies are identified. The blue duiker reaches 32–41 centimetres (13–16 in) at the shoulder and weighs 3.5–9 kilograms (7.7–19.8 lb). Sexually dimorphic, the females are slightly larger than the males. The dark tail measures slightly above 10 centimetres (3.9 in). It has short, spiky horns, around 5 centimetres (2.0 in) long and hidden in hair tufts. The subspecies show a great degree of variation in their colouration. The blue duiker bears a significant resemblance to Maxwell's duiker.

Indian muntjac Barking deer (Muntiacus muntjak)

The Indian muntjac, also called the southern red muntjac and barking deer, is a deer species native to South and Southeast Asia. It is listed as Least Concern on the IUCN Red List.

Thomsons gazelle Species of gazelle

Thomson's gazelle is one of the best-known gazelles. It is named after explorer Joseph Thomson and is sometimes referred to as a "tommie". It is considered by some to be a subspecies of the red-fronted gazelle and was formerly considered a member of the genus Gazella within the subgenus Eudorcas, before Eudorcas was elevated to genus status. Thomson's gazelles can be found in numbers exceeding 200,000 in Africa and are recognized as the most common type of gazelle in East Africa. The Thomson's gazelle can reach speeds of 80–90 km/h (50–55 mph). It is the fourth-fastest land animal, after the cheetah, pronghorn, and springbok.

Scent gland Exocrine glands found in most mammals

Scent glands are exocrine glands found in most mammals. They produce semi-viscous secretions which contain pheromones and other semiochemical compounds. These odor-messengers indicate information such as status, territorial marking, mood, and sexual behaviour. The odor may be subliminal—not consciously detectable. Though it is not their primary function, the salivary glands may also function as scent glands in some animals.

Oribi Species of mammal

The oribi is a small antelope found in eastern, southern and western Africa. The sole member of its genus, it was described by the German zoologist Eberhard August Wilhelm von Zimmermann in 1783. Eight subspecies are identified. The oribi reaches nearly 50–67 centimetres (20–26 in) at the shoulder and weighs 12–22 kilograms (26–49 lb). It possesses a slightly raised back, and long neck and limbs. The glossy, yellowish to rufous brown coat contrasts with the white chin, throat, underparts and rump. Only males possess horns; the thin, straight horns, 8–18 centimetres (3.1–7.1 in) long, are smooth at the tips and ringed at the base.

Suni Species of antelope

The Suni is a small antelope. It occurs in dense underbrush from central Kenya to KwaZulu-Natal in South Africa.

Maxwells duiker Species of mammal

The Maxwell's duiker is a small antelope found in western Africa.

Red-flanked duiker Species of mammal

The red-flanked duiker is a species of small antelope found in western and central Africa in countries as far apart as Senegal and Sudan. Red-flanked duikers grow to almost 15 in (35 cm) in height and weigh up to 31 lb (14 kg). They have russet coats, with greyish-black legs and backs, and white underbellies. They feed on leaves, fallen fruits, seeds and flowers, and sometimes twigs and shoots. The adults are territorial, living in savannah and lightly wooded habitats, and the females usually produce a single offspring each year. They have lifespans of ten to fifteen years in captivity.

A cat pheromone is a chemical molecule, or compound, that is used by cats and other felids for communication. These pheromones are produced and detected specifically by the body systems of cats and evoke certain behavioural responses. The name of the pheromone that calms a cat is Apaisins.

Self-anointing in animals A behaviour whereby a non-human animal smears odoriferous substances over themselves

Self-anointing in animals, sometimes called anointing or anting, is a behaviour whereby a non-human animal smears odoriferous substances over themselves. These substances are often the secretions, parts, or entire bodies of other animals or plants. The animal may chew these substances and then spread the resulting saliva mixture over their body, or they may apply the source of the odour directly with an appendage, tool or by rubbing their body on the source.

Bovidae in Chinese mythology

Bovidae in Chinese mythology include various myths and legends about a group of biologically distinct animals which form important motifs within Chinese mythology. There are many myths about the animals modernly classified as Bovidae, referring to oxen, sheep, goats, and mythological types such as "unicorns". Chinese mythology refers to those myths found in the historical geographic area of China, a geographic area which has evolved or changed somewhat through history. Thus this includes myths in Chinese and other languages, as transmitted by Han Chinese as well as other ethnic groups. There are various motifs of animals of the Bovidae biological family in Chinese mythology. These have often served as allusions in poetry and other literature. Some species are also used in the traditional Chinese calendar and time-keeping system.

(<i>Z</i>)-6-Dodecen-4-olide Chemical compound

(Z)-6-Dodecen-4-olide is a volatile, unsaturated lipid and γ-lactone found in dairy products, and secreted as a pheromone by some even-toed ungulates. It has a creamy, cheesy, fatty flavour with slight floral undertones in small concentrations, but contributes towards the strong, musky smell of a few species of antelope and deer in higher concentrations.