| Scent gland | |
|---|---|
 | |
 The arrow is pointing to themetatarsal gland of aSika deer | |
| Details | |
| Identifiers | |
| Latin | glandula odorifera |
| MeSH | D012543 |
| Anatomical terminology | |
Scent gland areexocrine glands found in mostmammals. They produce semi-viscoussecretions which containpheromones and othersemiochemical compounds. These odor-messengers indicate information such as status,territorial marking, mood, andsexual behaviour. The odor may be subliminal—not consciously detectable.[1][2] Though it is not their primary function, thesalivary glands may also function as scent glands in some animals.
Theeven-toed ungulates (Artiodactyla) have many specialized skin glands, thesecretions of which are involved in semiochemical communication.[2] These glands include thesudoriferous glands (located on the forehead, between theantlers and eyes), thepreorbital glands (extending from the medialcanthus of each eye), thenasal glands (located inside the nostrils), the interdigital glands (located between the toes), thepreputial gland (located inside the foreskin of the penis), themetatarsal glands (located outside of the hind legs), the tarsal glands (locatedinside of the hind legs),[3] and the inguinal glands in the lower belly or groin area.[4]
Like many other species of Artiodactyla,deer have seven major external scent glands distributed throughout their bodies.[3] Deer rely heavily on these scent glands to communicate with other members of their species, and possibly even with members of other species. For example, malewhite-tailed deer (Odocoileus virginianus) are often seen working over ascrape. First, the animal scrapes at the dirt with itshooves, depositing the scent from his interdigital gland on the ground. After that, he may bite the tip off an overhanging branch, depositing secretions from his salivary glands onto the branch. He may then rub his face on the overhanging branch, depositing secretions from the sudoriferous and preorbital glands on it.[5]
The interdigital glands of male and female black-tailed deer contain three volatile ketones, 2-tridecanone, (E)-3-tridecen-2-one and (E)-4-tridecen-2-one. (E)-3-tridecen-2-one was shown to have antibiotic activity against some skin pathogens.[6][7] These compounds are absent from white-tailed deer interdigital glands, which contain a number of 2-methylcarboxylic acids.[8]
The tarsal gland appears to operate by a different mechanism than the other external scent glands. A behavior calledrub-urination is central to this mechanism. During rub-urination, the animal squats while urinating so that urine will run down the insides of its legs and onto its tarsal glands. The tarsal glands have a tuft of hair which is specially adapted to extract certain chemical compounds from theanimal's urine. For example, in theblack-tailed deer (Odocoileus hemionus columbianus), the major constituent of the tarsal gland secretion is alipid,(Z)-6-dodecen-4-olide. This compound does not originate in the tarsal gland itself, but rather it is extracted from the animal's urine by the tarsal hair tuft during the rub-urination process. In white-tailed deer, the presence and concentration of certain chemical compounds in the urine depend on the season, gender, reproductive status andsocial rank of the animals. This fact, along with the observation of rub-urination behavior in this animal (at least in the male) indicates that urine probably plays a role inolfactory communication in deer.[2]
Canids have several scent glands that are used inolfactory communication.[9] Thefossa has several scent glands. Likeherpestids it has aperianal skin gland inside ananal sac which surrounds the anus like a pocket. The pocket opens to the exterior with a horizontal slit below the tail. Other glands are located near the penis or vagina, with the penile glands emitting a strong odor. Like the herpestids, it has noprescrotal glands.[10]
Anal glands are found in allcarnivora includingwolves,[11]bears,[12]sea otters[13] andkinkajous.[14]
Scent glands.