The sense of smell is one of the earliest developed senses in existence, as well as one of the most important. Out of the subphylum Vertebrata, the class Mammalia have the greatest olfactory perception and the most specialized of noses. As well as in some other vertebrates, the sense of smell is distinct in mammals, but at the same time unlimited in its ability to tell the difference between smells.
The first people to notice the importance of scent glands in mammals were perfumers. These various glands produced the odours of musk, civet, castor, and ambergris. Musk is taken from the preputial glands of the musk deer, civet from the anal glands of the civet, castor from the castor gland of the beaver and ambergris from the intestines of the sperm whale (Macdonald and Brown 1985).
Although the olfactory lobes are not as large as in many lower vertebrates, as it has already been stated, in general, olfactory organs and structure are well developed in mammals. The level of development correlates with the animal’s habits. This means, animals that rely the most on olfaction in their behaviour have greater sense capabilities. Stemming from this idea, the uses of olfaction in mammals are many.
One of these uses, which includes many different behaviours, is social functioning. Odors can be used to convey messages within a population and these can be conditioned from experience (Jameson 1921). When encountering strangers of the same species, there are 3 basic patterns of olfactory investigation. These naso-anal, naso-genital, and naso-nasal contact points are where investigation most often occur (Macdonald and Brown 1985). For example, when prairie dogs are fighting or irritated, their anal scent glans emit a strong musky odor which other prairie dogs can smell. Alternation of naso-anal smelling between male prairie dogs most often happens during disputes over territory (Cockrum 1962). Other gland regions can be investigated of course and this in seen in the red kangaroo. Males will lick or bite the patches of tubular glands on the chest or abdomen of other males. This happens when being threatened by another male (Dietland 1983).
A way for mammals to claim their territory without confrontation is by leaving scent marks. This behaviour is seen in nearly all male mammals in the form of urine, feces, by products from special gland regions left along the edges of the territory, or simply parts of the body that have been brushed up against trees or rocks for example (Doty 1976). ). While the leg lifting of the domestic dog is the most familiar example, the Brown Bear will combine two of these forms at the same time by urinating while scratching its back against a tree. An example of by products from glands is observed in two different species of mice who mouth or chew on tree branches and leave behind salvia from their mouths (Dietland 1983). Scent marks can be recognized by other...