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Abstract

Abstract-The scent-matching hypothesis postulates that scent marks provide an olfactory link between a resident owner and his territory, and that this enables intruding animals to recognize the chance of escalated conflicts. However, it is unclear if Eurasian beavers (Castor fiber) mark their own pelage with castoreum from their castor sacs (i.e., the same material used in territorial marking); and/or if beavers mark their pelage with anal gland secretion (AGS) from the anal glands to waterproof the pelage and to act as a "living-scent mark". Chemical analysis (gas chromatography and mass spectrometry) of hair samples from 22 live-trapped beavers revealed that castoreum compounds were not present in any samples, AGS compounds were found from 3 animals (13.6%) around the cloaca, and the compound squalene was found in all the samples. Beavers may release castoreum directly into the water when it meets an intruder. Thereby, the "scent mark" in the water can provide an olfactory link between a resident owner and his territory. Squalene, in contrast to AGS, may be essential for keeping beaver pelts water-repellant.

Mix it and fix it: functions of composite olfactory signals in ring-tailed lemurs

“…Recipient responses revealed that composite chemical signals probably function to increase the number of messages contained within a single scent mark. That recipient preference for the mixture strengthened after the secretions had decayed also supports the 'fixative' hypothesis [10,29,34,62], suggesting that, beyond contributing unique chemical information, lemur B secretions help preserve lemur A secretions. This latter interpretation is also supported by the pattern of recipient mixed countermarking to fresh and decayed signals.…”

“…By comparison, components of human speech, including pitch, amplitude and frequency, all convey different information and, thus, represent non-redundant elements of a vocal composite signal [25]. Based on descriptive studies, numerous taxa rely on composite chemosignals [26][27][28][29][30]; however, in only a handful of cases has the function of odorant mixtures been examined [10,31,32]. This under-representation may owe to the fact that, of the various types of composite signals, perhaps the most challenging to decipher are those involving olfactory elements.…”

“…According to the 'multiple-messages' hypothesis, if A and B secretions each encode unique information, mixing them may increase the information conveyed in a single scent mark [3,11,12], thereby increasing the interest of signal recipients. According to the 'fixative' hypothesis, adding viscous, long-lasting B secretions (S, in particular) to highly volatile A secretions may function to increase the longevity of A's information after deposition in the environment [10,29,34,60,62], thereby prolonging the signal's interest to recipients. Under this hypothesis, chemical elements would be non-redundant, but would not necessarily convey new information.…”

Behavioural Correlates of Lemur Scent-Marking in Wild Diademed Sifakas (Propithecus diadema) in the Maromizaha Forest (Madagascar)

“…Because scent-marking communicates the depositor’s identity/quality [ 28 , 29 ], the deployment of scent odours is always performed strategically [ 30 , 31 ]. Several species generate composite olfactory signals/cues by combining scent odours from different sources [ 9 , 32 , 33 , 34 , 35 , 36 ], displaying complex and conspicuous eye-catching behavioural sequences [ 37 , 38 ]. For example, the ‘pasted’ scent marks of brown hyenas ( Parahyaena brunnea ) comprise two anal gland secretions from sebaceous and apocrine tissues, respectively, deposited within the same sequence scent-marking event [ 39 ].…”