Sources and chemistry of vertebrate scent

Abstract

The odorous environment of vertebrate animals comprises elements of diverse origins, from those associated with food to those associated with natal nest sites or spawning streams and which act as homing beacons for returning migrants. Each in its own way plays a fundamental and characteristic part in the behavioural ecology of the species, and such odours are just as important as those produced by the individual animal itself for purposes of bringing about and maintaining the social organization of the species. Self-produced odours are aimed almost exclusively at conspecifics (the exceptions to this are those odours produced for defensive purposes) and their production is carefully matched to their dissemination. Vertebrates show a wide range of scent deposition behaviours, each one designed to place the odorous secretion in that part of the environment where it will be most noticed by conspecifics. Most specialized behaviours are derived from behaviours associated with elimination, i.e., urination and defaecation, though the application of scent secretions from some specialized sebaceous glands requires the acquisition of new behaviour patterns. There are many reviews of scent-marking behaviour available, and the reader should consult one of these for details (Ralls, 1971; Johnson, 1973; Stoddart, 1976a). In general, it appears that active scent setting is a mammalian phenomenon; in snakes and lizards scent which is produced by the dorsal and cloacal glands disperses passively as the animals travel through the vegetation.