LITTLE is known of the chemistry of odour in higher animals1–4 in relation to the importance which behavioural studies have ascribed to it5–7. Those chemical studies which have been undertaken have often lacked a concern for the behavioural and ecological implications of odour, although exceptions to this rule are becoming more numerous2,8,9. Here we describe preliminary chemical studies on the nature of the anal gland secretion of the red fox (Vulpes vulpes fulva, L.). An account of related behavioural studies will appear shortly10. Further chemical studies on the nature, variability and significance of the volatile components of the anal gland secretion of the red fox and of other Canidae are in progress. Microbiological studies are also planned11.