Introduction

As we are mammals, it is highly likely that many behavioural and physiological aspects of human biology are influenced by pheromones. However, only recently has the importance of chemical cues for humans become clear, so I start by investigating the evidence that odours are important for humans. I then look at how these natural odours are produced and perceived. Human responses to perfumes and artificial scents would form a book on their own (see further reading).

Humans are just one of some 200 living species of primate (Dixson 1998). While we and our nearest relatives, the great apes (the gorillas, orang-utans, bonobos and chimpanzees), may not use odour communication in quite the same ways as the Old World and New World monkeys, chemical communication is still important to us (Fig. 13.1) (Table 13.1). Unlike other primates, humans and great apes have axillary (armpit) scent glands. In terms of numbers and sizes of sebaceous and apocrine glands (see Box 13.1), humans have to be considered the most highly scented ape of all (Stoddart 1990). These scent glands give off a plethora of natural products that envelope the body with a complex, and probably individually distinctive, volatile label (Schaal & Porter 1991).

Olfaction is the suppressed sense in contemporary Western society. We give it the least attention and seem to value it the least of our senses. However, its importance is felt when lost. Oliver Sacks quotes a man who lost his sense of smell after a head injury: ‘when I lost [my sense of smell] it was like being struck blind. Life lost a good deal of its savor – one doesn't realise how much ‘savor’ is smell.