Development of intra- and interspecific chemical communication

The infant, the adult, the aged person, each has is own kind of smell, and... it might be possible, within certain limits, to discover the age of a person by his odor. In both sexes puberty, adolescence, early manhood and womanhood are marked by a gradual development of the adult odor of skin and excreta, in general harmony with the secondary sexual developments of hair and pigment. 

The nature-nurture problem revisited in most vertebrates, early experience of certain odors, interwoven with genetically anchored developmental processes, produces lasting, often irreversible odor recognition, preferences, or avoidance. Such behavioral development often occurs during more or less defined critical windows in time. The development of responses to odors often precedes that of odor production. Neonates already orient towards odors, while many pheromones are not produced until adulthood. Even before hatching or birth, the journey of chemical communication starts in the egg or the uterus. Knowing how chemical communication and chemosensoiy responses to food or danger develop is essential in areas such as animal husbandry or human behavior. 

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