Pheromones for newborns
Résumé
Newly born mammals have to reach the source of milk as promptly as possible to ensure uninterrupted mother-to-offspring transfer of hydration, nutrients, and energy. Colostrum and milk intake also warrants the neonates' immediate exposure to micronutrients and antioxidants, passive immunization, innocuous bacterial strains, growth factors, and a range of bioactive peptides that control conservative behavioral functions (i.e., antinociception, sleep induction, learning). With these matters and commodities, mothers also pass on to their offspring different levels of chemosensory information that reveal her identity, the location of the mammae, and the composition of milk. Thus, lactation and sucking uniquely coevolved by mammalian females and newborns imply a puzzle of morphological, physiological, and behavioral arrangements (milk gland structure and location; lactational performance, nursing acceptance; neonate's oral competence, absorptive abilities and development) that are all subject to natural selection.