Testing smell when it is really vital: behavioral assays of social odors in the neonatal mouse.

The initial interactions of mouse newborns with their mother are crucial for their survival. These interactions rapidly end in the pups reaching nipples and getting milk. While we realize that olfaction is clearly prevailing in the success of these first suckling episodes, we still understand little about the nature and range of the natural odorants involved. Here we non-exhaustively describe some experimental principles and methods to assay the behavior of newly born and infant mice exposed to different odor stimuli from conspecifics. Testing neonatal and young mice with chemostimuli which they are evolutionarily or developmentally canalized to detect may be a productive way to trace unanticipated odor signals. Moreover, testing neonates also may also lead to characterize unsuspected strategies of murine females to produce and release odor messages.