Licking of the Neonate and Duration of Labor in Great Apes and Man

An hypothesis recently advanced by Montagu relates the cutaneous stimulation of prolonged labor in great apes and man to the proper functioning of the newborn. These exceptional primates, according to Montagu, do not therefore stimulate the newborn by licking, as is the case for mammals in which labor is of short duration. Though man is believed to differ from other primates, especially the apes, in duration and difficulty of labor, we present data to show that the case at present rests on unstandardized measures of durations and on incomplete anatomical arguments. Until more objective criteria for charting the progress of labor are developed, there is no way of knowing if the assumption of a significant difference is correct. In any case, there seems to be no valid basis for linking differences in labor among primates with different forms of postpartum care, of which licking is but one example.