Lip-Licking Behavior in Captive Musk Shrews, Suncus Murinus

Authors: Stine, C.J.¹; Dryden, G.L.²

Source: Behaviour, Volume 62, Numbers 3-4, 1977 , pp. 298-313(16)

Publisher: BRILL

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Abstract:

Newborn Suncus murinus deliberately approach their mother's mouth immediately after nursing (92% of 99 occurrences). The mother is receptive to 93% of these approaches and the young licks her lower lip anterior to her incisors for a mean of 1 minute, 9 seconds. Youngest shrews both nurse and approach the mother's mouth in a ventrum-up position. As they gain motor capabilities, they nurse dorsum-up and lip-lick in this position, progressively following the mother's head through a vertical arc. By day 18, when lip-licking was last observed, the mother's head may be 120° or more from horizontal. Lip-licking is most frequent in young animals, decreasing toward weaning. Lip-licking bouts are terminated either by the mother retracting her head or by the young withdrawing from the level of her mouth. Young shrews frequently, but not always, climb on their mother's back after lip-licking and rest there by draping at right angles to her body. As they mature, they drape longitudinally on her. Draping persists into adulthood and may be involved in social marking. The functions of lip-licking are unknown. Mothers apparently do not regurgitate prior to or during the act but the deliberateness, intensity, and site specificity of lip-licking suggest that saliva may be transferred to the young. Indirect evidence raises the possibility that, among other functions, lip-licking may serve to provide the offspring with maternal digestlive enzymes. This is being investigated.

Document Type: Research article

DOI: http://dx.doi.org/10.1163/156853977X00153

Affiliations: 1: Laboratory of comparative behavior, Johns Hopkins University, Baltimore, Maryland 2: Biology Department, Slippery Rock State College, Slippery Rock, Pennsylvania, U.S.A.

Publication date: 1977-01-01