Allo-suckling occurrence and its effect on lactation and nursing duration in harbour seals ( Phoca vitulina ) in Orkney, Scotland

Fostering and allo-suckling are widespread among pinnipeds, and several hypotheses have been formulated to explain their occurrence. Here, we describe the occurrence of allo-suckling in harbour seals from photo-identification data of females and pups in Orkney (Scotland) during the pupping seasons b...

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Bibliographic Details
Published in:Behavioral Ecology and Sociobiology
Main Authors: Arso Civil, Monica, Hague, Emily, Langley, Izzy, Scott-Hayward, Lindesay
Format: Article in Journal/Newspaper
Language:English
Published: 2021
Subjects:
Online Access:https://research-portal.st-andrews.ac.uk/en/publications/55fb1577-60f0-4b2b-b518-94cbc108ad61
https://doi.org/10.1007/s00265-021-03051-y
https://research-repository.st-andrews.ac.uk/bitstream/10023/23793/1/ArsoCivil_2021_BES_Allo_suckling_CC.pdf
Description
Summary:Fostering and allo-suckling are widespread among pinnipeds, and several hypotheses have been formulated to explain their occurrence. Here, we describe the occurrence of allo-suckling in harbour seals from photo-identification data of females and pups in Orkney (Scotland) during the pupping seasons between 2016 and 2019. We used a generalised linear model framework to investigate the effect of allo-suckling on the duration of lactation (females) and of nursing period (pups). A generalised additive model framework was used to explore how the probability of allo-suckling varied throughout the pupping season, and with changes in mother-pup separation time. Allo-suckling was observed in 31 females, at higher rates (18–37% of lactating females and 18–47% of the pups every year) than those observed in other phocid populations, with 13 females allo-suckling in multiple years. The duration of the pups’ nursing period was not affected by allo-suckling occurrence. However, females in mother-pup pairs where both mother and pup allo-suckled had longer lactation duration than when only the pup allo-suckled, or than in pairs where no allo-suckling was observed. The probability of allo-suckling increased during the pupping season and with increased mother-pup separation time. However, the proximate causes and the consequences on future reproductive output and pup survival remain unknown.