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

• Published in: Behavioral Ecology and Sociobiology
• Main Authors: Arso Civil, Monica, Hague, Emily, Langley, Izzy, Scott-Hayward, Lindesay
• Other Authors: University of St Andrews. Sea Mammal Research Unit, University of St Andrews. School of Biology, University of St Andrews. Centre for Research into Ecological & Environmental Modelling
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2021
• Subjects: Allo-suckling; Lactation duration; Nursing period; Phocids; Harbour seal; Non-filial; QH301 Biology; DAS; Scottish Government; QH301; Allo; harbour seal; Phoca vitulina
• Online Access: http://hdl.handle.net/10023/23793; https://doi.org/10.1007/s00265-021-03051-y

This study was funded by Scottish Government (grant number MMSS/002/15). 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. Publisher PDF Peer reviewed