Three cases of potential twinning in Weddell seals (Leptonychotes weddellii) at Fildes Peninsula, King George Island, Antarctica
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An isolated female with two pups in the field has occasionally been documented in pinnipeds; this phenomenon may represent twinning, fostering, or adoption. This study presents three cases of female Weddell seals (Leptonychotes weddellii) that attended two pups on Biyu Beach at Fildes Peninsula, King George Island, Antarctica where 16 mother–pup pairs were observed in total during the 2014 breeding season. Each pup in each case exhibited intense association with the female, despite being separated on occasions from the mother. In each case, both pups, at about 3 weeks of age, showed different growth development, which corresponded to the duration of nursing from their mothers; the bigger pup had more opportunity to suckle. Moreover, both pups in each case were female, were born in a low-density colony, and had strong attachment with their mother, showing similarities to other studies of confirmed twinning in pinnipeds. All individuals were in good condition when last seen, which could be due to the possible suitable rearing environment, e.g., low-density colony and flat beach topography.
KeywordsAdoption Behavior Fildes Peninsula Fostering Weddell seal Twinning
The authors are grateful to the Chinese Arctic and Antarctic Administration of the State Oceanic Administration, and the Polar Research Institute of China for logistical support in the field. We also appreciate the members J. J. Cao, J. Xiong, and R. H. Wang of the 30th Chinese Antarctic scientific expedition for their generous help and assistance during field investigation, and the anonymous reviewers for their comments to improve this paper. This research was funded by the Scientific Research Foundation of the Third Institute of Oceanography, State Oceanic Administration of China (TIO2015036), Chinese Polar Environment Comprehensive Investigation and Assessment Program (CHINARE2012-2015-04-03, CHINARE2012-2015-03-05), and State Oceanic Administration of China (SOA, 2011GW13ZS07019).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflicts of interest.
All applicable international, national, and/or institutional guidelines for the care and use of animals were followed.
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