Early pupping of a sub-Antarctic fur seal at Inaccessible Island, Tristan da Cunha

Abstract

A sub-Antarctic fur seal, Arctocephalus tropicalis, pup was located on Inaccessible Island in the Tristan da Cunha archipelago (TdC), well before the start of the annual breeding (pupping and mating) season in 2018. It was born a few days before 27 September 2018, at least 59 days before the next pup was observed on the island in 2018 and 75 days before the median birthdate for the species at the TdC. A malfunctioning of the obligate delay of implantation of the blastocyst in its mother was likely the cause of the early birth.