RETRACTED ARTICLE: Field observations of Weddell seal (Leptonychotes weddellii) twins at Terra Nova Bay in the Ross Sea, Antarctica

In pinnipeds, twin pups are rarely reported and are often confused with cases of adoption. Here, we report the direct field observations of twin Weddell seal pups at Terra Nova Bay in the Ross Sea, Antarctica. During the breeding period in 2019, a female seal was observed giving birth to twin pups. The date of birth was recorded as 9th November, which was the latest birthing date in the colony (40 days later than the first breeder). The twin pups exhibited strong bonding behavior with their mother and sucked for five days after the birth. The female and pups had disappeared since day 6 and one of the twin pups was found dead near a sea-ice crack on day 12. Here we provide the detailed field observations of the twins from birth to death. We discuss that the high costs of the late breeding and lactation associated with twins could prevent seal twins from surviving.