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.

在鳍足类动物中，很少报道双胞胎幼崽，并且经常与收养案例混淆。在这里，我们报告了对南极洲罗斯海特拉诺瓦湾双威德尔海豹幼崽的直接实地观察。在 2019 年的繁殖期间，观察到一只雌性海豹产下双胞胎幼崽。出生日期记录为11月9日，这是该群体中最晚的出生日期（比第一个饲养员晚40天）。这对双胞胎幼崽与母亲表现出强烈的亲密行为，并在出生后五天吸吮。雌性和幼崽从第 6 天起就消失了，第 12 天在海冰裂缝附近发现其中一只双胞胎幼崽死亡。在这里，我们提供了双胞胎从出生到死亡的详细实地观察。