Marine biologists from the University of Oregon and the University of New Brunswick have recorded common, previously unknown, ultrasonic vocalizations produced by Weddell seals ( Leptonychotes weddellii), the world’s southernmost-ranging mammal. They’ve identified nine recurrent call types in more than one year (2017-2018) of broadband acoustic data obtained by a continuously recording underwater observatory in McMurdo Sound, Antarctica. Weddell seals ( Leptonychotes weddellii). Image credit: Elliott Devries. Weddell seals are a species of large and relatively abundant true seals in the family Phocidae. They have a circumpolar distribution around Antarctica, including the highest-latitude coastal regions. In contrast to the other Antarctic seals, they prefer expanses of heavy pack ice or thick shore-fast sea ice, using their teeth to maintain access holes in the ice.