of pinnipeds is that pinnipeds are a diphyletic group and otariids and odobenids are more closely related to bears, and phocids are more closely related to mustelids like weasels. Another hypothesis suggests that pinnipeds are a monophyletic group that descended from a single ancestor. This has been more supported by phylogenetic analysis than the diphylectic hypothesis. One such study suggests that phocids are sister taxa to the common ancestor to both otariids and odobenids. Bearded seals belong to the subfamily Phocinae. This subfamily is thought to have evolved after the subfamily Monachinae. Alternative phylogenies show the bearded seal being most closely related to the ribbon seal or the hooded seal. However, molecular evidence suggests that hooded seals are their close relatives. See also References Further reading U.S. National Marine Fisheries Service bearded seal webpage Heptner, V. G.; Nasimovich, A. A; Bannikov, Andrei Grigorevich; Hoffmann, Robert S, Mammals of the Soviet Union, Volume II, part 3 (1996). Washington, D.C. : Smithsonian Institution Libraries and National Science Foundation External links Recording of the bearded seal's unique "spiralling trill" The sound of the bearded seal Voices in the Sea – Sounds of the Bearded Seal Phocines Pinnipeds of the Arctic Ocean Pinnipeds of Europe Pinnipeds of North America Pinnipeds of Asia Mammals described in 1777 Holarctic fauna