Attributes / relations provided by
♦ ¹Delphinapterus leucas, Barbara E. Stewart and Robert E. A. Stewart, MAMMALIAN SPECIES No. 336, pp. 1-8 (1989)
♦ ²Diet composition of polar bears in Svalbard and the western Barents Sea, Andrew E. Derocher, Øystein Wiig, Magnus Andersen, Polar Biol (2002) 25: 448–452
♦ ³Food Web Relationships of Northern Puget Sound and the Strait of Juan de Fuca : a Synthesis of the Available Knowledge, Charles A. Simenstad, Bruce S. Miller, Carl F. Nyblade, Kathleen Thornburgh, and Lewis J. Bledsoe, EPA-600 7-29-259 September 1979
♦ ⁴Alaska Wildlife Notebook Series, Alaska Department of Fish and Game