Killer Whales (Orcinuis orca) and Dall's Porpoises (Phocoenoides
dalli), have distinct differences.
Geographic variation and sexual dimorphism in the skull of Dall's porpoise, Phocoenoides
Although experienced observers can readily discern the profile differences between a surfacing harbor porpoise and a slow rolling Dali's porpoise (Phocoenoides
dalli), accurate species identification can prove difficult for an inexperienced observer.
(2011), detected that bigger species of porpoises (Phocoenoides
dalli, Phocoena dipotrica) generally show further development of cranial sutures than smaller species (Phocoena phocoena, P spinipinnis), also supporting the hypothesis of Barman et al.
Other marine mammals known to inhabit Cook Inlet, such as killer whales, Orcinus orca; Steller sea lions, harbor porpoise, Phocoena phoconea; and Dali's porpoise, Phocoenoides
dalli, were not observed.
Risso's dolphin (Grampus griseus), Dall's porpoise (Phocoenoides
dalli), Pacific white-sided dolphin (Lagenorhynchus obliquidens), gray whales (Eschrichtius robustus), blue whales (Balaenoptera musculus), minke (Balaenoptera acutorostrata), humpback (Megaptera novaeangliae) whales, fin whales (Balaenoptera physalus), northern right whale dolphins (Lissodelphis borealis) and killer whales (Orcinus orca) were sighted occasionally or during their migrations.
During 1998-2007, "450 harbor and Dall's porpoises (Phocoenoides
dalli) and Pacific white-sided dolphins (Lagenorhynchus obliquidens) along the Pacific Northwest Coast were recovered and subjected to necropsy.
Prey species included Dall's porpoise Phocoenoides
dalli, Pacific white-sided dolphins Lagenoryhncus obliquidens, harbor porpoise Phocoena phocoena, minke whales Balaenoptera acutorostrata, Steller sea lions Eumetopias jubatus and harbor seals Phoca vitulina.
"Dall's porpoises [(Phocoenoides
dalli)], minke whales
The phylogeographic pattern of mitochondrial DNA variation in the Dall's porpoise Phocoenoides
Two other species that are present in the vicinity are the Dall's Porpoise (Phocoenoides
dalli) and Pacific White-sided Dolphin (Lagenorhynchus obliquidens).