Data Sheet 1_Novel evidence of interaction between killer whales (Orcinus orca) and juvenile white sharks (Carcharodon carcharias) in the Gulf of California, Mexico.docx

White sharks (Carcharodon carcharias), have only one known natural predator in the ocean, the orca or killer whale (Orcinus orca). While interactions between these coexisting apex predators are known to occur, killer whales are adept at subduing adult white sharks and consuming their energy-rich livers. White sharks in turn are highly responsive to the appearance of killer whales and will vacate habitual feeding aggregations en masse to avoid predation. To date, interactions between killer whales and juvenile white sharks (~2.5 m TL) have been reported in South Africa, while the literature reports that these interactions occur primarily with larger white sharks, which naturally have a larger liver, and potentially compete with killer whales for pinniped prey. Here we document novel repeated predations by killer whales on juvenile white sharks in the Gulf of California. Aerial videos indicate consistency in killer whales’ repeated assaults and strikes on the sharks, indicating efficient ability by the mammals in attempting to induce tonic immobility in the prey and allow uninterrupted access to the liver for consumption. Once extirpated from the prey body, the target organ is shared between the members of the pods including calves. Images analysis of the killer whales involved in the attacks confirms previous observations of an existent pod possibly specialized in hunting elasmobranchs in this region.