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Common mis-understanding of Sharks.
http://en.wikipedia.org/wiki/Killer_whale
Feeding
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Killer whales can induce tonic immobility in sharks and rays by holding them upside down, rendering them helpless and incapable of injuring the whale. Some sharks suffocate within about 15 minutes while the whale holds them still, because these sharks need to move to breathe. In one incident filmed near the Farallon Islands, a female killed a 3–4-metre (9.8–13 ft) long great white shark,[76] apparently after swimming with it upside-down in her mouth and inducing tonic immobility in it. She and another pod member ate the shark's liver and allowed the rest of the carcass to sink.[77]
.... Types
Offshore: A third population of killer whales in the northeast Pacific was discovered in 1988 when humpback whale researcher Jim Darling observed them in open water. As their name suggests, they travel far from shore and feed primarily on schooling fish.[22] However, because of the large scarred and nicked dorsal fins resembling those of mammal-hunting transients, they may also eat mammals and sharks. They have mostly been encountered off the west coast of Vancouver Island and near the Queen Charlotte Islands. Offshores typically congregate in groups of 20–75 with occasional sightings of larger groups of up to 200.[23] Currently, little is known about their habits, but they are genetically distinct from residents and transients. Offshores appear to be smaller than the others, and females are characterized by dorsal fin tips that are continuously rounded.[19] |
發表於 2011-5-13 08:26
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