I have read accounts of these attacks that show the orcas have a specific pattern for conducting them. This pattern involves the attacking orca striking the great white shark in its midbody with a heavy blow using their snout. The stunned shark is then rolled on to its back to induce the well-known trance effect that this maneuver has on sharks. The orca is them free to predate at will on the stunned and unresisting shark’s liver.
However, the accounts I have read and the YouTube videos I’ve seen limit this behavior to a multigeneration orca family group migrating up and down the west coast of North and Central America. It appears to be a learned behavior for the orcas. That would fit their mammalian heritage, family living, and general high intelligence. The fact that they have the technique “down cold,” so to speak, would seem to indicate they have been developing and refining it for awhile.
How long? Long enough for the cold blooded, generally solitary, dangerous predatory fish they are hunting to develop a hard wired behavioral response to some indication that orcas are in the area. That is the work of generations upon generations.
What is the trigger? My bet is the trigger for the response to flee the area is hearing orca-specific vocalizations and maybe feeling the sound/pressure wave from the midbody attacks if the attack is immediately nearby. An interesting expansion of the research might be to see if Great White Sharks in completely different locations have the same responses to hearing orcas nearby. Say playback recordings of the orcas and orca attacks to sharks schooling to feed on seals off of Cape Town in South Africa?
How they react could be very interesting.
Captain Tom,
Apologies for my ignorance concerning the orcas off of Cape Town. I hadn’t come across that reporting. However, it does support the idea that orcas have been feeding on Great Whites long enough for the flight response to become embedded in their behavior.
That’s a long time for a fish.