Filmmaker Edwar Herreño captured this amazing footage of six killer whales surrounding and immobilizing a 3 meter tiger shark last week off Cocos Island National Park, 300 km west of Costa Rica. They turned it upside down, initiating a state on tonic immobility that rendered the shark unresponsive and helpless. We have witnessed this technique use by orcas from a shark-eating culture in several places around the globe, including New Zealand, the Pacific Northwest, Mexico, and right here in California - including Newport Beach (1988) and the Farallon Islands (1997), both by the LA Pod, in Monterey Bay (1999) by offshore type killer whales. This is a fascinating example of group cooperation by members of an experienced shark-killing culture! Here is a video about that 1997 attack on a great white shark, with research relating to tonic immobility: The Whale That Ate Jaws. https://youtube/watch?v=Ct3f7iWGwcQ There have only been about 8 killer whale sightings off Costa Rica; little is known about how many utilize these waters, or about their dietary preferences. Orcas in the Atlantic Ocean have not been separated into our familiar transient (mammal-eaters), resident (fish-eaters), and offshore (shark-eaters) ecotypes that specialize in certain prey. In the Atlantic Ocean, some eat fish, others marine mammals, still others eat both. Killer whales in the Atlantic Ocean may be in the beginning of the speciation process that is more refined in the Pacific Northwest in in Antarctic waters, where orcas have existed for a much longer time. The eastern North Atlantic Ocean was under ice just 10,000 years ago, so most orcas there havent had as much time to differentiate as they have in the North Pacific and Antarctic. Here is an interesting reference about North Atlantic killer whale research: news.sciencemag.org/evolution/2013/08/north-atlantic-killer-whales-may-be-branching-two-species inquisitr/1469902/killer-whales-hunt-down-and-attack-tiger-shark-in-costa-rica/
Posted on: Sat, 13 Sep 2014 16:21:13 +0000
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