A distinct subpopulation of orca whales appears to be using specialized hunting techniques to hunt the marine mammals that they eat. Orca–or killer whales–are the ultimate apex predators, who have been observed attacking great white sharks, porpoises, and even blue whales. They are found in every ocean on the planet, and the specific environments that they live in have largely shaped their particular food preferences. The killer whales that forage near the deep submarine canyons off the California coast may use the sloping seascape to inform the ways that they catch food. These findings are described in a study published March 20 in the open-access journal PLOS ONE.
Residents vs. transients
Groups of orca whales can form different populations or ecotypes. They have their own social structures, food preferences, and hunting techniques. Resident killer whales, like the three endangered pods that spend the summer and fall months in and around Puget Sound near Seattle, Washington exclusively eat salmon and have a more round dorsal fin.
[Related: Orca observed hunting and killing a great white shark by itself for the first time.]
The other type of killer whales called transient killer whales specialize in hunting marine mammals. Transients are typically slightly larger than resident orcas have a more pointed dorsal fin.
The transients that forage in the Northern Pacific Ocean can also be further divided into two groups. The inner coast whales feed in shallow coastal waters, while outer coast whales hunt in deeper water. Most studies have focused on the orcas that hunt closer to shore and not much is known about the foraging techniques for the more offshore whales, such as those near the Monterey Submarine Canyon in California.
“Monterey Bay provides a conducive environment to investigate transient foraging ecology and behavior, due to it having a large deep submarine canyon system occurring close to shore that is accessible to…
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