The killer whale’s unique cooperative hunting behavior probably evolved in response to their prey’s natural defenses. Since killer whale’s can easily outstrip most pinnipeds (seals) in the water, the pinniped’s natural response is to leave the water, seeking shelter outside the whale’s natural reach (Smith et. al, 1981). In response, killer whales learned to work together to capture prey capable of leaving the water. This is the most likely origin of the self-stranding and wave-washing behaviors (Smith et. al, 1981).

Fig 1. Orca skull.

Since killer whales are apex predators, they are, “capable of adapting their behavior (both social and hunting) to prey species availability” (De Bruyn et. al., 2013). Because of this, hunting behavior appears to evolve differently in different types of killer whales. Behavioral observations report that pack ice (PI) whales capture seals using hunting behaviors entirely different from the tail-slapping or head-butting techniques of the mammal-hunting transient type whales in the north pacific. Reports go on to speculate that, “It may be that hunting different pinniped species requires different tactics, or it could also be that pinniped hunting evolved independently and divergently within these two killer whale lineages” (Pitman & Durban, 2012).

In addition to phylogenetic behavioral differences from habitat, some scientists speculate that killer whales may evolve different hunting behaviors on the familial level. Among the overall population of toothed whales, “killer whales especially appear to remain in distinct pods which are probably family groups. The development of successful cooperative hunting procedures, once learned by the group, must remain as an important part of their behavioral repertoire” (Smith et. al, 1981). Within these family pods, it is entirely possible that whales will evolve hunting behaviors different from those of other pods, which would remain in the same family group for generations, perpetuating hunting behavior unique to one whale family, regardless of species or environment (Smith et. al, 1981).

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