Publishing their results in the journal PLOS ONE, Mr McInnes found patterns in behaviour of outer-coast transients that differed from those of their inner-coast cousins.
While " inner-coast" transients stalk shallow waters near the shore, " outer-coast" transients hunt in the deep open waters along canyons at the edge of the continental shelf.
Outer-coast transients appear to have developed specialised strategies-such as the repeated battering and drowning of grey whale calves-because their prey is bigger and takes more time to subdue.
While studying the outer-coast transients, Mr McInnes also stumbled upon hints of a previously undescribed population of killer whales that were big-game hunters of an entirely different class.
They are strangers in their birthplace, and the leafy lanes they have known from childhood or the populous streets in which they have played, remain but a place of passage.