West Coast transient killer whales have long fascinated marine scientists with their impressive mammal-hunting techniques. Now, new research by the University of British Columbia (UBC) is shedding more light on these large ocean predators, confirming them to be two distinct subpopulations: inner and outer coast transients.<\/p>\n
Analysing 16 years of data covering more than 2,200 killer whale encounters, the study, published in PLOS One, reveals that these two groups are split along an east\u2013west divide and rarely mix.<\/p>\n
\u201cI’ve been thinking about this possibility for 15 years,\u201d says first author of the study Josh McInnes from UBC\u2019s Institute for the Oceans and Fisheries (IOF).<\/p>\n
\u201cNow our findings show the West Coast transients are two distinct groups. They eat different things, hunt in different areas and very rarely spend time with each other.\u201d<\/p>\n
West Coast transient killer whales are one of six populations of transient killer whales worldwide. Found from south-eastern Alaska to southern California, the group was previously thought to be split in a north-south divide, but the new research confirms a distinct east\u2013west (or inner\u2013outer) divide.<\/p>\n
Photos from scientific surveys and public sightings allowed the research team to identify individual whales and reveal which animals regularly spend time together. \u201cWe essentially drew friendship maps,\u201d says co-author Dr Andrew Trites, \u201cand then looked at where they were seen to figure out if they hung out in specific neighbourhoods.\u201d<\/p>\n