A comparison of pigmentation features among North Atlantic killer whale (Orcinus orca) populations

Here we present a comparison of saddle and eye patch patterns of killer whales from Norwegian, Icelandic, British, Spanishand Greenlandic waters. We found only a small amount of variation in saddle patch shapes, which may reflect a recent phylo-genetic divergence from the most recent common ancestor. Eye patch shapes were more variable than saddle patches in smalldetails. Most individuals had eye patches with parallel orientation, with the exception of a small group of killer whales fromthe Hebrides, which, as previously reported, had sloping eye patches that sloped downward at the posterior end. This differ-entiation in pigmentation patterns of the Hebridean killer whales from neighbouring populations could reflect one or moreof several evolutionary processes, including a deeper phylogenetic divergence, low gene flow with other local populationsand drift.