Boran, James

Heimlich, Sara

Pilot whales are distributed worldwide with two species, the cold-water long-finned pilot whale, Globicephala melas, and the warm-water short-finned pilot whale, G. macrorhynchus. Long-finned pilot whales have an anti-tropical distribution in separated northern and southern hemisphere groupings, with the North Pacific group extinct, while short-finned pilot whales occur in all tropical oceans. These two species exhibit different life history patterns, with long-finned pilot whales maturing faster and reproducing up to the end of life and dying sooner, while short-finned pilot whales have long maturation (esp. for males) and a post-reproductive phase where females live up to 30 years beyond the birth of their last calf. Photo-identification studies of short-finned pilot whales in Macaronesia (the Canary Islands, Azores, and Madeira) show long-term relationships maintained over hundreds of kilometers and exhibit a wide variety of site fidelity patterns. Mixing between core residents and visiting transients in high productivity areas suggest more fluid interactions than those observed for resident ecotype killer whales or orca (Orcinus orca) that maintain isolated groups from other, co-occurring ecotypes. Four features of orca matrilineal society, (1) matrilineal associations between females, (2) male natal philopatry, (3) extra-group mating or natal exogamy, and (4) post-reproductive lifespan, are compared with short-finned pilot whales, and we conclude that pilot whale societies have numerous matrilineal features, albeit less specialized than those exhibited by orca. Divergent prey preferences most likely account for these differences

Pilot whales:delphinid matriarchies in deep seas

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