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Follow SWFSC scientists currently in the field, January 2012
Ecology of Antarctic Killer Whales
The killer whale
) is the top marine predator and perhaps the most widespread vertebrate on earth, occurring in all the world’s oceans. Although currently considered to be a single species worldwide, our research in Antarctic waters has revealed that there are at least 4 distinctly different-looking forms of killer whales, referred to as types A, B, C and D. Little is known about Type D
which is infrequently seen in inaccessible subantarctic waters, but the other forms appear to represent different “ecotypes” that occur sympatrically in Antarctica, with distinct prey specialization on minke whales, ice seals and fish, respectively. Our recent genetic work suggests that these may represent at least three different species.
The role of killer whales in Antarctic marine ecosystems will depend on their respective population sizes, their seasonal movements in and out of Antarctic waters, and the amount and types of prey that they consume. Our current research in Antarctica consists of satellite-tagging killer whales
to study movements
, boat-based focal follows to observe feeding behaviors and prey preferences
, collecting tissue biopsy samples to compare dietary signals, contaminant loads and genetic differences, and compiling a photo-identification database estimate population sizes and residency patterns of different ecotypes from different areas. (Contact Robert L. Pitman
and John W. Durban
We collaborate our research and public outreach efforts in Antarctica with the National Geographic Society and Lindblad Expeditions. This collaboration is featured in this video , along with a demonstration of how satellite tags are deployed on killer whales to assist in tracking movements.
Antarctic killer whales make rapid, round-trip movements to subtropical waters: evidence for physiological maintenance migrations? - John W. Durban and Robert L. Pitman
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Example of the rapid migration of a type B killer whale from the Antarctic Peninsula to the edge of the tropics and back, in just 42 days. Durban and Pitman 2011
Killer whales are important marine predators at high latitudes, but the extent of their movements is poorly understood. We used satellite tags to provide the first evidence of migration for this species: type B killer whales tagged when foraging near the Antarctic Peninsula undertook rapid movements to warm sub-tropical waters off Uruguay and Brazil; including a non-stop round trip of almost 9400km(5075nm) in just 42 days. We suggest that these movements may represent periodic maintenance migrations, with warmer waters allowing skin regeneration without the high cost of heat loss: a possible factor in the migration of other whales also.
Cooperative hunting behavior, prey selectivity and prey handling by pack ice killer whales (Orcinus orca), type B, in Antarctic Peninsula waters - Robert L. Pitman and John W. Durban
Herein, we report on our observations of "pack ice" killer whales hunting off the west coast of the Antarctic peninsula during January 2009. They hunted almost exclusively by wave-washing seals off ice floes, which provided us with a unique opportunity to study cooperative hunting behavior and prey choice by a mammal-eating killer whale. In addition to providing new details on wave-wash hunting behavior, we also describe and discuss our observations on prey selectivity and postmortem prey handling by this little-known killer whale.
Durban, J.W., and R. L. Pitman. 2011. Antarctic killer whales make rapid, round-trip movements to subtropical waters: evidence for physiological maintenance migrations? Biol. Lett. (doi: 10.1098/rsbl.2011.0875).
Pitman, R. L. and J. W. Durban. 2011. Cooperative hunting behavior, prey selectivity and prey handling by pack ice killer whales (Orcinus orca), type B, in Antarctic Peninsula waters. Marine Mammal Science. (doi: 10.1111/j.1748-7692.2010.00453.x).
Morin, P., Archer, F., Foote, A., Vilstrup, J., Allen, E., Wade, P., Durban, J., Parsons, K., Pitman, R., Li, L. 2010 Complete mitochondrial genome phylogeographic analysis of killer whales (Orcinus orca) indicates multiple species. Genome research. 20, 908.
Foote, A. D., Morin, P. A., Durban, J. W., Pitman, R. L., Wade, P., Willerslev, E., Gilbert, M. T. P., da Fonseca, R. R. 2011 Positive selection on the killer whale mitogenome. Biol. Lett. 7, 116.
Pitman, R., Durban, J. 2010. Killer whale predation on penguins in Antarctica. Polar Biology 33:1589-1594. doi: 10.1007/s00300-010-0853-5.
Pitman, R., Durban, J., Greenfelder, M., Guinet, C., Jorgensen, M., Olson, P., Plana, J., Tixier, P., Towers, J. 2010. Observations of a distinctive morphotype of killer whale (Orcinus orca), type D, from subantarctic waters. Polar Biology 34:303-306. doi: 10.1007/s00300-010-0871-3.
Morin, P. A., F. I. Archer, A. D. Foote, M. Thomas, P. Gilbert, E. E. Allen, P. Wade, J. Durban, K. Parsons, R. Pitman, L. Li, P. Bouffard, J. Vilstrup, S. A. Nielsen, E. Willerslev and T. Harkins. 2010. Complete mitochondrial genome analysis of killer whales (Orcinus orca) indicates multiple species. Genome Research 20:908-916.
Pitman, R. L., and J. W. Durban. 2009. Save the seal! Natural History Magazine Nov 2009:48.
Pitman, R.L. 2008. Killer snowballs. Natural History December 2008/January 2009:56.
Andrews, R.D., R.L. Pitman and L.T. Ballance. 2008. Satellite tracking reveals distinct movement patterns for Type B and Type C killer whales in the southern Ross Sea, Antarctica. Polar Biology 31:1461-1468.
Krahn, M.M., R.L. Pitman, D.G. Burrows, D.P. Herman, and R.W. Pearce. 2008. Use of chemical tracers to assess diet and persistent organic pollutants in Antarctic Type C killer whales. Marine Mammal Science 24(3):643-663.
LeDuc, R.G., K.M. Robertson, and R.L. Pitman. 2008. Mitochondrial sequence divergence among Antarctic killer whale ecotypes is consistent with multiple species. Biol. Lett. 4:426-429.
Pitman, R.L., W.L. Perryman, D. LeRoi, and E. Eilers. 2007. A dwarf form of killer whale in Antarctica. Journal of Mammalogy 88(1):43-48.
Pitman, R.L. 2006. Killer Whale. Pages 570-572 in: Encyclopedia of the Antarctic, Beau Riffenburgh (ed.), Routledge: New York.
Pitman, R.L. 2003. Good whale hunting. Natural History December 2003/January 2004: 24-28.
Pitman, R.L. and P. Ensor. 2003. Three forms of kiler whales in Antarctic waters. Journal of Cetacean Research and Managment 5(2): 131-139.