killer whale or orca Orcinus orca

The killer whale or orca Orcinus orca is found throughout Antarctica and the Antarctic Peninsula and all parts of the Southern Ocean down to the Ross Sea [1,2]. The killer whale can be observed at the pack ice edge and sometimes in dense pack ice and under fast ice [1]. The killer whale usually travels in pods up to thirty individuals which may constitute a stable social structure [1].


The killer whale has a bulky body with a blunt, rounded head, a prominent triangular dorsal fin, and a black and white coloration including a grey saddle patch behind the dorsal fin, a white chin/throat, a broad white lobe reaching up and back beyond its navel, and a white oval patch above and behind its eye [1]. Male killer whales can be up to at least eight meters in length and females one meter shorter [1].


Adult killer whale males have the characteristic tall dorsal fin up to 1.8 meters tall as shown here [1]. In females and juvenile males, it is much smaller and has a concave trailing edge as shown in the top photo above [1]. Female killer whales reach sexual maturity in eight to ten years and males probably over sixteen years [1].

By mid- summer in McMurdo Sound, the plankton bloom reduces underwater visibility dramatically. A hunting mother and calf are seen in an opening lead of ice. Killer whale breeding occurs in autumn and the mother carries the developing baby for 13 to 16 months [1]. Killer whale calves nurse for twelve months and may remain with the mother for as long as ten years [1]. The killer whale preys on fish, cephalopods, and warm-blooded prey like penguins and seals; they have been observed dislodging prey from ice floes by tipping floes up and by swimming past, creating a wave to sweep prey off the floe [1,3]. The killer whale is a fast swimmer and can reach speeds of 46 kilometers/hour (29 miles/hr or 25 knots or 13 meters/sec) or more [1].

Taxonomic note: A supposed new species of dwarf or yellow killer whale was described from the ice edge in Antarctica's Indian Ocean sector [2]. Selecting fish rather than mammals as prey, further studies are needed to establish recognition as a separate species or subspecies [2].

1: FAO Species Identification Sheets for Fishery Purposes : Southern Ocean (Fishing Areas 48, 58 and 88) (CCAMLR Convention Area). W Fischer & JC Hureau, eds. Rome : Food and Agriculture Organization of the United Nations, 1985; 2: Marine Mammals of the World : Systematics and Distribution. DW Rice. Lawrence, Kansas : Society for Marine Mammalogy, 1998; 3: Canadian Journal of Zoology 59(6):1185-1189, 1981

Text ©Peter Brueggeman. Photographs ©Jim Mastro & Norbert Wu. Photographs may not be used in any form without the express written permission of Jim Mastro & Norbert Wu. Norbert Wu no longer grants permission for uncompensated use of his photos under any circumstances whatsoever; want more info?