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Antarctica-111123-592 | by Kelly Cheng
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Antarctica-111123-592

Orcas, commonly referred to as “killer whales” and “wolves of the sea,” are noted for their pack-like hunting techniques that demonstrate intelligence and cunning with spectacular displays. They are a locally common sight in the Southern Ocean and often spotted during Antarctica cruises. Globally they have been known to feed on seals, fishes, squid, seabirds (including penguins) and other whale species, making the coastal zone of Antarctica a prime hunting ground.

 

Known as Orcinus orca in scientific literature and sometimes called simply orca, the largest members of the dolphin family are immediately distinguishable by their black and white pattern and by their size.

 

One of the most obvious characteristics that aids in the determination of whether or not one is seeing a male or a female is the shape of the dorsal fin, a field mark easily discernible from a ship. Male dorsals can be up to six feet long, one-fifth of their overall length, and are tall and erect. Female and juvenile dorsals tend to be falcate (curved back) and usually do not exceed three feet. The underside of the tail fluke is white. Characteristics used to identify individuals include variations of the dorsal fin, the eyepatch—a white spot of varying shape and orientation behind their eye, and the presence and/or shape of a dorsal cape. They have a fine, bushy, conspicuous blow that frequently signals their presence.

 

Exciting to watch, orcas have a behavioral repertoire seemingly made for shipboard viewing. Breaching—involving graceful leaps completely out of the water with thrilling re-entries, tail-slapping, spy-hopping and logging—whereby the entire group faces in the same direction in close proximity to each other—offer numerous opportunities to observe these striking animals in their environment.

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Taken on November 23, 2011