orcas, or killer whales, were originally called 'whale killers', a name that is extremely apt. orcas have the largest dorsal fin of all cetaceans - roughly the height of a tall man. the white patch behind this fin is as unique as a fingerprint. their white and black patches make them more difficult to spot from above and below, which makes it easier for them to close in on prey (seals, dolphins, penguins, and whales).