Feresa attenuata - The Pygmy Killer Whale

As you can see, the attenuata looks a lot like other dolphins and could easily be confused with the melon-headed whale. They a relatively small whales, growing up to 6.5 metres, they share a number of qualities with the orca (hence the common name), including their propensity to attack and kill other cetaceans (usually dolphins). Their diet mainly consists of small fish and cephalopods. They are very rare and until the 1950s had only been identified by a pair of skull specimens.

Performing tricks in captivity

 They have occasionally been caught and kept in captivity, where they can behave aggressively towards their captors. There are some behaviours which distinguish them from false killer whales, including their sluggishness (they tend not to move very quickly at the surface if they don't have to), and their lack of interest in humans. False killer whales will often wake-surf, that is, they will swim along at speed in the wake of a boat, whereas this behaviour is not seen in pygmy killer whales.

Attenuate specimen
Shimonoseki Marine Science Museum
Japan

As with many cetaceans, population estimates are difficult, and they are seldom seen. There is a resident group off Hawaii, but even these make up for a tiny amount of cetacean sightings in the area. To see a film of attenuata frolicking, click here and here.