Stranded pygmy killer whales can be clearly distinguished from both the false killer whale and the many-toothed blackfish. In addition to the differences discussed above, the following are key differences between the pygmy and false killer whales:

Pygmy Killer WhaleFalse Killer Whale
TEETH
10-13 in each side of upperand lower jaws; lower teethsmaller.8-11 per jaw per side,prominent.
VENTRAL COLORATION
White from anus to under tailstock, white may extend upsides.Dark from anus to tail stock;lighter pale gray area forwardbetween flippers.
FLIPPERS
Smoothly rounded.Characteristic hump on forwardmargin.

Pygmy killer whales can be distinguished from many-toothed blackfish on the basis of the second species' larger number of teeth. (Many-toothed blackfish have from 22 to 25 teeth in the upper jaw and from 21 to 24 in the lower jaw.)

Figure 152.—Pygmy killer whales at sea northwest of Hawaii ([top]) off the island of Oahu, Hawaii ([middle]), and from southeastern Florida in the tank at the Wometco Miami Seaquarium ([bottom]). When swimming rapidly, pygmy killer whales may closely resemble the much larger false killer whales. In addition to their much smaller size, rarely exceeding 9 feet (2.7 m), however, pygmy killer whales can be distinguished by their more rounded head, the white coloration of the lips and chin, and the white zone on the belly, sometimes extending up the sides. (Photos by S. Ohsumi [top]; J. Naughton, National Marine Fisheries Service and courtesy of E. Shallenberger, Sea Life Park [middle]; and courtesy of Wometco Miami Seaquarium [bottom].)