The characteristics distinguishing the species from the killer whale are tabularized on p. [84]; its differences from the pilot whales are summarized on p. [92].
At sea, false killer whales are distinguishable from the other two species primarily by their larger size and differences in coloration. False killer whales are up to 18 feet (5.5 m) in length. Pygmy killer whales and many-toothed blackfish reach only 8-9 feet (2.4-2.7 m) in length. Pygmy killer whales have an extensive region of white on the belly which may extend onto the sides and both pygmy killer whales and many-toothed blackfish have a distinctive white region on the lips, usually lacking or indistinct on false killer whales.
Neither of the smaller species of blackfish has been reported to ride bow waves.
Distribution
False killer whales are widely distributed in the pelagic tropical, subtropical, and warm temperate waters of the western North Atlantic. They have been reported from off Maryland south along the mainland coasts of North America, in the Gulf of Mexico from Cuba and the Lesser Antilles, and from the southeast Caribbean Sea. The species has been reported from Venezuela.
Stranded Specimens
Stranded false killer whales can be positively identified by: 1) the large size (to 18 feet [5.5 m]); 2) the slender body tapering rapidly to a long slender head; 3) the markedly long mouth, with from 8 to 11 large, conspicuous teeth in each side of each jaw recalling those of the killer whale, but circular and not, as in killer whales, elliptical; 4) the unusually shaped flipper bulging conspicuously on the forward margin.
For comparison with "blackfish" of similar size (the pilot whales) see p. [92] and [94].
False killer whales do not appear to occur frequently in coastal waters, sandy bays, or estuaries, though entire herds have stranded in such areas. Records from throughout the range suggest that the species has an oceanic distribution.