False killer whales are black or dark gray with a white blaze on their ventral side. Some have a paler gray coloring on their head and sides. Their heads are rounded and often described as blunt and conical with a melon-shaped forehead. Their bodies are elongated. The dorsal fin is sickle-shaped and protrudes from the middle of their back, the pectoral flippers are pointed. They have a slight overbite--the upper jaw extends beyond the lower jaw. This gives them a slight beaked look to their rostrum. No subspecies have been described.
Adult males range from 3.7 to 6.1 m in length, while adult females range from 3.5 to 5 m. Adults may weigh 917 to 1842 kg. Newborns range from 1.5 to 1.9 m in length and weigh about 80 kg. The dorsal fin can grow to be 18 to 40 cm high. This species has a more slender build compared to other dolphins and they have tapering heads and flippers. Their flippers average about one-tenth of the head and body length and have a distinct hump on the leading margin of the fin. There is a definite median notch on their flukes and they are very thin with pointed tips. False killer whales also have 8 to 11 teeth on each side of their jaw.
The skulls of females range in length from 55 to 59 cm, while males are 58 to 65 cm. They have 47 to 52 vertebrae: 7 cervical, 10 thoracic, 11 lumbar, and 20 to 23 caudal vertebrae. They have 10 pairs of ribs. Their manus consists of 6 carpals, 5 metacarpals, and 14 phalanges.
This species is often mistaken for bottlenose dolphins (Tursiops truncatus), short-finned pilot whales (Globicephala macrorhynchus), or long-finned pilot whales (Globicephala melas) as they inhabit the same regions. To distinguish these species, bottlenose dolphins have beaks, and pilot whales are larger with obvious dorsal fin differences.
Range mass: 916.26 to 1841.59 kg.
Range length: 3.5 to 6.1 m.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: male larger; sexes shaped differently