Family Kogiidae - Pygmy and Dwarf Sperm Whale (2 species in 1 genus)
The pygmy and dwarf sperm whales are much smaller and share only a slight resemblance to the great sperm whale. They have blunt squarish heads, with underslung lower jaws (like their larger counterparts), but the head is much smaller than in the sperm whale, and the blowhole is not located at the front of the head as it is in the sperm whale. The skull structure is curious; it shares a basin-like facial area and great asymmetry with the sperm whale, but is much shorter. The dorsal fin in both species is larger than that of the sperm whale. The biology of these animals is very poorly known.
Genus Kogia containing 2 species:
Kogia breviceps (Pygmy sperm whale)
Kogia simus (Dwarf sperm whale)