Physeteroidea

Physeteroidea is a superfamily that includes three extant species of whales: the sperm whale, in the genus Physeter, and the pygmy sperm whale and dwarf sperm whale, in the genus Kogia. In the past, these genera have sometimes been united in a single family, the Physeteridae, with the two Kogia species in the subfamily Kogiinae; however, recent practice is to allocate the genus Kogia to its own family, the Kogiidae, leaving the Physeteridae as a monotypic (single extant species) family, although additional fossil representatives of both families are known.

== Characteristics == thumb|Sperm whale and bottlenose whale The sperm whale (Physeter macrocephalus) is the largest species of toothed whale, with adult bulls (males) growing to be about long, and weighing about . The two kogiid species are much smaller, around in length, and weighing .