Kogiidae

There is some amount of uncertainty over if Kogiidae belongs in the sperm whale family. Research still suggests a close relationship between Kogiidae and sperm whales using mitochondrial DNA, which supports Kogiidae as part of the sperm whale family. Other phylogenetic research raises further questions over a potential relationship between kogiids and Ziphiidae. Other questions exist regarding the high relatedness in mitochondrial DNA between Platanista and kogiids. Fossil evidence is limited for this family, which potentially limits an understanding of their relationship to other extant cetaceans., Denebola brachycephala (top), and an extinct kogiid, Praekogia cedrosensis (bottom), both from the Late Miocene. ORDER ARTIODACTYLA • Infraorder Cetacea • Parvorder Odontoceti toothed whales • Superfamily Physeteroidea • Family Kogiidae • Genus Kogia • Pygmy sperm whale, K. breviceps • Dwarf sperm whale, K. sima • Kogia pusilla † • Kogia danomurai† • Genus Aprixokogia † • Pliokogia apenninica • Genus Praekogia† • Praekogia cedrosensis • Genus Scaphokogia† • Scaphokogia cochlearis • Genus Thalassocetus† • Thalassocetus antwerpiensis ==Biology==

Kogiid skulls are characterized by a very short rostrum, the smallest among extant cetaceans, as well as high levels of asymmetry, which is expected among odontocetes. Kogiid skulls have the most blunt mandible among extant cetaceans as well. Extant kogiidae also show relatively high encephalization quotient, the ratio between observed brain size and expected brain size. The pygmy sperm whale has an EQ of 1.78, while the dwarf sperm whale's EQ is 1.63. However, kogiid spermaceti is unique as the whales are able to control its temperature. Kogiidae are also homodonts, showing teeth all of the same size and shape. Kogiidae possess a unique system of organs to produce sound, including a bagpipe-like structure to produce sound and an amplifying horn. They are able to release over three gallons of this fecal "ink" to confuse or discourage predators. ==Ecology==

Range Kogiidae are believed to be cosmopolitan species, inhabiting all oceans except polar waters, remaining between the 50° latitude lines. Behavior and feeding Extant kogiids travel in small groups and rarely surface, potentially to avoid predators like orcas. Kogiidae are deep diving whales, believed to dive up to depths of 500 m. Pygmy sperm whales are able to eat larger prey than dwarf sperm whales, although their diet as a whole is relatively similar. ==Human threats==

Most observations of Kogia have come from individuals tangled in fishing line or stranded individuals. Both species of extant Kogia have also been observed stranded with plastics blocking their intestines. ==References==