Kogiidae

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Kogiidae
Temporal range: Miocene – Recent
↓
[1]
Dwarf sperm whale, Kogia sima
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Infraorder: Cetacea
Superfamily: Physeteroidea
Family: Kogiidae
Gill, 1871
Genera

See text

Kogiidae is a family comprising at least two extant species of Cetacea, the pygmy (Kogia breviceps) and dwarf (K. sima) sperm whales. As their common names suggest, they somewhat resemble sperm whales, with squared heads and small lower jaws, but are much smaller in size, with much shorter skulls and more notable dorsal fins than sperm whales.[2] Kogiids are also characterized by a "false gill slit" behind their eyes.[3]

A number of genera are extinct.[4]

Taxonomy

There is some amount of uncertainty over if Kogiidae belongs in the

Platanista and kogiids.[7] Fossil evidence is limited for this family, which potentially limits an understanding of their relationship to other extant cetaceans.[8]

Researchers have proposed that K. sima may represent at least two genetically unique species, and further genetic research is needed to determine the real number of extant species of Kogiidae.

Praekogia cedrosensis (bottom), both from the Late Miocene
.

ORDER

ARTIODACTYLA

Biology

Kogiid skulls are characterized by a very short

homodonts, showing teeth all of the same size and shape.[15]

Kogiidae possess a unique system of organs to produce sound, including a bagpipe-like structure to produce sound and an amplifying horn.[14]

Kogiidae have a modified colon which works as an "ink sac", storing liquid red feces.[16] They are able to release over three gallons of this fecal "ink" to confuse or discourage predators.[17]

Ecology

Range

Kogiidae are believed to be

cosmopolitan species, inhabiting all oceans except polar waters, remaining between the 50° latitude lines.[16]

Two fossilized species of Kogia sp. were shown to exhibit sympatry, similar to the two modern members of Kogia, which researchers suggested shows that this behavior has been part of Kogiidae for at least 3 million years.[18]

Behavior and feeding

Extant kogiids travel in small groups and rarely surface, potentially to avoid predators like orcas.[19]

Kogiidae are deep diving whales, believed to dive up to depths of 500 m.[8] Kogiids feed using a technique known as suction feeding, and their diet primarily consists of squid.[20][21] Pygmy sperm whales are able to eat larger prey than dwarf sperm whales, although their diet as a whole is relatively similar.[21] They have also been observed using echolocation to find their prey, and their hearing places them in the "Very High Frequency" group of cetaceans that can hear well above 100 kHz.[22][23]

Human threats

Most observations of Kogia have come from individuals tangled in fishing line or stranded individuals.[8] There is a commercial fishery for K. breviceps in parts of southeast Asia and the Lesser Antilles.[24] Both species of extant kogiidae have also been observed stranded with plastics blocking their intestines.[17][24]

References

  1. ^ "Fossilworks: Kogiidae".
  2. OCLC 30643250.{{cite book}}: CS1 maint: multiple names: authors list (link
    )
  3. OCLC 237402526
    .
  4. ^
    hdl:2246/3135. {{cite journal}}: Cite journal requires |journal= (help
    )
  5. ^
    PMID 16325433
    .
  6. S2CID 84103043
    .
  7. PMID 15336663
    .
  8. ^
    ISBN 9780080919935
    .
  9. ISSN 1748-7692
    .
  10. ^
    PMID 25923213
    .
  11. hdl:11568/1000367
    .
  12. doi:10.1111/jzo.12425
    .
  13. ISSN 1413-9596
    .
  14. ^
    S2CID 84103043
    .
  15. ^ "Cetacean Palaeobiology". palaeo.gly.bris.ac.uk. Retrieved 2017-12-05.
  16. ^
    ISSN 0076-3519
    .
  17. ^ a b Fisheries, NOAA (2017-05-05). "Dwarf Sperm Whale (Kogia sima) :: NOAA Fisheries". www.nmfs.noaa.gov. Retrieved 2017-11-22.
  18. S2CID 130506478
    .
  19. PMID 17584238
    .
  20. PMID 16169949
    .
  21. ^
    ISSN 1748-7692
    .
  22. ISSN 0001-4966
    .
  23. S2CID 91521545
    .
  24. ^ a b Fisheries, NOAA (2017-05-05). "Pygmy Sperm Whale (Kogia breviceps) :: NOAA Fisheries". www.nmfs.noaa.gov. Retrieved 2017-11-17.
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