What Is The Smallest Whale

Species of whale

Dwarf sperm whale[ane] Temporal range: Pliocene – Recent PreꞒ Ꞓ O S D C P T J K Pg N ↓ [ii]
Size compared to an boilerplate human
Conservation condition
Least Business organization (IUCN iii.1)[three]
CITES Appendix Ii (CITES)[iv]
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Artiodactyla
Infraorder:	Cetacea
Family:	Kogiidae
Genus:	Kogia
Species:	M. sima
Binomial name
Kogia sima (Owen, 1866)[iii]
Dwarf sperm whale range
Synonyms[5]
Kogia simus Owen, 1866 Physeter (Euphyseter) simus Owen, 1866 Callignathus simus Gill, 1871

The dwarf sperm whale ( Kogia sima ) is a sperm whale that inhabits temperate and tropical oceans worldwide, in item continental shelves and slopes. It was starting time described past biologist Richard Owen in 1866, based on illustrations by naturalist Sir Walter Elliot. The species was considered to be synonymous with the pygmy sperm whale (Kogia breviceps) from 1878 until 1998. The dwarf sperm whale is a small-scale whale, 2 to ii.seven yard (6 ft 7 in to 8 ft 10 in) and 136 to 272 kg (300 to 600 lb), that has a gray coloration, square caput, small jaw, and robust body. Its appearance is very similar to the pygmy sperm whale, distinguished mainly by the position of the dorsal fin on the trunk–nearer the centre in the dwarf sperm whale and nearer the tail in the other.

The dwarf sperm whale is a suction feeder that mainly eats squid, and does this in modest pods of typically one to 4 members. It is preyed upon past the killer whale (Orcinus orca) and big sharks such as the slap-up white shark (Carcharodon carcharius). When startled, the whale can eject a cloud of ruby-brown fluid. Most of what is known of the whale comes from beached individuals, equally sightings in the ocean are rare. Many of these stranded whales died from parasitic infestations or heart failure.

The dwarf sperm whale is hunted in small numbers around Asia. It is most threatened by ingesting, or getting entangled by, marine debris. No global population estimate has been made, and so its conservation condition by the International Union for Conservation of Nature (IUCN) is least concern.

Taxonomy [edit]

The first two dwarf sperm whale specimens, a male and a female person, were collected in 1853 by naturalist Sir Walter Elliot, who idea it a kind of porpoise due to the short snout. Still, when he sent drawings of these whales – including skeletal diagrams – to biologist Richard Owen to describe, Owen, in his 1866 paper, recognized it as a type of sperm whale in the family unit Physeteridae based on several similar characteristics, such equally having functional teeth in but the lower jaw, a lopsided blowhole leaning towards the left side, and a spermaceti organ. He named it Physeter (Euphysetes) simus, the same genus every bit the sperm whale (Physeter macrocephalus) and the pygmy sperm whale (now Kogia breviceps), with Euphysetes acting as a subgenus.^{[half dozen] [7]} The species name simus is Latin for "stump-nosed", a reference to its blunt snout. John Edward Gray, when he created the genus Kogia in 1846, gave no indication to the pregnant, but, since the word has a feminine ending, the masculine species proper noun simus had to exist inverse to sima to fit this when the combination Kogia simus was proposed by various 20th century authors.^{[7] [8]} In 1900, zoologist Frank Evers Beddard speculated that the word "might be a tribute to a Turk of the past surnamed Cogia Effendi, who observed whales in the Mediterranean".^[9]

In 1871, mammalogist Theodore Gill divide Physeteridae into two subfamilies: Physterinae with Physeter, and Kogiinae with Kogia and the now-defunct Euphysetes;^[10] this has now been elevated to family, Kogiidae.^[5] Gill besides proposed the dwarf sperm whale be moved to its ain genus, Calignathus. In 1878, naturalist James Hector synonymized the dwarf sperm whale with the pygmy sperm whales as Yard. breviceps. No distinction was made by most authors until mammalogist Dale Rice in his 1998 review of marine mammal taxonomy citing the works of Dr. Teizo Ogawa from 1936,^[11] researcher Munesato Yamada from 1954,^[12] zoologist Charles Handley from 1966,^[xiii] and mammalogist Graham James Berry Ross from 1979.^[fourteen]

Genetic testing in 2006 suggests that K. sima may actually represent two species, 1 in the Atlantic and 1 in the Indo-Pacific region. The Cape of Good Hope effectually South Africa may mark the barrier betwixt these 2 populations.^{[15] [16]}

Description [edit]

The dwarf sperm whale tin range in size from 2 to two.7 m (half dozen.half-dozen to viii.nine ft) in length and 136 to 272 kg (300 to 600 lb) in weight—less than the 4.25 m (fourteen ft) and 417 kg (920 lb) pygmy sperm whale. A newborn is more often than not effectually 1 k (three ft iii in) long and fourteen kg (31 lb). Males are thought to achieve physical maturity at age xv, and females at historic period xiii. Sexual maturity, which happens after an private has attained 2–2.2 m (half dozen ft 7 in – vii ft 3 in) in length, happens at 2 to 3 years for males and around 5 for females.^{[17] [7] [xviii]} Gestation takes place probably over around 9.5 months.^[seven]

The dwarf sperm whale has a dark-gray or blue-gray coloration with a lighter-gray underside, and a pale, crescent-shaped mark between the heart and the flipper, sometimes called a "fake gill", which is characteristic of the genus. Some individuals have been known to have a second crescent-shaped mark, creating a sort of stake ring encircling a darker spot. It has a high dorsal fin halfway downwards the length of the body, and two or more than throat grooves. The dorsal fin is taller and closer to the head than it is in the pygmy sperm whale, and the back is flatter.^{[16] [17] [19]}

Museum model of a dwarf sperm whale

Kogia is identified equally having a square head, a small jaw with the snout bulging outward, and a porpoise-like build with a robust body that rapidly decreases towards the tail. They take the shortest snouts of any modern twenty-four hour period whale. Characteristic of sperm whales, the left nostril is markedly larger than the right, and it has a spermaceti organ on its skull.^[17] The brain weighs around 0.v kg (1.1 lb).^[20] The eyes are adapted for depression-light environments. The dwarf sperm whale has xiv to 24 teeth, rarely 26, in the lower jaw that are sharp, slightly curved backwards, and–like other sperm whales–lack enamel. The teeth rarely exceed 30 mm (ane.two in) in length, smaller than those of the pygmy sperm whale. At most, vi teeth are in the upper jaws, though in modern sperm whales, upper teeth are defunct.^[17]

Unique to Kogia, there is a sac which hangs off from the pocket-sized intestines near the anus that is filled with a dense, red-brown fluid that looks like to chocolate syrup. When stressed, this fluid is released. The dwarf sperm whale has between 50 and 57 vertebrae, seven neck vertebrae, 12 to 14 thoracic vertebrae, and 29 or 35-to-37 lumbar vertebrae. The variation can either be due to loss of basic during preparation of a specimen, or individual variations. Information technology is non known to be sexually dimorphic.^{[17] [19]}

Population and distribution [edit]

The dwarf sperm whale ranges throughout tropical and temperate oceans of the world and inhabits the continental shelf and slope expanse.^[16] Information technology seems to prefer warmer waters than the pygmy sperm whale. The dwarf sperm whale is one of the nearly commonly beached deep-diving whales in the earth, though rarely seen at sea, and too, most data well-nigh the whale comes from examining beached individuals. Diving depth may vary from place to identify: a study in the Bahamas placed average depth at effectually 250 m (820 ft), whereas a written report in the deeper waters of Hawaii placed it at around 1,500 chiliad (iv,900 ft).^[21]

In the West Pacific, its recorded range spans from Japan to Tasmania and New Zealand, and in the East Pacific from British Columbia to key Chile. In the Indian Ocean, the whale is reported from Sultanate of oman, Sri Lanka, India, Thailand, Philippines, Indonesia effectually Timor, western Australia and South Africa. In the West Atlantic, it has been recorded from Virginia to southern Brazil, and in the E Atlantic from Italia in the Mediterranean Sea to South Africa.^[17]

No global population estimation has been made. Population counts accept been taken over sure areas, though given the difficulty to distinguish the dwarf sperm whale from the pygmy sperm whale, the overall approximate represents the full number of both species. In the North Atlantic, they are estimated at effectually 3,785 individuals;^[22] in the East Pacific, around 11,200 individuals.^[vii]

Ecology [edit]

Diet [edit]

The dwarf sperm whale is an open up ocean predator. The stomach contents of stranded dwarf sperm whales incorporate mainly squid and, to a lesser degree, deep sea fish (from the mesopelagic and bathypelagic zones) and crustaceans. However, crustaceans make up a sizable role of the diets of Hawaiian dwarf sperm whales, upwardly to 15%. The tummy contents of whales done up in different regions of the earth betoken a preference for erect-eyed squid and glass squid beyond its range, specially the elongate gem squid (Histioteuthis reversa) and Taonius.^[23]

The pharynx grooves and the developed musculature in the throat in Kogia are probably adaptations for increasing the volume of the mouth for suction feeding, possibly the all-time-developed amongst toothed whales. Too, the blunt snout, lack of teeth, and reduced jaw are characteristics seen in other suction feeding toothed whales. The whale uses its abrupt teeth to hold onto casualty while expelling h2o from the rima oris.^[24]

Dwarf sperm whale calves typically start eating solid food once they have reached a size of around 1.35 m (four ft 5 in) though are not fully weaned until they reach effectually 1.5 m (4 ft xi in). Toothed whale calves generally outset eating solid food at effectually 6 months, and mothers stop lactating after around eighteen to 20 months.^[seven]

Threats [edit]

Killer whales (Orcinus orca) and sharks are known to prey on the dwarf sperm whale.^{[21] [23]} Dwarf sperm whale remains take been institute in the stomachs of dandy white sharks (Carcharodon carcharias), and infestations of the cestode Phyllobothrium delphini in beached individuals indicates shark attacks since the cestode matures in sharks.^[seven]

The dwarf sperm whale too competes with other squid-eating whales, such as beaked whales. Information technology occupies the same ecological niche in the same regions every bit the pygmy sperm whale, though the latter can forage in deeper waters and has been known to feed on a wider array of species of larger size.^{[21] [23]}

Some beached individuals have had large parasitic infestations which probably lead to their death, item with nematodes in the tum and tapeworms in the blubber. In the southeastern Usa, stranded dwarf sperm whales were plant to have died from heart failure, and heart failure may have led to the stranding itself.^{[7] [25]}

Behavior [edit]

Dwarf sperm whales tend to float just nearly the surface.

Kogia is thought to be ho-hum-moving, rarely displaying rapid surfacing behavior, tending to bladder at the surface with but the nape and dorsal fin exposed. From the surface, they sink vertically, instead of lifting their tails out of the h2o to dive, which would create a splash.^[17]

The dwarf sperm whale congregates into small pods of one to four individuals, though on occasion up to x, likely due to express nutrient resources. Pocket-size group size and deep foraging grounds in the summer could as well be anti-predator behaviors. All the same, this is less likely as dolphins besiege in big pods with hundreds of members to foreclose predation. The whale probably follows seasonal squid migrations from offshore in the summer to nearshore in the wintertime. It is possible it prefers a gradient habitat as it allows the whale to herd squid against the wall, or information technology causes upwelling which the whale tin can ride on in gild to salve free energy while hunting.^{[16] [21] [26]} Younger animals may congregate in shallower areas and adults in deeper areas; the slope around South Africa may exist a nursery grounds.^[vii]

Kogia, unlike other whales, can eject a red-brown fluid when startled, likely to distract predators, similar to squid. This cloud tin cover 100 thou² (1,100 sq ft) in the water.^[17]

This species does not whistle, and instead produces narrowband high-frequency clicks. These clicks are more than similar to those produced by some dolphin and porpoise species–such every bit the hourglass dolphin (Sagmatias cruciger), Hector's dolphin (Cephalorhynchus hectori), the Chilean dolphin (Cephalorhynchus eutropia), Commerson'south dolphin (Cephalorhynchus commersonii), the harbour porpoise (Phocoena phocoena), and Dall'south porpoise (Phocoenoides dalli)–than to those of other deep-diving whales, such as beaked whales and the sperm whale. The peak frequencies of Kogia are more often than not less than 130 kHz.^[27]

Relationship with humans [edit]

There is some hunting of the dwarf sperm whale in Indonesia, Nihon, Sri Lanka, and the Bottom Antilles as food or allurement, though in that location are no major operations. A bigger threat is likely ingestion of marine debris and entanglement in line-fishing gear, though it has not been determined how serious a threat these pose.^{[28] [7]} The International Wedlock for Conservation of Nature (IUCN) currently lists the dwarf sperm whale's conservation status as data deficient, though it could possibly exist of to the lowest degree concern.^[iii]

The dwarf sperm whale is covered past the Convention on International Merchandise in Endangered Species of Wild animals and Flora (CITES),^[17] the Agreement on the Conservation of Cetaceans in the Black Ocean, Mediterranean Sea and Contiguous Atlantic Expanse.^[29] The species is further included in the Memorandum of Understanding Concerning the Conservation of the Manatee and Small Cetaceans of Western Africa and Macaronesia (Western African Aquatic Mammals MoU),^[30] and the Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region (Pacific Cetaceans MoU).^[31]

Come across also [edit]

• Kogia pusilla
• Listing of cetaceans

References [edit]

1. ^ Mead, J. Thou.; Brownell, R. L. Jr. (2005). "Lodge Cetacea". In Wilson, D. East.; Reeder, D. Yard. (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Printing. p. 737. ISBN978-0-8018-8221-0. OCLC 62265494.
2. ^ Fossilworks works 2013. "fossilworks". fossilworks.
3. ^ ^{a b c} Kiszka, J.; Braulik, Thousand. (2020). "Kogia sima". IUCN Red Listing of Threatened Species. 2020: e.T11048A50359330. doi:ten.2305/IUCN.Great britain.2020-ii.RLTS.T11048A50359330.en . Retrieved xix November 2021.
4. ^ "Appendices | CITES". cites.org . Retrieved 2022-01-14 .
5. ^ ^{a b} Perrin WF, ed. (2009). "Kogiidae". World Cetacea Database. World Annals of Marine Species. Retrieved 6 August 2018.
6. ^ Owen, R. (1866). "On some Indian Cetacea nerveless by Walter Elliot, Esq". Transactions of the Zoological Society of London. 6 (one): 17–47. doi:10.1111/j.1096-3642.1866.tb00570.x.
7. ^ ^{a b c d e f g h i j} Plön, Stephanie (January 2004). The Status and Natural History of Pygmy (Kogia breviceps) and Dwarf (K. sima) Sperm Whales off Southern Africa (PDF) (Thesis). Rhodes University.
8. ^ Rice, D. Westward. (1998). Marine Mammals of the World: Systematics and Distribution (PDF). Society for Marine Mammalogy. pp. 84–85. ISBN978-1-891276-03-iii.
9. ^ Frank Evers Beddard (1900). A Book of Whales. London, J. Murray; New York, G.P. Putnam's Sons. p. 186.
10. ^ Gill, T. (1871). "The Sperm Whales, Giant and Pygmy". American Naturalist. four (12): 725–743. doi:x.1086/270684. S2CID 84450779.
11. ^ Ogawa, T. (1936). "Studien über die Zahnwale in Japan" [Studies on the Toothed Whales in Japan]. Mitteil: Botany & Zoology (in Japanese). 4: 2017–2023.
12. ^ Yamada, Thou. (1954). "Some Remarks on the Pygmy Sperm Whale, Kogia" (PDF). Scientific Reports of the Whales Inquiry Institute. nine: 37–58.
13. ^ Handley, C. O. (1966). "A Synopsis of the Genus Kogia (pygmy sperm whale)". In Norris, K. S. (ed.). Whales, Dolphins, and Porpoises. Academy of California Press. pp. 62–69.
14. ^ Ross, G. J. B. (1979). Records of Pygmy and Dwarf Sperm Whales, Genus Kogia, from Southern Africa, with Biological Notes and Some Comparisons. Annals of the Cape Provincial Museums Natural History. Cape Provincial Museums. pp. 1–60.
15. ^ Chivers, Due south. J.; Leduc, R. G.; Robertson, G. M.; Barros, N. B.; Dizon, A. E. (2006). "Genetic Variation of Kogia spp. with Preliminary Evidence for Two Species of Kogia sima". Marine Mammal Science. 21 (4): 619–634. CiteSeerX10.one.ane.222.2209. doi:10.1111/j.1748-7692.2005.tb01255.x.
16. ^ ^{a b c d} Rudolph, P; Smeenk, C. (2009). "Indo-West Pacific Marine Mammals". In Perrin, W. F.; Würsig, B.; Thewissen, J. G. M. (eds.). Encyclopedia of Marine Mammals. Academic Press. p. 611. ISBN978-0-08-091993-5.
17. ^ ^{a b c d e f one thousand h i} Willis, P. M.; Baird, R. Westward. (1998). "Condition of the dwarf sperm whale, Kogia simus, with special reference to Canada" (PDF). Oceanographic Literature Review. 112 (ane): 114–125.
18. ^ Nagorsen, David (1985). "Kogia simus" (PDF). Mammalian Species (239): one–6. doi:10.2307/3503937. JSTOR 3503937.
19. ^ ^{a b} Bonato, Marco; Webber, Marc A.; Attoumane, Artadji; Giacoma, Cristina (2016). "First records of dwarf sperm whale (Kogia sima) from the Matrimony of the Comoros". Marine Biodiversity Records. 9 (1). doi:x.1186/s41200-016-0064-z. S2CID 5014340.
20. ^ Marino, L.; Sudheimer, K.; Pabst, D. A.; McLellan, W. A.; Johnson, J. I. (2003). "Magnetic resonance images of the brain of a dwarf sperm whale (Kogia simus)". Journal of Beefcake. 203 (i): 57–76. doi:ten.1046/j.1469-7580.2003.00199.x. PMC1571141. PMID 12892406.
21. ^ ^{a b c d} Dunphy-Daly, M. M.; Heithaus, Thousand. R. (2007). "Temporal Variation in Dwarf Sperm Whale (Kogia sima) Habitat Utilise and Group Size off Not bad Abaco Island, the Commonwealth of the bahamas". doi:10.25148/etd.fi15101248.
22. ^ Hayes SA, Josephson E, Maze-Foley K, Rosel PE, eds. (June 2016). "Dwarf Sperm Whale (Kogia sima): Western N Atlantic Stock" (PDF). US Atlantic and Gulf of Mexico Marine Mammal Stock Assessments - 2016 (Technical report). National Marine Fisheries Service. doi:10.7289/V5/TM-NEFSC-241. NMFS-NE-241.
23. ^ ^{a b c} Staudinger, M. D.; McAlarney, R. J.; McLellan, W. A.; Pabst, D. A. (2013). "Foraging environmental and niche overlap in pygmy (Kogia breviceps) and dwarf (Kogia sima) sperm whales from waters of the U.S. mid‐Atlantic coast". Marine Mammal Science. 30 (2): 626–655. doi:10.1111/mms.12064.
24. ^ Bloodworth, B.; Marshall, C. D. (2005). "Feeding Kinematics of Kogia and Tursiops (Odontoceti: Cetacea): Label of Suction and Ram Feeding". Journal of Experimental Biology. 208 (Pt 19): 3721–3730. doi:x.1242/jeb.01807. PMID 16169949. S2CID 6949085.
25. ^ Bossart, G. D.; Odell, D. K.; Altman, N. H. (1985). "Cardiomyopathy in Stranded Pygmy and Dwarf Sperm Whales". Journal of the American Veterinary Medical Clan. 187 (11): 1137–1140. PMID 4077624.
26. ^ Bermúdez Villapol, A Luis; Sayegh, Alejandro; León, Tatiana (2008). "Notes on the confirmation of the Dwarf sperm whale Kogia sima Owen, 1866 (Cetacea: Kogiidae) on Venezuelan coasts". Revista Científica UDO Agrícola. 8 (1): 154–162 – via Bioline.
27. ^ Merkens, 1000.; Mann, D.; Janik, 5. Thou.; Clarige, D.; Colina, M.; Oleson, E. (2018). "Clicks of Dwarf Sperm Whales (Kogia sima)". Marine Mammal Scientific discipline. 34 (iv): 963–978. doi:x.1111/mms.12488. hdl:10023/17127.
28. ^ Reeves, R. R.; Smith, B. D.; di Sciara, Grand. N. (2003). 2002–2010 Conservation Activity Programme for the World'due south Cetaceans (PDF). IUCN/SSC Cetacean Specialist Group: Dolphins, Whales and Porpoises. ISBN978-2-8317-0656-half dozen.
29. ^ "Agreement on the Conservation of Cetaceans in the Blackness Sea, Mediterranean Sea and Contiguous Atlantic Area" (PDF). 1996.
30. ^ "Kogia sima". Convention on the Conservation of Migratory Species of Wild animals.
31. ^ "Diverseness Database". Pacific Cetaceans Memorandum of Understanding. Archived from the original on 2012-03-31.

Further reading [edit]

Wikimedia Commons has media related to Kogia sima.

• Whales Dolphins and Porpoises, Mark Carwardine, Dorling Kindersley Handbooks, ISBN 978-0-7513-2781-6
• National Audubon Gild Guide to Marine Mammals of the Earth, Reeves, Stewart, Clapham and Powell, ISBN 978-0-375-41141-0

External links [edit]

• Whale & Dolphin Conservation Gild (WDCS)

What Is The Smallest Whale,

Source: https://en.wikipedia.org/wiki/Dwarf_sperm_whale

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