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The image shows a full length view of an adult blue whale. Credit: NOAA Fisheries (TBjornstad).

The blue whale is usually studied in cetology.

Recent molecular genetics suggests that the blue whale may be closer in relation to the humpback whale (Megaptera) and the gray whale (Eschrichtius) than to the minke whales (Balaenoptera acutorostrata and Balaenoptera bonaerensis).[1]

Theoretical mammalogy[edit]

Def. the "study of mammals"[2] is called mammalogy.


A bottle-nosed dolphin (Tursiops truncatus) surfs the wake of a research boat on the Banana River near the Kennedy Space Center. Credit: NASA.

Def. the "branch of zoology concerned with whales, dolphins, and porpoises in the order Cetacea"[3] is called cetology.

Sperm whales[edit]

The image is of a sperm whale. Credit: Tim Cole, NMFS (NOAA).

The image at the right is an aerial view of an adult sperm whale Physeter macrocephalus. "Sperm whales have the largest brain of any animal (on average 17 pounds (7.8 kg) in mature males)".[4] These sentient whales have the largest brains that have ever existed on Earth.

"Absolute size is the most general of all brain properties [...], and ranges in mammals from brains of small bats and insectivores (weighing less than 0.1 g) to those of large cetaceans (up to 9000 g)."[5]

Omaru whales[edit]

These Omura whales lived in isolation for so long it was possible they did not want to be found. Credit: Asha de Vos.{{fairuse}}
Balaenoptera omurai is imaged off northwestern Madagascar. Credit: Salvatore Cerchio et al. / Royal Society Open Science.{{free media}}
The Omura’s whale is a real sweetheart. Credit: Asha de Vos.{{fairuse}}

"Omura whales have been reported at sizes of up to 124.5 feet."[6]

"This gentle giant [shown in the center frontal profile image], is shy and subtle."[6]

The holotype is an 11.03 m (36.2 ft) adult female, NSMT-M32505 (National Science Museum, Tokyo), which stranded at Tsunoshima (34°21'03"N 130°53'09"E) in the southern Sea of Japan on 11 September 1998. It includes a complete skeleton, both complete rows of baleen plates, and frozen pieces of muscle, blubber, and kidney collected by T. K. Yamada, M. Oishi, T. Kuramochi, E. Jibiki, and S. Fujioka. The type locality is the Sea of Japan, which may not be representative of the species’ typical range. The paratypes include the eight specimens (five females and three males), NRIFSF1-8 (National Research Institute of Far Seas Fisheries, Fisheries Research Agency, Shizuoka), collected by Japanese research vessels in the Indo-Pacific in the late 1970s. The longest baleen plate (NRIFSF6 includes 18 more baleen plates), an earplug, and a piece of the sixth thoracic vertebra with associated epiphysis were collected from each individual.[7][8]

Blue whales[edit]

This image shows an adult blue whale (Balaenoptera musculus) from the eastern Pacific Ocean. Credit: NMFS Northeast Fisheries Science Center (NOAA).
Blue whale off the coast of Sri Lanka in the Indian Ocean about 2018 is imaged before tissue sample taken by Asha de Vos. Credit: Crew member of Asha de Vos team, unnamed photographer.{{fairuse}}

The brain mass of one blue whale adult is 5,678 gms.[9] Although another adult was measured as about 6800 gms.[10]

"The blue whale, our largest known animal [such as the one imaged off the coast of Sri Lanka about 2018 on the left] is about 98.5 feet long."[6]

Baleen whales[edit]

Aetiocetus cotylalveus is an extinct whale that represents a transitional form between toothed and baleen whales. Credit: Smithsonian Institution/NMNH/A. Goswami/Phenome10K (USNM V 25210).{{fairuse}}
Janjucetus hunderi was discovered in Jan Juc, Victoria, Australia. Credit: Erich Fitzgerald/Monash University.{{fairuse}}

Aetiocetus is a genus of extinct basal mysticete, or baleen whale that lived 33.9 to 23.03 million years ago, in the late Oligocene in the North Pacific ocean, around Japan, Mexico, and Oregon, U.S. and currently contains known four species, A. cotylalveus, A. polydentatus, A. tomitai, and A. weltoni.[11]

A. cotylalveus is known from the Yaquina Formation of Oregon which is late Oligocene in age and at the cetacean's locality consists of a fine-grained grey sandstone with alternating layers of medium-grained light-grey sandstone and siltstone.[12] The Yaquina Formation represents a coastal marine depositional environment, and is considered late late Oligocene in age (Chattian) based on foraminifera and mollusc stages; approximately 24-25 million years in age. A. weltoni is also known from the Yaquina Formation and occurs along the same cliff face as A. cotylalveus, but occurs higher in the stratigraphic section, in situ near the contact of the conformably overlying Nye Formation, which is Miocene in age; thus, A. weltoni is very close to the Oligocene-Miocene boundary.[13]

A. tomitai was discovered in the Middle Hard Shale member of the Morawan Formation, Kawakami group in Japan, also late Oligocene in age and represents a basinal depositional environment, but not found in situ, instead in a loose concretion, and could potentially be stratigraphically higher than the Middle Hard Shale, not transported far from the location where it died.[13] A. polydentatus was also discovered in the Morawan Formation of Japan, but from the Upper Tuffaceous Siltstone Member, which also represents a basinal depositional environment, in situ in the uppermost part of the member.[13]

Aetiocetus shows some symplesiomorphic traits with more archaic whales that do not experience the same degree of telescoping as modern whales, so their nares, or nostrils, are still relatively anterior, contrary to the image of the modern baleen whales, Aetiocetus still possessed developed, enamelized adult teeth indicating that loss of functionality in relevant enamel genes, such as ameloblastin (AMBN), enamelin (ENAM), and amelogenin (AMEL), had not yet taken place in Aetiocetus.[14]

Skull of Janjucetus hunderi is shown in the image on the right. "The skull is just 50 centimetres long, meaning that the whale would be no larger than a bottle-nosed dolphin. The snout is foreshortened, quite unlike the surfboard-like elongated snouts of modern whales, which have adapted to increase their surface area for filter feeding. And the eye sockets are enormous relative to the whale's size."[15]

"A 25-million-year-old whale fossil from southeastern Australia has revealed a bizarre early type of 'baleen' whale. The creature was an ancient cousin of our modern blue whales and humpbacks, but it was hardly a gentle giant of the sea. Instead it was small and predatory, with enormous eyes and teeth."[15]

"Considering its shape and large eyes (providing good underwater vision), it looks as though this whale was a predator that ate large fish — possibly sharks and other whales."[16]

There "are specialized features in the fossil whale's anatomy - where the snout meets the brain case, and at the base of the skull near the ear region — that are unique to baleen whales. And Janjucetus can't echolocate, a defining feature of modern toothed whales, such as sperm whales and dolphins."[16]

There "is a blank period in the fossil record between ancient toothed whales that lived 34 million years ago, and a profusion of various lineages of whale and dolphin — including baleen whales — that came into being around 25 million years ago."[15]

Killer whales[edit]

This orca is Shamu. Credit: Terabyte.

The mean brain mass of Orcinus orca for six adults is 6,368 gms.[9]


This shows a head shot of an olive baboon (Papio anubis). Credit: Gary M. Stolz, United States Fish and Wildlife Service.

Def. the "branch of zoology relating to the study of primates"[17] is called primatology.


A study of horses is called equinology, or hippology.


Def. the "study of dogs"[18] is called cynology.


A malayan tiger is a mammal. Credit: B_cool from Singapore.

A study of cats is called felinology.


Def. the "study or science of rodents"[19] is called rodentology.


A bat collage is shown. Credit: MathKnight - Own work based on Uwe Schmidt C. Robiller / Naturlichter.de and Prof. emeritus Hans Schneider (Geyersberg) U.S. Fish and Wildlife Service Headquarters Anton 17.

Def. the study or science of bats is called chiropterology.

In the collage on the right are shown clockwise: Common Egyptian Fruit Bat Rousettus aegyptiacus, Mexican Free-Tail Bat Tadarida brasiliensis, Myotis myotis, Lesser Short-Nose Fruit Bat Cynopterus sphinx, Horseshoe Bat Rhinolophus ferrumequinum, and the Common Vampire Bat Desmodus rotundus.

See also[edit]


  1. Úlfur Árnason, Anette Gullberg, and Bengt Widegren (1993). "Cetacean mitochondrial DNA control region: sequences of all extant baleen whales and two sperm whale species". Molecular Biology and Evolution 10 (5): 960-70. http://mbe.oxfordjournals.org/content/10/5/960.abstract. Retrieved 2016-06-25. 
  2. mammalogy. San Francisco, California: Wikimedia Foundation, Inc. 16 December 2014. Retrieved 2015-02-23.
  3. SemperBlotto (9 December 2015). cetology. San Francisco, California: Wikimedia Foundation, Inc. Retrieved 2016-06-25.
  4. WF Perrin, B Wursig, and JGM Thewissen (13 November 2013). Sperm Whales (Physeter macrocephalus). NOAA. Retrieved 2014-09-23.CS1 maint: Multiple names: authors list (link)
  5. Gerhard Roth and Ursula Dicke (May 2005). "Evolution of the brain and intelligence". Trends in Cognitive Sciences 9 (5): 250-7. http://www.subjectpool.com/ed_teach/y3project/Roth2005_TICS_brain_size_and_intelligence.pdf. Retrieved 2014-09-23. 
  6. 6.0 6.1 6.2 Ariel Mark (17 July 2018). After Thirty Years of War, the Smoke Clears. Then, the Largest Animal Ever is Found Hiding. Discovery. Retrieved 19 July 2018.
  7. Balaenoptera omurai. Retrieved January 17, 2012.
  8. Wada, S.; Oishi, M.; Yamada, T.K. (2003). "A newly discovered species of living baleen whale". Nature 426 (6964): 278–281. doi:10.1038/nature02103. OCLC 110553472. PMID 14628049. 
  9. 9.0 9.1 Raymond J. Tarpley and Sam H. Ridgway (1994). "Corpus Callosum Size in Delphinid Cetaceans". Brain Behav Evol 44: 156-65. http://www.karger.com/Article/Abstract/113587. Retrieved 2014-09-23. 
  10. DB Tower (August 1954). "Structural and functional organization of mammalian cerebral cortex; the correlation of neurone density with brain size; cortical neurone density in the fin whale (Balaenoptera physalus L.) with a note on the cortical neurone density in the Indian elephant". J Comp Neurol 101 (1): 19-51. PMID 13211853. http://onlinelibrary.wiley.com/doi/10.1002/cne.901010103/full. Retrieved 2014-09-23. 
  11. "Aetiocetus". Fossilworks. Retrieved 27 October 2016.
  12. Douglas Emlong (1966). "A new archaic cetacean from the Oligocene of Northwest Oregon". Bulletin of the Museum of Natural History, University of Oregon 3: 1–51. 
  13. 13.0 13.1 13.2 Barnes, L. G.; Kimura, M.; Furusawa, H.; Sawamura, H. (1995). "Classification and distribution of Oligocene Aetiocetidae (Mammalia; Cetacea; Mysticeti) from western North America and Japan". The Island Arc 3 (4): 392–431. doi:10.1111/j.1440-1738.1994.tb00122.x. 
  14. Deméré, T. A.; Berta, A. (2008). "Skull anatomy of the Oligocene toothed mysticete Aetioceus weltoni (Mammalia; Cetacea): implications for mysticete evolution and functional anatomy". Zoological Journal of the Linnean Society 154 (2): 308–352. doi:10.1111/j.1096-3642.2008.00414.x. 
  15. 15.0 15.1 15.2 Richard Van Noorden (16 August 2006). Ancient whale 'truly weird' Blue whale's aged cousin: small, enormous eyes, ate sharks. Nature. Retrieved 10 March 2019.
  16. 16.0 16.1 Erich Fitzgerald (16 August 2006). Ancient whale 'truly weird' Blue whale's aged cousin: small, enormous eyes, ate sharks. Nature. Retrieved 10 March 2019.
  17. SemperBlotto (10 September 2007). primatology. San Francisco, California: Wikimedia Foundation, Inc. Retrieved 2016-06-25.
  18. (1 June 2007). cynology. San Francisco, California: Wikimedia Foundation, Inc. Retrieved 2016-06-25.
  19. Britespriteuk (22 June 2007). rodentology. San Francisco, California: Wikimedia Foundation, Inc. Retrieved 2016-06-25.

External links[edit]