Cetacea is an infraorder that comprises the 89 species of whales, dolphins, and porpoises. It is divided into toothed whales (Odontoceti) and baleen whales (Mysticeti), which diverged from each other some time in the Eocene 26 to 17 million years ago (mya). Cetaceans are descended from land-dwelling hoofed mammals, and the now extinct archaeocetes represent the several transitional phases from terrestrial to completely aquatic.[1] Historically, cetaceans were thought to have descended from the wolf-like mesonychids, but cladistic analyses confirm their placement with even-toed ungulates in the order Cetartiodactyla.[2][3][4][5][6]

Whale populations were drastically reduced in the 20th century from intensive whaling, and the activity was globally banned in 1982.[7] Smaller cetaceans are at risk of accidentally getting caught by fishing vessels using, namely, seine fishing, drift netting, or gill netting operations.[8]

ConventionsEdit

IUCN Red List categories
Conservation status
 EX Extinct (0 species)
 EW Extinct in the wild (0 species)
 CR Critically endangered (3 species)
 EN Endangered (10 species)
 VU Vulnerable (7 species)
 NT Near threatened (6 species)
 LC Least concern (37 species)
Other categories
 DD Data deficient (27 species)
 NE Not evaluated (3 species)

The following is a list of existing (extant) species of the infraorder cetacea, organized taxonomically into parvorders, superfamilies when applicable, families, subfamilies when applicable, genus, and then species. In tabular form, seven descriptors are given for each species: the common name; the scientific name; the IUCN Red List status; a global population estimate; a global map with its range; its weight with an image of its shape, and its size relative to a human; and a photograph.

Conservation status codes listed follow the IUCN Red List of Threatened Species (v. 2014.3; data current at 20 January 2015).[9]

Where available, the global population estimate has been listed. When not cited or footnoted differently, these are from the IUCN Red List of Threatened Species (v. 2014.3; data current at 20 January 2015).[9]

Mysticeti: baleen whalesEdit

The baleen whales, also called whalebone whales or great whales, form the Mysticeti. Baleen whales are characterized by having baleen plates for filter feeding and two blowholes. During the embryonic phase, Mysticetes do have teeth but they are reabsorbed before birth.[10]

Family Balaenidae: right whalesEdit

The family Balaenidae contains two genera and four species. All the Balaenidae whales have no ventral grooves; a distinctive head shape with a strongly arched, narrow rostrum, bowed lower jaw; lower lips that enfold the sides and front of the rostrum; long, narrow, elastic baleen plates (up to nine times longer than wide) with fine baleen fringes; and fused cervical vertebrae rendering the head immobile.[11]

Genus Balaena Linnaeus, 1758 – one species
Common name Scientific name IUCN Red List status Global population estimate Range Size Picture
Bowhead whale Balaena mysticetus
Linnaeus, 1758
LC IUCN 12,682–39,950    
60 tonnes
 
Genus Eubalaena Gray, 1864 – 3 species
Common name Scientific name IUCN Red List status Global population estimate Range Size Picture
North Atlantic right whale Eubalaena glacialis
Müller, 1776
EN IUCN 300-350    
40–80 tonnes
 
North Pacific right whale Eubalaena japonica
Lacépède, 1818
EN IUCN 404-2,108[12]    
60–80 tonnes
 
Southern right whale Eubalaena australis
Desmoulins, 1822
LC IUCN 7,500    
40–80 tonnes
 

Family Balaenopteridae: rorqualsEdit

Rorquals are the largest group of baleen whales, with nine species in two genera. They include the largest animal that has ever lived, the blue whale, which can reach 190 tonnes, the fin whale can easily reach 50 tonnes, and even the smallest of the group, the northern minke whale, reaches 9 tonnes. They take their name from a Norwegian word meaning "furrow whale": all members of the family have a series of longitudinal folds of skin running from below the mouth back to the navel (except the sei whale, which has shorter grooves). These are understood to allow the mouth to expand immensely when feeding.[13] All rorquals have ventral grooves, and are the only cetaceans to have them. Additionally, they all have dorsal fins, broad, gently curving rostra and short baleen plates.[11]

Subfamily Balaenopteridae – one genus, eight species
Genus Balaenoptera – eight species
Common name Scientific name Status Population Distribution Size Picture
Blue whale Balaenoptera musculus
Linnaeus, 1758
EN IUCN 10,000–25,000    
50-150 tonnes
 
Bryde's whale Balaenoptera brydei
Olsen, 1913
LC IUCN 90,000–100,000    
14–30 tonnes
 
Common minke whale Balaenoptera acutorostrata
Lacépède, 1804
LC IUCN 200,000    
6-11 tonnes
 
Eden's whale[a] Balaenoptera edeni
Anderson, 1879
LC IUCN Unknown   Unknown  
Fin whale Balaenoptera physalus
Linnaeus, 1758
VU IUCN 100,000    
30–80 tonnes
 
Omura's whale Balaenoptera omurai
Wada et al., 2003
DD IUCN Unknown Unknown Unknown  
Sei whale Balaenoptera borealis
Lesson, 1828
EN IUCN 57,000    
20–25 tonnes
 
Antarctic minke whale Balaenoptera bonaerensis
Burmeister, 1867
NT IUCN 515,000    
6-10 tonnes
 
Subfamily Megapterinae – 1 genus, 1 species
Genus Megaptera Gray, 1846 – 1 species
Common name Scientific name Status Population Distribution Size Picture
Humpback whale Megaptera novaeangliae
Borowski, 1781
LC IUCN 80,000    
25–30 tonnes
 

Family Cetotheriidae: pygmy right whaleEdit

The pygmy right whale shares several characteristics with the right whales, although having dorsal fins separates them from right whales, and they have a very distinctive jaw configuration. Pygmy right whales' heads are no more than one-fourth the size of their bodies, whereas the right whales' heads are about one-third the size of their bodies.[11] The pygmy right whale is the only extant member of its family, otherwise better characterized by the extinct genus Cetotherium.

Genus Caperea Gray, 1864 – 1 species
Common name Scientific name Status Population Distribution Size Picture
Pygmy right whale Caperea marginata
Gray, 1846
LC IUCN Unknown    
3-3.5 tonnes
 

Family Eschrichtiidae: gray whaleEdit

The gray whale has been placed in a family of its own, as it is sufficiently different from the right whales and the rorquals. The gray whale is the only benthic feeding baleen whale, filtering small organisms from the mud of shallow seas. They also have a gestation period of over a year, which is unusual for baleen whales.[11]

Genus Eschrichtius – 1 species
Common name Scientific name Status Population Distribution Size Picture
Gray whale Eschrichtius robustus
Lilljeborg, 1861
LC IUCN 26,000    
15–40 tonnes
 

Odontoceti: toothed whalesEdit

The toothed whales (systematic name Odontoceti) form a parvorder of the cetaceans. As the name suggests, the parvorder is characterized by having teeth (rather than baleen). Toothed whales are active hunters, feeding on fish, squid, and in some cases other marine mammals.

Family Delphinidae: oceanic dolphinsEdit

Oceanic dolphins are the members of the cetacean family Delphinidae. These aquatic mammals are related to whales and porpoises. As the name implies, these dolphins tend to be found in the open seas, unlike the river dolphins, although a few species such as the Irrawaddy dolphin are coastal or riverine. Six of the larger species in the Delphinidae, the killer whale (orca) and its relatives, are commonly called whales, rather than dolphins. They are also sometimes collectively known as "blackfish".

The Delphinidae are characterized by having distinct beaks (unlike the Phocoenidae), two or more fused cervical vertebrae and 20 or more pairs of teeth in their upper jaws. None is more than 4 m long.[11]

Genus Cephalorhynchus Gray, 1846 – four species
Common name Scientific name Status Population Distribution Size Picture
Chilean dolphin Cephalorhynchus eutropia
Gray, 1846
NT IUCN Unknown    
60 kg
 
Commerson's dolphin Cephalorhynchus commersonii
Lacépède, 1804
LC IUCN 3,400    
35–60 kilograms
 
Heaviside's dolphin Cephalorhynchus heavisidii
Gray, 1828
NT IUCN Unknown    
40–75 kg
 
Hector's dolphin Cephalorhynchus hectori
Van Beneden, 1881
EN IUCN (subspecies Māui dolphin CR IUCN) 12,000–18,500 (subspecies Māui dolphin 57–75 in 2016)    
35–60 kg
 
Genus Delphinus – three species
Common name Scientific name Status Population Distribution Size Picture
Arabian common dolphin[b] Delphinus tropicalis
van Bree, 1971
NE Unknown  
65–105 kg
 
Long-beaked common dolphin[c] Delphinus capensis
Gray, 1828
DD IUCN Unknown [d]    
80–150 kg
 
Short-beaked common dolphin Delphinus delphis
Linnaeus, 1758
LC IUCN Unknown    
70–110 kg
 
Genus Feresa – one species
Common name Scientific name Status Population Distribution Size Picture
Pygmy killer whale Feresa attenuata
Gray, 1875
LC IUCN Unknown [e]    
160–350 kg
 
Genus Globicephala – two species
Common name Scientific name Status Population Distribution Size Picture
Long-finned pilot whale Globicephala melas
Traill, 1809
LC IUCN Unknown [f]    
3-3.5 tonnes
 
Short-finned pilot whale Globicephala macrorhynchus
Gray, 1846
LC IUCN Unknown [g]    
1–3 tonnes
 
Genus Grampus – one species
Common name Scientific name Status Population Distribution Size Picture
Risso's dolphin Grampus griseus
G. Cuvier, 1812
LC IUCN Unknown [h]    
300 kg
 
Genus Lagenodelphis – one species
Common name Scientific name Status Population Distribution Size Picture
Fraser's dolphin Lagenodelphis hosei
Fraser, 1956
LC IUCN Unknown    
209 kg
 
Genus Lagenorhynchus Gray, 1846 – six species
Common name Scientific name Status Population Distribution Size Picture
Atlantic white-sided dolphin Lagenorhynchus acutus
Gray, 1828
LC IUCN 200,000 – 300,000    
235 kg
 
Dusky dolphin Lagenorhynchus obscurus
Gray, 1828
LC IUCN Unknown    
100 kg
 
Hourglass dolphin Lagenorhynchus cruciger
Quoy & Gaimard, 1824
LC IUCN 140,000    
90–120 kg
 
Pacific white-sided dolphin Lagenorhynchus obliquidens
Gill, 1865
LC IUCN 1,000,000    
85–150 kg
 
Peale's dolphin Lagenorhynchus australis
Peale, 1848
LC IUCN Unknown [i]    
115 kg
 
White-beaked dolphin Lagenorhynchus albirostris
Gray, 1846
LC IUCN 100,000 [j]    
180 kg
 
Genus Lissodelphis – two species
Common name Scientific name Status Population Distribution Size Picture
Northern right whale dolphin Lissodelphis borealis
Peale, 1848
LC IUCN 400,000 [k]    
115 kg
 
Southern right whale dolphin Lissodelphis peronii
Lacépède, 1804
LC IUCN Unknown [l]    
60–100 kg
 
Genus Orcaella Gray, 1866 – two species
Common name Scientific name Status Population Distribution Size Picture
Australian snubfin dolphin Orcaella heinsohni
Beasley, Robertson & Arnold, 2005
VU IUCN 9,000 - 10,000    
130–145 kg
 
Irrawaddy dolphin Orcaella brevirostris
Gray, 1866
EN IUCN Unknown    
130 kg
 
Genus Orcinus – one species
Common name Scientific name Status Population Distribution Size Picture
Killer whale Orcinus orca
Linnaeus, 1758
DD IUCN 100,000 [m]    
4.5 tonnes
 
Genus Peponocephala – one species
Common name Scientific name Status Population Distribution Size Picture
Melon-headed whale Peponocephala electra
Gray, 1846
LC IUCN Unknown [n]    
225 kg
 
Genus Pseudorca – one species
Common name Scientific name Status Population Distribution Size Picture
False killer whale Pseudorca crassidens
Owen, 1846
NT IUCN Unknown [o]    
1.5-2 tonnes
 
Genus Sousa – four species
Common name Scientific name Status Population Distribution Size Picture
Atlantic humpback dolphin Sousa teuszi
Kükenthal, 1892
CR IUCN 1,500    
100–150 kg
(cetacean needed)
Australian humpback dolphin Sousa sahulensis
Jefferson & Rosenbaum, 2014
VU IUCN 10,000  
Indian Ocean humpback dolphin Sousa plumbea
Cuvier, 1829
EN IUCN Unknown      
Indo-Pacific humpback dolphin Sousa chinensis
Osbeck, 1765
VU IUCN Unknown    
250–280 kg
 
Genus Sotalia – two species
Common name Scientific name Status Population Distribution Size Picture
Guiana dolphin Sotalia guianensis
Bénéden, 1864
NT IUCN Unknown  
Solid color
 
35–45 kg
 
Tucuxi Sotalia fluviatilis
Gervais & Deville, 1853
DD IUCN Unknown  
Hashed color
 
35–45 kg
 
Genus Stenella Gray, 1866 – five species
Common name Scientific name Status Population Distribution Size Picture
Atlantic spotted dolphin Stenella frontalis
Cuvier, 1829
LC IUCN 100,000    
100 kg
 
Clymene dolphin Stenella clymene
Gray, 1846
LC IUCN Unknown    
75–80 kg
 
Pantropical spotted dolphin Stenella attenuata
Gray, 1846
LC IUCN 3,000,000    
100 kg
 
Spinner dolphin Stenella longirostris
Gray, 1828
LC IUCN Unknown    
90 kg
 
Striped dolphin Stenella coeruleoalba
Meyen, 1833
LC IUCN 2,000,000    
100 kg
 
Genus Steno – one species
Common name Scientific name Status Population Distribution Size Picture
Rough-toothed dolphin Steno bredanensis
Lesson, 1828
LC IUCN 150,000    
100–135 kg
 
Genus Tursiops – three species
Common name Scientific name Status Population Distribution Size Picture
Burrunan dolphin[p] Tursiops australis
Charlton-Robb, 2011
NE Unknown  
Common bottlenose dolphin Tursiops truncatus
Montagu, 1821
LC IUCN 600,000[15]    
150–650 kg
 
Indo-Pacific bottlenose dolphin Tursiops aduncus
Ehrenberg, 1833
DD IUCN Unknown  
230 kg
 

Family Monodontidae: narwhal and belugaEdit

The cetacean family Monodontidae comprises two unusual whale species, the narwhal, in which the male has a long tusk, and the white beluga.

The Monodontidae lack dorsal fins, which have been replaced by tough, fibrous ridges just behind the midpoints of their bodies and are probably an adaptation to swimming under ice, as both do in their Arctic habitat. The flippers are small, rounded and tend to curl up at the ends in adulthood. All, or almost all, the cervical vertebrae are unfused, allowing their heads to be turned independently of their bodies. None has any throat grooves.[11]

Genus Delphinapterus – one species
Common name Scientific name Status Population Distribution Size Picture
Beluga Delphinapterus leucas
Pallas, 1776
LC IUCN 100,000 [q]    
1.5 tonnes
 
Genus Monodon – one species
Common name Scientific name Status Population Distribution Size Picture
Narwhal Monodon monoceros
Linnaeus, 1758
LC IUCN 25,000 [r]    
900-1,500 kilograms
 

Family Kogiidae: dwarf and pygmy sperm whalesEdit

The dwarf and pygmy sperm whales resemble sperm whales, but are far smaller. They are dark gray, dorsally, while ventrally they are lighter. They have blunt, squarish heads with narrow, underslung jaws; the flippers are set far forward, close to the head and their dorsal fins are set far back down the body.

Genus Kogia – two species
Common name Scientific name Status Population Distribution Size Picture
Dwarf sperm whale Kogia sima
Owen, 1866
DD IUCN Unknown [s]    
250 kg
 
Pygmy sperm whale Kogia breviceps
Blainville, 1838
DD IUCN Unknown [t]    
400 kg
 

Family Phocoenidae: porpoisesEdit

Porpoises are small cetaceans of the family Phocoenidae. They are distinct from dolphins, although the word "porpoise" has been used to refer to any small dolphin, especially by sailors and fishermen. The most obvious visible difference between the two groups is porpoises have spatulate (flattened) teeth distinct from the conical teeth of dolphins. In addition, porpoises are relatively r-selected compared with dolphins: that is, they rear more young more quickly than dolphins. All seven species have small flippers, notched tail flukes, and no beaks. All carry at least 11 pairs of small teeth in their upper and lower jaws.

Porpoises, divided into seven species, live in all oceans, mostly near the shore. Probably best known is the harbour porpoise, which can be found across the Northern Hemisphere.

Genus Neophocaena – two species
Common name Scientific name Status Population Distribution Size Picture
Indo-pacific finless porpoise Neophocaena phocaenoides
Cuvier, 1829
VU IUCN[u] Unknown [v]    
30–45 kg
 
Narrow-ridged finless porpoise Neophocaena asiaeorientalis
Cuvier, 1829
EN IUCN[w] 1,000    
30–45 kg
 
Genus Phocoena – four species
Common name Scientific name Status Population Distribution Size Picture
Burmeister's porpoise Phocoena spinipinnis
Burmeister, 1865
NT IUCN Unknown [x]    
50–75 kg
(cetacean needed)
Harbour porpoise Phocoena phocoena
Linnaeus, 1758
LC IUCN 700,000 [16]    
75 kg
 
Spectacled porpoise Phocoena dioptrica
Lahille, 1912
LC IUCN Unknown [y]    
60–84 kg
(cetacean needed)
Vaquita Phocoena sinus
Norris & McFarland, 1958
CR IUCN 12 [17]    
50 kg
 
Genus Phocoenoides – 1 species
Common name Scientific name Status Population Distribution Size Picture
Dall's porpoise Phocoenoides dalli
True, 1885
LC IUCN 1,100,000 [z]    
130–200 kg
 

Family Physeteridae: sperm whaleEdit

The sperm whale characteristically has a large, squarish head one-third the length of its body; the blowhole is slightly to the left hand side; the skin is usually wrinkled; and it has no teeth on the upper jaw.

Genus Physeter – one species
Common name Scientific name Status Population Distribution Size Picture
Sperm whale Physeter macrocephalus
Linnaeus, 1758
VU IUCN 200,000–2,000,000 [aa]    
25–50 tonnes
 

Family Ziphiidae: beaked whalesEdit

A beaked whale is any of at least 22 species of small whale in the family Ziphiidae. They are one of the least-known families of large mammals: several species have only been described in the last two decades, and it is entirely possible that more remain as yet undiscovered. Six genera have been identified.

They possess a unique feeding mechanism known as suction feeding. Instead of catching their prey with teeth, it is sucked into their oral cavity. Their tongue can move very freely, and when suddenly retracted at the same time as the gular floor is distended, the pressure immediately drops within their mouth and the prey is sucked in with the water. The family members are characterized by having a lower jaw that extends at least to the tip of the upper jaw, a shallow or non-existent notch between the tail flukes, a dorsal fin set well back on the body, three of four fused cervical vertebrae, extensive skull asymmetry and two conspicuous throat grooves forming a 'V' pattern.[11]

Genus Berardius – two species
Common name Scientific name Status Population Distribution Size Picture
Arnoux's beaked whale Berardius arnuxii
Duvernoy, 1851
DD IUCN Unknown [ab]    
8 tonnes
 
Baird's beaked whale Berardius bairdii
Stejneger, 1883
DD IUCN Unknown [ac]    
12 tonnes
(cetacean needed)
Berardius minimus Berardius minimus
Yamada et al., 2019
NE Unknown (cetacean needed)
Genus Tasmacetus – one species
Common name Scientific name Status Population Distribution Size Picture
Shepherd's beaked whale Tasmacetus shepherdi
Oliver, 1937
DD IUCN Unknown [ad]    
2-2.5 tonnes
(cetacean needed)
Genus Ziphius – one species
Common name Scientific name Status Population Distribution Size Picture
Cuvier's beaked whale Ziphius cavirostris
G. Cuvier, 1823
LC Unknown [ae]    
2–3 tonnes
 
Subfamily Hyperoodontinae – three genera, 17 species
Genus Hyperoodon – two species
Common name Scientific name Status Population Distribution Size Picture
Northern bottlenose whale Hyperoodon ampullatus
Forster, 1770
DD IUCN 10,000 [af]    
7 tonnes
 
Southern bottlenose whale Hyperoodon planifrons
Flower, 1882
LC IUCN 500,000    
6 tonnes
(cetacean needed)
Genus Indopacetus – one species
Common name Scientific name Status Population Distribution Size Picture
Tropical bottlenose whale Indopacetus pacificus
Longman, 1926
DD IUCN Unknown [ag]    
3,5-4 tonnes
(cetacean needed)
Genus Mesoplodon Gervais, 1850 – 15 species
Common name Scientific name Status Population Distribution Size Picture
Andrews' beaked whale Mesoplodon bowdoini
Andrews, 1908
DD IUCN Unknown    
1 tonne
 
Blainville's beaked whale Mesoplodon densirostris
Blainville, 1817
DD IUCN Unknown      
Deraniyagala's beaked whale Mesoplodon hotaula
P. E. P. Deraniyagala, 1963
DD IUCN Unknown (cetacean needed)
Gervais' beaked whale Mesoplodon europaeus
Gervais, 1855
DD IUCN Unknown    
1.2 tonnes
 
Ginkgo-toothed beaked whale Mesoplodon ginkgodens
Nishiwaki & Kamiya, 1958
DD IUCN Unknown    
1.5 tonnes
 
Gray's beaked whale Mesoplodon grayi
von Haast, 1876
DD IUCN Unknown    
1.5 tonnes
 
Hector's beaked whale Mesoplodon hectori
Gray, 1871
DD IUCN Unknown    
1 tonne
 
Hubbs' beaked whale Mesoplodon carlhubbsi
Moore, 1963
DD IUCN Unknown    
1.4 tonnes
(cetacean needed)
Perrin's beaked whale Mesoplodon perrini
Dalebout, Mead, Baker, Baker, & van Helding, 2002
DD IUCN Unknown  
1.3–1.5 tonnes
(cetacean needed)
Pygmy beaked whale Mesoplodon peruvianus
Reyes, Mead, and Van Waerebeek, 1991
DD IUCN Unknown    
800 kg
(cetacean needed)
Sowerby's beaked whale Mesoplodon bidens
Sowerby, 1804
DD IUCN Unknown    
1-1.3 tonnes
 
Spade-toothed whale Mesoplodon traversii, syn. Mesoplodon bahamondi
Gray, 1874
DD IUCN Unknown    
1.2 tonnes
(cetacean needed)
Stejneger's beaked whale Mesoplodon stejnegeri
True, 1885
DD IUCN Unknown    
1.5 tonnes
 
Strap-toothed whale Mesoplodon layardii
Gray, 1865
DD IUCN Unknown    
2 tonnes
 
True's beaked whale Mesoplodon mirus
True, 1913
DD IUCN Unknown    
1.4 tonnes
 

Superfamily Platanistoidea: river dolphinsEdit

River dolphins are five species of dolphins which reside in freshwater rivers and estuaries. They are classed in the cetacean superfamily Platanistoidea. Four species live in fresh water rivers. The fifth species, the La Plata dolphin, lives in saltwater estuaries and the ocean. However, it is scientifically classed in the river dolphin family rather than the oceanic dolphin family. All species have adaptations to facilitate fish catching: a long, forceps-like beak with numerous small teeth in both jaws, broad flippers to allow tight turns, small eyes, and unfused neck vertebrae to allow the head to move in relation to the body.

Family Iniidae: river dolphinsEdit

This family contains one genus of two species, although the Amazon river dolphin (I. geoffrensis) has been divided into three subspecies:

  • Amazon river dolphin – I. g. geoffrensis – Amazon basin population (excluding Madeira river drainage area, above the Teotonio Rapids in Bolivia)
  • Orinoco river dolphin – I. g. humboldtiana – Orinoco basin population
  • Bolivian river dolphinI. g. boliviensis – Amazon basin population in the Madeira drainage area
Genus Inia – two species
Common name Scientific name Status Population Distribution Size Picture
Amazon river dolphin Inia geoffrensis
Blainville, 1817
EN IUCN Unknown    
150 kg
 
Araguaian river dolphin[ah] Inia araguaiaensis
Hrbek, Da Silva, Dutra, Farias, 2014
NE Unknown  
Araguaian river dolphin in blue
 
150 kg
 

Family Lipotidae: baijiEdit

The family Lipotidae is another monotypic taxon, containing only the baiji. Fossil records suggest the dolphin first appeared 25 million years ago and migrated from the Pacific Ocean to the Yangtze River 20 million years ago.[18] The species was declared functionally extinct in 2006 after an expedition to record population numbers found no specimens.

Genus Lipotes – one species
Common name Scientific name Status Population Distribution Size Picture
Baiji Lipotes vexillifer
Miller, 1918
CR IUCN 0-13 [ai]    
130 kg
 

Family Platanistidae: South Asian river dolphinEdit

The Platanistidae were originally thought to hold only one species (the South Asian river dolphin), but based on differences in skull structure, vertebrae and lipid composition, scientists declared the two populations as separate species in the early 1970s.[19] In 1998, the results of these studies were questioned and the classification reverted to the pre-1970 consensus. Thus, at present, two subspecies are recognized in the genus Platanista, P. gangetica minor (the Indus river dolphin) and P. g. gangetica (the Ganges river dolphin).[20]

Genus Platanista – one species
Common name Scientific name Status Population Distribution Size Picture
South Asian river dolphin Platanista gangetica
Roxburgh, 1801
EN IUCN 1,100 [aj]    
200 kg
 

Family Pontoporiidae: La Plata dolphinEdit

The La Plata dolphin is the only species of the family Pontoporiidae and genus Pontoporia. These dolphins are known for their long beak in relation to their relatively small body size. They have a small geographic range and are mainly found in the waters along the east coast of South America. La Plata dolphins are exclusively marine organisms, however, they are grouped with river-dolphins due to the fact that they reside in the La Plata River which is a salt-water estuary. With their white or sometimes pale brown coloration, fishermen tend to call them "the white ghost", as they also tend to stray away from any human interaction. [21]

Genus Pontoporia – one species
Common name Scientific name Status Population Distribution Size Picture
La Plata dolphin Pontoporia blainvillei
Gervais & d'Orbigny, 1844
VU IUCN 4,000–4,500    
50 kg
 

See alsoEdit

FootnotesEdit

  1. ^ The Society for Marine Mammalogy considers Eden's whale a smaller morph of the more widespread Bryde's whale based on current research.[14]
  2. ^ As of August 2018, the Arabian common dolphin is considered a subspecies of the common dolphin by the Society for Marine Mammalogy[14]
  3. ^ As of August 2018, the Society for Marine Mammalogy considers the long-beaked common dolphin as an ecologically-induced form of the short-beaked dolphin based on molecular evidence. The Eastern North Pacific long-beaked dolphin population may be a unique species D. bairdii[14]
  4. ^ The total population is unknown but numbers in the hundreds of thousands
  5. ^ The only population estimate is of 38,900 individuals in the eastern tropical Pacific Ocean
  6. ^ Total population is not known. There are estimated to be in excess of 200,000 in the Southern Ocean. The North Atlantic population is not known
  7. ^ Total population not known. There are 150,000 individuals in the eastern tropical Pacific Ocean. There are estimated to be more than 30,000 animals in the western Pacific, off the coast of Japan
  8. ^ The population around the continental shelf of the United States has been recorded to be in excess of 60,000. In the Pacific, a census recorded 175,000 individuals in eastern tropical waters and 85,000 in the west. No global estimate of population exists
  9. ^ Total population unknown but thought to be locally common – it is the most common dolphin found around the Falkland Islands
  10. ^ Estimates of various stocks throughout the North Atlantic give an overall value into the high tens or low hundreds of thousands
  11. ^ Varying population estimates for areas around California and the North Pacific give a total of up to 400,000
  12. ^ Surveys suggest this is the most common dolphin off of Chilean waters
  13. ^ Local estimates include 70–80,000 in the Antarctic, 8,000 in the tropical Pacific (although tropical waters are not the orca's preferred environment, the sheer size of this area — 19 million square kilometres — means there are thousands of orcas), up to 2,000 off Japan, 1,500 off the cooler northeast Pacific and 1,500 off Norway
  14. ^ Estimates for eastern tropical Pacific are 45,000 and another recent survey estimates population to be 1,200 for the eastern Sulu Sea, no global estimate is known
  15. ^ The total population is unknown. The eastern Pacific was estimated to have in excess of 40,000 individuals and is probably the home of the largest grouping
  16. ^ As of August 2018, the Society for Marine Mammalogy does not consider the Burrunan dolphin a distinct species due to problematic methodology in the study proposing its classification. The organization recommends further study to determine its validity.[14]
  17. ^ There are estimated to be 40,000 individuals in the Beaufort Sea, 25,000 in Hudson Bay, 18,000 in the Bering Sea and 28,000 in the Canadian High Arctic. The population in the St. Lawrence estuary is estimated to be around 1000
  18. ^ Aerial surveys suggest a population of around 20,000 individuals. When submerged animals are also taken into account, the true figure may be in excess of 25,000
  19. ^ No global population estimates have been made. One survey estimated a population of about 11,000 in the eastern Pacific
  20. ^ No global population estimates have been made. One survey estimated a population of about 11,000 in the eastern Pacific
  21. ^ There is not enough data to place finless porpoises on the endangered species list
  22. ^ There are no good estimates of the animals' abundance. However a comparison of two surveys, one from the late 1970s and the other from 1999/2000 shows a decline in population and distribution
  23. ^ In China, they are endangered. Their propensity for staying close to shore places them in great danger from fishing
  24. ^ There are no quantitative data on abundance
  25. ^ Nothing is known of the abundance of this porpoise. It was the most commonly encountered species during preliminary beach surveys undertaken on Tierra del Fuego
  26. ^ The most recent estimate for the North Pacific and Bering Sea is 1,186,000
  27. ^ The total number of sperm whales throughout the world is unknown. Crude estimates, obtained by surveying small areas and extrapolating the result to all the world's oceans, range from 200,000 to 2,000,000 individuals
  28. ^ Arnoux's beaked whales seem to be relatively abundant in Cook Strait during summer
  29. ^ Virtually nothing is known about the abundance of Baird's beaked whales, except they are not rare as was formerly thought
  30. ^ Nothing is known about the relative abundance of this species or its population composition
  31. ^ Because of the difficulty of identifying the species the total global population is unknown
  32. ^ Total population is unknown but likely to be of the order of 10,000
  33. ^ A 2002 survey estimates there are 766 animals around Hawaii. No other population estimates exist for other locales
  34. ^ As of August 2018, the Araguaian river dolphin is not recognized by the Society for Marine Mammalogy, which cites small sample size[14]
  35. ^ A survey from November–December 2006 failed to find any individuals. Another survey, from 1997, counted only 13 individuals. In 1986, surveys estimated the number to be at about 300
  36. ^ Estimates give values of 1,100 Indus river dolphins and maybe as few as 20 Ganges river dolphins

ReferencesEdit

  1. ^ Jamieson, Barrie G. M. (2016-04-19). Miller, Debra L. (ed.). Reproductive Biology and Phylogeny of Cetaceans. Reproductive Biology and Phylogeny. 7. CRC Press. p. 111. ISBN 978-1-4398-4257-7.
  2. ^ Agnarsson, I.; May-Collado, LJ. (2008). "The phylogeny of Cetartiodactyla: the importance of dense taxon sampling, missing data, and the remarkable promise of cytochrome b to provide reliable species-level phylogenies". Mol Phylogenet Evol. 48 (3): 964–985. doi:10.1016/j.ympev.2008.05.046. PMID 18590827.
  3. ^ Price, SA.; Bininda-Emonds, OR.; Gittleman, JL. (2005). "A complete phylogeny of the whales, dolphins and even-toed hoofed mammals – Cetartiodactyla". Biol Rev Camb Philos Soc. 80 (3): 445–473. doi:10.1017/s1464793105006743. PMID 16094808.
  4. ^ Montgelard, C.; Catzeflis, FM.; Douzery, E. (1997). "Phylogenetic relationships of artiodactyls and cetaceans as deduced from the comparison of cytochrome b and 12S RNA mitochondrial sequences". Molecular Biology and Evolution. 14 (5): 550–559. doi:10.1093/oxfordjournals.molbev.a025792. PMID 9159933.
  5. ^ Spaulding, M.; O'Leary, MA.; Gatesy, J. (2009). "Relationships of Cetacea -Artiodactyla- Among Mammals: Increased Taxon Sampling Alters Interpretations of Key Fossils and Character Evolution". PLoS ONE. 4 (9): e7062. Bibcode:2009PLoSO...4.7062S. doi:10.1371/journal.pone.0007062. PMC 2740860. PMID 19774069.
  6. ^ "Cetacean Species and Taxonomy". IUCN-SSC: Cetacean Specialist Group. Retrieved December 14, 2015.
  7. ^ Beckman, Daniel (2013). "Conservation of Cetaceans". Marine Environmental Biology and Conservation. Jones and Bartlett Learning. p. 328. ISBN 978-0-7637-7350-2. 
  8. ^ Clover, Charles (2008). The End of the Line: How Overfishing is Changing the World and what We Eat. University of California Press. ISBN 978-0-520-25505-0.
  9. ^ a b "The IUCN Red List of Threatened Species". International Union for Conservation of Nature and Natural Resources. Retrieved 20 January 2015.
  10. ^ Karlsen, K. (1962). "Development of tooth germs and adjacent structures in the whalebone whale (Balaenoptera physalus)". Hvalrådets Skrifter: Scientific Results of Marine Biological Research. 45: 1–56.
  11. ^ a b c d e f g Martin, Dr. Anthony R. (1991). Whales and Dolphins. London: Salamander Books. ISBN 978-0-8160-3922-7.
  12. ^ Miyashita, T; Kato, H (1998). "Recent data on the status of right whales in the NW Pacific Ocean". International Whaling Commission. Cambridge, UK. Missing or empty |url= (help)
  13. ^ Goldbogen, Jeremy A. (2010). "The Ultimate Mouthful: Lunge Feeding in Rorqual Whales". American Scientist. 98 (2): 124–131. doi:10.1511/2010.83.124.
  14. ^ a b c d e "List of Marine Mammal Species and Subspecies". Society for Marine Mammalogy. May 2016. Retrieved 16 April 2017.
  15. ^ "Common Bottlenose Dolphin". WWF. Retrieved 2019-05-13.
  16. ^ Bjorge, Arne; A Tolley, Krystal (2008). "Harbor porpoise Phocoena phocoena". In William F. Perrin; Bernd Wursig; J. G.M. Thewissen (eds.). Encyclopedia of Marine Mammals. pp. 530–532.
  17. ^ Hoffner, Erik (2018-03-08). "Only 12 vaquita porpoises remain, watchdog group reports". Mongabay. Retrieved 19 April 2018.
  18. ^ Wang, Yongchen (2007-01-10). "Farewell to the Baiji". China Dialogue. Retrieved 2007-05-29.
  19. ^ Pilleri, G., Marcuzzi, G. and Pilleri, O., 1982. Speciation in the Platanistoidea, systematic, zoogeographical and ecological observations on recent species. Investigations on Cetacea, 14: 15–46.
  20. ^ Rice, DW (1998). Marine mammals of the world: Systematics and distribution. Society for Marine Mammalogy. ISBN 978-1-891276-03-3.
  21. ^ "National Marine Mammal Laboratory - La Plata Dolphins". Alaska Fisheries Science Center - NOAA Fisheries. NOAA Fisheries. Retrieved 18 March 2019.

Further readingEdit

External linksEdit