Do you know whales are genetically closer to hippopotamuses than any other mammals on Earth? They were separated about 40 million ago. Whales belong to the infraorder Cetacea, which is divided into two parvorders; Mysticeti (baleen whales) and Odontoceti (toothed whales). It also includes dolphins and porpoises.
Below, from dangerous orcas to perky bottlenose dolphins and near-extinct Vaquita, you will find some of the well-studied types of whales.
21. Bowhead Whale
The Bowhead whale | Image Courtesy: Kate Stafford
Scientific Name: Balaena mysticetus
Length: 14-18 meters
Weight: Up to 100 tonnes
Also known as the Arctic or polar whale, the bowhead whale has a distinctive bow-like jaw structure, hence the name. Bowheads have the largest mouth of any extant animal species, making them efficient filter-feeders.
Unlike most of the other whale species, bowhead whales do not feature a dorsal fin. Bowhead whales have an estimated lifespan of over 200 years, making them the longest-living mammals on Earth. Their population is prevalent throughout the Arctic and sub-Arctic waters.
20. North Atlantic right whale
Reconstruction of a North Atlantic right whale | Image Courtesy: Citron / CC BY-SA 3.0
Scientific Name: Eubalaena glacialis
Average Length: 16 meters
Weight: Up to 80 tonnes
The North Atlantic right whale is one of the three closely related whale species in the genus Eubalaena. They were once a preferred whaling target due to their slow speed and submissive nature. While the hunting activities have now ceased, unintentional vessel strikes, entanglements, and climate change remain some of the biggest threats to the survival of this species today.
The North Atlantic right whale is labeled as a highly endangered mammal species. Their total population is estimated to be around 400.
19. Amazon River Dolphin
A feeding Amazon river dolphin | Image Courtesy: Frank Wouters/Flickr
Scientific Name: Inia geoffrensis
Length: 2.5 meters
Weight: 185 Kg
The Amazon river dolphin is one of the only two known species of river dolphin (Family Iniidae) found in South America. While the exact population of the Amazon river dolphins is unknown, three subspecies have been identified that are located in different parts of the Amazon basin.
The largest size an individual of this species can reach is 2.5 meters and weigh as much as 408 lb (185 kg). Due to s*xual dimorphism, male Amazon river dolphins are 55 percent heavier and 16 percent longer than the female population. The dorsal and pectoral fins of this species are larger relative to their body.
The only other member of the river dolphin family is the Araguaian river dolphin. The species is nearly identical to their relatives, except they feature a dorsal ridge instead of a fin.
18. North Pacific right whale
Scientific Name: Eubalaena japonica
Length: 15-18 m
Weight: Up to 100 tonnes
The North Pacific right whale species is another member of the Eubalaena genus. Like its close relatives, this species features an overly arched jawline, callosities on its head, and lack a dorsal fin at its back.
Like its Atlantic cousin, the North Pacific right whale is an endangered whale species. A large chunk of their remaining population resides along the shores of Kuril Islands and in the Sea of Okhotsk.
Back in 2010, a team of researchers led by ecologist Brendan Kelly reported multiple cases of hybridization between closely related marine mammal species in the Arctic. One of them was a crossbred between the North Pacific right whale and bowhead whale reported in the Bering Sea.
17. Southern right Whale
Scientific Name: Eubalaena australis
Average Length: 15 meters
Weight: 80-90 tonnes
Unlike the other two right whale species, the Southern right whales are not threatened or endangered. According to the most recent estimates, the Southern right whale population is close to 10,000 individuals and is fairly widespread in the lower part of the Southern Hemisphere.
A unique behavioral trait of the Southern right whales is tail sailing (lifting the tail out of the water surface). Also, they are often attracted to passing ships and vessels and trail them over long distances.
16. Blue Whale
Image Courtesy: NOAA
Scientific Name: Balaenoptera musculus
Length: 29 meters
Weight: 173 tonnes
The Blue whale is one of the eight [and most prominent] species in the genus Balaenoptera. Once abundant in the world’s oceans, the blue whale species now have about 10,000-25,000 individuals remaining today.
About three subspecies of blue whale have been identified so far: B.m. musculus in North Atlantic and Pacific waters, B. m. intermedia in South Atlantic ocean, and B. m. brevicauda or Pygmy blue whale in the South Pacific and the Indian Ocean. They are the largest known animal species on Earth.
A study conducted by Stanford University researchers in 2019 found out that, in depths, a blue whale’s heart rate is as low as two beats per minute. At the surface, however, it is between 25 to 37 beats per minute. An adult blue whale’s tongue can alone weigh more than 2.5 tonnes. Like other filter-feeders, blue whales exclusively feed on Krill.
15. Fin Whale
Aerial view of a Fin whale | Image Courtesy: NOAA
Scientific Name: Balaenoptera physalus
Length: 25.9 meters
Weight: 74 tonnes
Fin whale or finback whale is the second-largest animal species on the planet after the mighty Blue whale. They are also fast swimmers with the highest recorded speed, close to 41 km/h. As a cosmopolitan species, the fin whale is found in every climatic region (except polar extremes).
While fin whales are usually recognized by curved dorsal fins and distinctive asymmetrical markings on the body, they are often misidentified as blue whales or sei whales.
14. Sei whale
A mother Sei whale with her calf | Image Courtesy: Christin Khan
Scientific Name: Balaenoptera borealis
Length: 19.5 meters
Weight: 28 tonnes
The Sei whale is a large whale species in the genus Balaenoptera (same as the fin whale). They are blueish grey in appearance and feature a pointed rostrum (front part of the whale’s mouth, including the jaw) and arched dorsal fin. Sei whales may often present with flesh wounds (white scars) all over their body. These scars are believed to be a result of “cookie-cutter” shark bites.
Sei whale populations have been subjected to multiple mass death events in the past. One such event occurred in June 2015, when about 337 dead whales were discovered in a remote area of Patagonia, Chile.
13. Antarctic minke whale
Antarctic minke whales | Image Courtesy: Jerzy Strzelecki
Scientific Name: Balaenoptera bonaerensis
Length: 8.6-11.9 meters
Weight: 10 tonnes
The Antarctic or southern minke whale is one of the smallest known baleen species, with the longest ever specimen recorded at 11.9 meters.
Due to their relatively small stature (meat quantity) and low oil yield, the Antarctic minke population was mostly neglected by whalers until most recently in the 21st century. It is now identified as a near-threatened species.
Although Antarctic minke whales are exclusively found in the southern hemisphere, multiple sightings have been reported north of the Equator.
12. Humpback whale
Humpback whale | Image Courtesy: NOAA/Louis M. Herman
Scientific Name: Megaptera novaeangliae
Length: 12-16 meters
Weight: 25-30 tonnes
The humpback whales are easily identified by their long pectoral fin and bulky body. As the only member of the genus Megaptera, humpback whales have other bodily attributes distinctive to them.
Humpbacks are very popular among whale watchers and enthusiasts due to their frisky surfacing behavior (spy-hopping, tail-slapping, etc.) and singing or vocalization.
Audio of a singing humpback whale
It is a cosmopolitan species (inhabits every ocean and major seas), and its estimated worldwide populations are close to 80,000.
11. Grey Whale
A gray whale showing its baleen
Scientific Name: Eschrichtius robustus
Length: 12-16 meters
Weight: 25-30 tonnes
The grey or grey back whale is the only extant species of genus Eschrichtius. As the name suggests, grey whales are dark grey in color and have numerous white spots all over their body.
The grey whales feature a slightly lifted midline known as the dorsal ridge instead of the dorsal fin. Their population is located in two pockets of the world; eastern North Pacific and western North Pacific.
In 2015, a grey whale traveled across the Pacific ocean, covering a record-setting distance of more than 22,000 km.
10. Hector’s Dolphin
Hector’s Dolphin | Wikimedia Commons
Scientific Name: Cephalorhynchus hectori
Length: 1.4 meters
Weight: 40-60 kg
Hector’s dolphin is one of the four [and the most prominent] dolphin species in the genus Cephalorhynchus. Not only are they the smallest, but also one of the rarest dolphins on Earth.
Identifying Hector’s dolphin is easy because of its distinctive, round dorsal fin. They are overall pale grey in appearance. The critically endangered Maui dolphin is a subspecies of Hector’s dolphin and is endemic to New Zealand.
9. Pygmy Killer Whale
Pygmy Killer whale | Image Courtesy: USCG
Scientific Name: Feresa attenuata
Length: 2 meters
As the name suggests, pygmy killer whales are a much smaller version of the killer whales, also known as Orcas. They are known to feed on small fish and even common dolphins. Apart from physical characteristics and a few behavioral traits, not much is known about this species.
Their range extends from about 35 degrees north to 35 degrees south. A large population of Pygmy killer whales inhabits in the Pacific between the coast of Japan and Hawaii.
8. Short Finned Pilot Whale
A Short-finned pilot whale | Image Courtesy: Martina Nolte/Creative Commons CC-by-sa-3.0 de
Scientific Name: Globicephala macrorhynchus
Length: 5.5 meters
Weight: 3,000 kg
The short-finned pilot whale is one of the two whale species of the genus Globicephala the other being the long-finned pilot whale (Globicephala melas). As the name suggests, both species are distinguished by the length of their flippers.
Short-finned pilot whales also have relatively smaller jaws and feature numerous white spots or scars all over the body. The shape of the dorsal fin may differ from one individual to another since it is determined by the individual’s age and s*xual orientation.
7. Killer Whale
Killer whales near Unimak Island, Alaska | Image Courtesy: NOAA
Scientific Name: Orcinus orca
Length: 6-8 meters
Weight: 6 tonnes
Killer whales, also known as orcas, are at the very top of the marine food chain. They are known to hunt other predatory species such as tiger sharks, great white sharks, and feisty leopard seals. They also prey on larger whales, including the sperm whale and grey whale.
The killer whale is a highly social marine animal bound by complex social structures. Individuals live in a matriline society in which they spend their entire life with their mothers.
6. False Killer Whale
A false killer whale pod | Image Courtesy: Juan Ortega
Scientific Name: Pseudorca crassidens
Length: 6 meters
Weight: 2,200 kg
The false killer whale got its name because of its skull, which is identical to that of killer whales. They are well known for their erratic behavior. There are reported instances of false killer whales approaching and offering fish to human divers. But on the other hand, they are also known to take fish off the nets and hooks forcefully.
False killer whales are highly sociable animals, often found traveling in large numbers. In a few cases, they are seen accompanying dolphins even from other species (mostly bottlenose). However, false killer whales are highly aggressive against most dolphin species.
5. Beluga Whale
Beluga whale in Atalanta Aquarium | Wikimedia Commons
Scientific Name: Delphinapterus leucas
Length: 5.5 meters
Weight: 1,900 kg
The beluga whale is a large and distinctive whale species. It is the only living species of the genus Delphinapterus. Beluga whales lack a dorsal fin and are entirely white (the only marine species known with this attribute). In front of their head is a large but deformable biosonar, which allows them to produce high-pitched clicks to navigate and find prey.
Belugas inhabit cold, arctic, and sub-arctic waters but are kept in aquariums across the world.
Image Courtesy: Dr. Kristin Laidre/NOAA
Scientific Name: Monodon monoceros
Length: 5.5 meters
Weight: 1,600 kg
Narwhal is a medium-sized whale species found exclusively in the Arctic waters. It is the only surviving species in the genus Monodon and part of the family Monodontidae, together with the beluga whale.
Narwhal males (in rare cases female) feature a long, spiral tusk, an extended tooth that can grow up to 10 ft in length.
Research has shown that the Narwhal tusk works as a sensory organ, with close to ten million nerve endings inside, that feeds them vital information about their immediate environment.
3. Sperm Whale
Mother and a calf sperm whale
Scientific Name: Physeter macrocephalus
Length: 16-20 meters
Weight: 41 tonnes
The sperm whale is the largest toothed whale and one of the three extant species of the sperm whale superfamily (Physeteroidea); the other two are pygmy sperm whale and dwarf sperm whale.
About one-third of the sperm whale’s body is composed of its head alone. Its brain is the largest known of any species in the entire animal kingdom.
Sperm whales are known to create several high-frequency clicks or vocalizations. The loudest sound that a sperm whale can produce is 230 dB at 15 kHz.
A sperm whale clicks at 205 dB
2. Bottlenose Dolphin
A common bottlenose dolphin
Length: 4 meters
Weight: 300 kg
The bottlenose dolphin is a common name for the three extant whale species of the Tursiops genus, namely, the common bottlenose, the Burrunan, and the Indo-Pacific dolphin.
Bottlenose dolphins are known for their cognitive abilities, such as mimicry and concept learning. Because of this and friendly nature towards humans, bottlenose dolphins are a common sight in aquarium shows worldwide.
Moreover, they are also trained by several nations’ military (the United States and Russia) to detect enemy divers and underwater mines.
Read: World’s Oldest Known Piranha-Like Flesh-Eating Fish
A vaquita | Image Courtesy: NOAA
Scientific Name: Phocoena sinus
Length: 1.35 m
Once thought to be extinct, the Vaquita or cochito is a species of porpoise (similar to dolphins) endemic to the Gulf of California. It is the world’s most endangered cetacean species known.
Vaquita porpoise is grey in appearance and features unmissable dark rings around their eyes. They usually swim at a slow pace and avoid any kind of human interaction. It is the only known porpoise species to inhabit warm waters.
Frequently Asked Questions
What are the two main types of whales?
Whales (infraorder Cetacea) can be divided into two large groups; baleen whales (Mysticeti), and toothed whales (Odontoceti).
Baleen whales are named so due to their characteristic baleen plates, a filter-feeding system located in their upper jaw instead of teeth. These plates are made of keratin, the very substance found in our hair, nails, and the outer layer of skin, and function like a sieve allowing baleen whales to filter plankton and other foods from water. Species such as blue whales, humpback whales, and gray whales are examples of baleen whales.
As the name suggests, the toothed whales have teeth as part of their feeding mechanism (instead of baleen). They also have only one blowhole at the top of their head rather than two in a V-shape, as seen on baleen whales. Odontoceti or toothed whales can be further classified into four groups – Delphinoidea, Lipotoidea, Physeteroidea, and Ziphoidea.
How many species of whales are there?
So far, around 93 species of whales have been identified, out of which 16 are baleen whales and more than 75 toothed whale species.
Which is the world’s rarest whale species?
According to the IUCN Red List of Threatened Species, about five species of whales are Critically Endangered, 11 species are Endangered, and seven species are Vulnerable to extinction. The five Critically Endangered species are the North Atlantic right whale, Rice’s whale, Atlantic humpback dolphin, and Vaquita.
Vaquita, the smallest of all known whale species, was once believed to be extinct. Today, only less than a dozen individuals are known to be alive. Not only is Vaquita the rarest whale species, but it is also considered the most endangered marine mammal in the world.