Balaenidae () is a
family
Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...
of
whale
Whales are a widely distributed and diverse group of fully Aquatic animal, aquatic placental mammal, placental marine mammals. As an informal and Colloquialism, colloquial grouping, they correspond to large members of the infraorder Cetacea ...
s of the
parvorder
Order () is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and recognized ...
Mysticeti
Baleen whales (), also known as whalebone whales, are marine mammals of the parvorder Mysticeti in the infraorder Cetacea (whales, dolphins and porpoises), which use baleen plates (or "whalebone") in their mouths to sieve plankton from the wate ...
(baleen whales) that contains mostly fossil taxa and two living genera: the right whale (genus ''
Eubalaena
Right whales are three species of large baleen whales of the genus ''Eubalaena'': the North Atlantic right whale (''E. glacialis''), the North Pacific right whale (''E. japonica'') and the southern right whale (''E. australis''). They are class ...
''), and the closely related bowhead whale (genus ''
Balaena
''Balaena'' is a genus of cetacean (whale) in the family Balaenidae. ''Balaena'' is considered a monotypic genus, as it has only a single extant species, the bowhead whale (''B. mysticetus''). It was named in 1758 by Linnaeus, who at the time con ...
'').
Taxonomy
*Family Balaenidae
**Genus ''
Balaena
''Balaena'' is a genus of cetacean (whale) in the family Balaenidae. ''Balaena'' is considered a monotypic genus, as it has only a single extant species, the bowhead whale (''B. mysticetus''). It was named in 1758 by Linnaeus, who at the time con ...
''
***
Bowhead whale
The bowhead whale (''Balaena mysticetus''), sometimes called the Greenland right whale, Arctic whale, and polar whale, is a species of baleen whale belonging to the family Balaenidae and is the only living representative of the genus '' Balaena' ...
, ''Balaena mysticetus''

**Genus ''
Eubalaena
Right whales are three species of large baleen whales of the genus ''Eubalaena'': the North Atlantic right whale (''E. glacialis''), the North Pacific right whale (''E. japonica'') and the southern right whale (''E. australis''). They are class ...
''
***
North Atlantic right whale
The North Atlantic right whale (''Eubalaena glacialis'') is a baleen whale, one of three right whale species belonging to the genus ''Eubalaena'', all of which were formerly classified as a single species. Because of their docile nature, their sl ...
, ''Eubalaena glacialis''

***
North Pacific right whale
The North Pacific right whale (''Eubalaena japonica'') is a very large, thickset baleen whale species that is extremely rare and endangered.
The Northeast Pacific population, which summers in the southeastern Bering Sea and Gulf of Alaska, may ...
, ''Eubalaena japonica''

***
Southern right whale
The southern right whale (''Eubalaena australis'') is a baleen whale, one of three species classified as right whales belonging to the genus ''Eubalaena''. Southern right whales inhabit oceans south of the Equator, between the latitudes of 20� ...
, ''Eubalaena australis''

Until recently, all right whales of the genus ''Eubalaena'' were considered a single species—''E. glacialis''. In 2000, genetic studies of right whales from the different ocean basins led scientists to conclude that the populations in the North Atlantic, North Pacific and Southern Hemisphere constitute three distinct species.
Further genetic analysis in 2005 using mitochondrial DNA and nuclear DNA has supported the conclusion that the three populations should be treated as separate species, and the separation has been adopted for management purposes by the U.S. National Marine Fisheries Service and the International Whaling Commission.
[National Marine Fisheries Service: Review of the Status of the Right Whales in the North Atlantic and North Pacific Oceans (2006)]
(PDF). Retrieved September 15, 2011.
The
cladogram
A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ...
is a tool for visualizing and comparing the evolutionary relationships between
taxa
In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...
. The point where a node branches off is analogous to an evolutionary branching – the diagram can be read left-to-right, much like a timeline. The following cladogram of the family Balaenidae serves to illustrate the current scientific consensus as to the relationships between the North Pacific right whale and the other members of its family:
Evolutionary history
Baleen whale
Baleen whales (), also known as whalebone whales, are marine mammals of the order (biology), parvorder Mysticeti in the infraorder Cetacea (whales, dolphins and porpoises), which use baleen plates (or "whalebone") in their mouths to sieve plankt ...
s belong to a monophyletic lineage of
Mysticeti
Baleen whales (), also known as whalebone whales, are marine mammals of the parvorder Mysticeti in the infraorder Cetacea (whales, dolphins and porpoises), which use baleen plates (or "whalebone") in their mouths to sieve plankton from the wate ...
. Mysticeti are large filter-feeding
cetacea
Cetacea (; , ) is an infraorder of aquatic mammals belonging to the order Artiodactyla that includes whales, dolphins and porpoises. Key characteristics are their fully aquatic lifestyle, streamlined body shape, often large size and exclusively c ...
ns that also include some of the largest animals on earth as well as some of the most critically endangered.
[''Kaliszewska, Z. A.J. SegerV. Rowntreeet al2005Population histories'' of right whales (Cetacea: Eubalaena) inferred from mitochondrial sequence diversities and divergences of their whale lice (Amphipoda: Cyamus)Molecular Ecology1434393456] Based on morphology and molecular data, four extant family-level clades are recognized within Mysticeti: Balaenidae (bowhead and right whales), Neobalaenidae (pygmy right whales), Eschirichtiidae (gray whales), and Balaenopteridae (rorquals).
Phylogenetic relationships of the mysticeti order remain unclear due to legal and logistical challenges.
However, recent morphological analysis, support Balaenidae as a monophyletic group that is the sister group to Neobalaenidae.
Description

Balaenids are large whales, with an average adult length of 15 to 17 metres (45–50 feet), and weighing 50-80 tonnes. Their principle distinguishing feature is their narrow, arched, upper jaw, which gives the animals a deeply curved jawline. This shape allows for especially long
baleen
Baleen is a filter feeder, filter-feeding system inside the mouths of baleen whales. To use baleen, the whale first opens its mouth underwater to take in water. The whale then pushes the water out, and animals such as krill are filtered by th ...
plates. The animals utilise these by
ram feeding
Aquatic feeding mechanisms face a special difficulty as compared to feeding on land, because the density of water is about the same as that of the prey, so the prey tends to be pushed away when the mouth is closed. This problem was first identifi ...
, swimming at or near the surface with their mouth open for minutes at a time, and straining food from the water, which they then scrape off the baleen with their tongues
– a feeding method that contrasts with those of the
rorqual
Rorquals () are the largest clade, group of baleen whales, comprising the family (biology), family Balaenopteridae, which contains nine extant taxon, extant species in two genus, genera. They include the largest known animal that has ever lived, ...
s and the
gray whale
The gray whale (''Eschrichtius robustus''), also known as the grey whale,Britannica Micro.: v. IV, p. 693. is a baleen whale that migrates between feeding and breeding grounds yearly. It reaches a length of , a weight of up to and lives between ...
.
Their diet consists of small
crustacean
Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...
s, primarily
copepod
Copepods (; meaning 'oar-feet') are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (living in the water column), some are benthos, benthic (living on the sedimen ...
s, although some species also eat a significant amount of
krill
Krill ''(Euphausiids)'' (: krill) are small and exclusively marine crustaceans of the order (biology), order Euphausiacea, found in all of the world's oceans. The name "krill" comes from the Norwegian language, Norwegian word ', meaning "small ...
.
Similarities in terms of physical appearances of jawlines and usages between balaenidae and
flamingo
Flamingos or flamingoes () are a type of wading bird in the family Phoenicopteridae, which is the only extant family in the order Phoenicopteriformes. There are four flamingo species distributed throughout the Americas (including the Caribbe ...
have been pointed as a result of possible
convergent evolution
Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last comm ...
.
Balaenids are also robustly built by comparison with the rorquals, and lack the grooves along the throat that are distinctive of those animals. They have exceptionally large heads in comparison with their bodies, reaching 40% of the total length in the case of the
bowhead whale
The bowhead whale (''Balaena mysticetus''), sometimes called the Greenland right whale, Arctic whale, and polar whale, is a species of baleen whale belonging to the family Balaenidae and is the only living representative of the genus '' Balaena' ...
. They have short, broad, flippers, and lack a dorsal fin.
All species are at least somewhat migratory, moving into warmer waters during the winter, during which they both mate and give birth.
Gestation
Gestation is the period of development during the carrying of an embryo, and later fetus, inside viviparous animals (the embryo develops within the parent). It is typical for mammals, but also occurs for some non-mammals. Mammals during pregn ...
lasts 10–11 months, results in the birth of a single young, and typically occurs once every three years.
Distribution

The four species of the Balaenidae are found in temperate and polar waters; ''
Eubalaena glacialis
The North Atlantic right whale (''Eubalaena glacialis'') is a baleen whale, one of three right whale species belonging to the genus ''Eubalaena'', all of which were formerly classified as a single species. Because of their docile nature, their sl ...
'' (North Atlantic right whale), ''
Eubalaena japonica'' (North Pacific right whale), ''
Eubalaena australis
The southern right whale (''Eubalaena australis'') is a baleen whale, one of three species classified as right whales belonging to the genus ''Eubalaena''. Southern right whales inhabit oceans south of the Equator, between the latitudes of 20� ...
'' (southern right whale), and ''
Balaena mysticetus
The bowhead whale (''Balaena mysticetus''), sometimes called the Greenland right whale, Arctic whale, and polar whale, is a species of baleen whale belonging to the family Balaenidae and is the only living representative of the genus '' Balaena' ...
'' (bowhead whale). Bowhead and right whales can reach up to 18 meters in length and over 100 tons at maturity.
Exploitation and conservation status
Members of Balaenidae can live over 70 years and were hunted extensively in the late 1800s for their blubber. Approximately 40% of right whales' body mass is blubber, and thus they were known as the "right" whale to kill.
[Eubalaena glacialis (Müller, 1776) North Atlantic right whale, Encyclopedia of Life, accessed 11-30-2015]
After death, the large blubber deposits caused right whales to float to the surface, which facilitated an easier oil harvest. With a population estimated at between 300-350 individuals,
the North Atlantic right whale is the most critically endangered great whale. The Northern Pacific right whale is also endangered with only about 500 individuals extant.
The Southern right whale (~7500 individuals in 1997) and the Bowhead whale (20,000 to 40,000) have made stronger recoveries since whale hunting was significantly curtailed by international agreement.
References
External links
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{{Authority control
Baleen whales
Mammal families
Taxa named by John Edward Gray