Girish Mahajan (Editor)

Rorqual

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Kingdom  Animalia
Order  Artiodactyla
Superfamily  Balaenopteroidea
Higher classification  Baleen whale
Phylum  Chordata
Infraorder  Cetacea
Scientific name  Balaenopteridae
Rorqual whaleopediaorganimalfundwpcontentuploads2013
Family  Balaenopteridae Gray 1864
Mass  Blue whale: 140,000 kg, Humpback whale: 30,000 kg
Lifespan  Blue whale: 80 – 110 years, Humpback whale: 45 – 50 years
Length  Blue whale: 25 m, Humpback whale: 13 m
Gestation period  Blue whale: 11 months, Humpback whale: 11 months
Lower classifications  Blue whale, Humpback whale, Fin whale, Balaenoptera, Common minke whale

Le rorqual commun


Rorquals /ˈrɔːrkwəl/ (Balaenopteridae) are the largest group of baleen whales, a family with nine extant species in two genera. They include what is believed to be the largest animal that has ever lived, the blue whale, which can reach 180 tonnes (200 short tons), and the fin whale, which reaches 120 tonnes (130 short tons); even the smallest of the group, the northern minke whale, reaches 9 tonnes (9.9 short tons).

Contents

Rorqual Petit rorqual Baleines en direct

Rorquals take their name from French rorqual, which derives from the Norwegian word røyrkval, meaning "furrow whale".

Baleine bleue et petits rorquals tadoussac


Characteristics

Rorqual 1000 ideas about Rorqual on Pinterest

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 and common minke whale, which have shorter grooves). These are understood to allow the mouth to expand immensely when feeding, "permitting them to engorge great mouthfuls of food and water in a single gulp". These "pleated throat grooves" distinguish balaenopterids from other whales.

Rorqual Rorqual UniWiki

Rorquals are slender and streamlined in shape, compared with their relatives the right whales, and most have narrow, elongated flippers. They have a dorsal fin, situated about two-thirds the way back. Rorquals feed by gulping in water, and then pushing it out through the baleen plates with their tongue. They feed on crustaceans, such as krill, but also on various fish, such as herrings and sardines.

Rorqual Rorqual in Warp Trot Line

Gestation in rorquals lasts 11–12 months, so that both mating and birthing occur at the same time of year. Cows give birth to a single calf, which is weaned after 6–12 months, depending on species. Of some species, adults live in small groups, or "pods" of two to five individuals. For example, humpback whales have a fluid social structure, often engaging behavioral practices in a pod, other times being solitary.

Rorqual Rorqual EVEWiki

The "minke" whale is allegedly named after a Norwegian whaler named Meincke, who mistook a northern minke whale for a blue whale.

Distribution and habitat

Rorqual Rorqual Whale Chart A5 card Camilla Seddon Art Originals Prints

Distribution is worldwide: the blue, fin, humpback, and the sei whales are found in all major oceans; the common (northern) and Antarctic (southern) minke whale species are found in all the oceans of their respective hemispheres; and either of Bryde's whale and Eden's whale occur in the Atlantic, Pacific, and Indian oceans, being absent only from the cold waters of the Arctic and Antarctic.

Most rorquals are strictly oceanic: the exceptions are Bryde's whale and Eden's whale (which are usually found close to shore all year round) and the humpback whale (which is oceanic but passes close to shore when migrating). It is the largest and the smallest types — the blue whale and Antarctic minke whale — that occupy the coldest waters in the extreme south; the fin whale tends not to approach so close to the ice shelf; the sei whale tends to stay further north again. (In the northern hemisphere, where the continents distort weather patterns and ocean currents, these movements are less obvious, although still present.) Within each species, the largest individuals tend to approach the poles more closely, while the youngest and fittest ones tend to stay in warmer waters before leaving on their annual migration.

Most rorquals breed in tropical waters during the winter, then migrate back to the polar feeding grounds rich in plankton and krill for the short polar summer.

Feeding habits

As well as other methods, rorqual whales obtain prey by lunge feeding on bait balls. Lunge feeding is an extreme feeding method, where the whale accelerates to a high velocity and then opens its mouth to a large gape angle. This generates the water pressure required to expand its mouth and engulf and filter a huge amount of water and fish.

Rorquals have a number of anatomical features that enable them to do this, including bilaterally separate mandibles, throat pleats that can expand to huge size, and a unique sensory organ consisting of a bundle of mechanoreceptors that helps their brains to coordinate the engulfment action. Furthermore, their large nerves are flexible so that they can stretch and recoil. In fact, they give rorquals the ability to open their mouths so wide that they would be capable of taking in water at volumes greater than their own sizes. These nerves are packed into a central core area that is surrounded by elastin fibers. Opening the mouth causes the nerves to unfold, and they snap back after the mouth is closed. According to Potvin and Goldbogen, lunge feeding in rorqual whales represents the largest biomechanical event on Earth.

Taxonomy

Formerly, the rorqual family Balaenopteridae was split into two subfamilies, the Balaenopterinae and the Megapterinae, with each subfamily contained one genus, Balaenoptera and Megaptera, respectively. However, the phylogeny of the various rorqual species shows the current division is paraphyletic, and in 2005, the division into subfamilies was dropped. The discovery of a new species of balaenopterid, Omura's whale (Balaenoptera omurai), was announced in November 2003, which looks similar to, but smaller than, the fin whale; individuals of this species were found in Indo-Pacific waters.

  • Family Balaenopteridae: Rorquals
  • Archaebalaenoptera
  • Balaenoptera
  • Fin whale, Balaenoptera physalus
  • Sei whale, Balaenoptera borealis
  • Bryde's whale, Balaenoptera brydei
  • Eden's whale, Balaenoptera edeni
  • Blue whale, Balaenoptera musculus
  • Common minke whale, Balaenoptera acutorostrata
  • Antarctic minke whale, Balaenoptera bonaerensis
  • Omura's whale, Balaenoptera omurai
  • Cetotheriophanes
  • Diunatans
  • Incakujira
  • Megaptera
  • Humpback whale, Megaptera novaeangliae
  • Parabalaenoptera
  • Plesiobalaenoptera
  • Plesiocetus
  • Praemegaptera
  • Protororqualus
  • Balaenoptera
  • Fin whale, Balaenoptera physalus
  • Megaptera
  • Humpback whale, Megaptera novaeangliae
  • Pterobalaena
  • Common minke whale, Pterobalaena acutorostrata
  • Antarctic minke whale, Pterobalaena bonaerensis
  • Rorqualus
  • Sei whale, Rorqualus borealis
  • Bryde's whale, Rorqualus brydei
  • Eden's whale, Rorqualus edeni
  • Blue whale, Rorqualus musculus
  • Omura's whale, Rorqualus omurai
  • References

    Rorqual Wikipedia


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