Information about baleen whales

The family Baleenidae is the largest family under the suborder Baleen whales, including two genera and a total of nine species of baleen whales. These include the blue whale, currently the largest animal in the world, with a maximum weight of more than 150 metric tons. The weight of the next two largest baleen whales often exceeds 50 metric tons. Even the smallest minke whale in this class can weigh up to nine metric tons. above.

Origin of the common name

Members of the rorqual family of baleen whales are usually collectively referred to as "rorquals" in English. This name evolved from Norwegian and originally meant "whale with deep grooves" ( furrow whale), this is because they have a common feature: there are many long groove-like skin folds from the chin to the navel, called the throat groove or ventral pleat, whose main function is to assist Eat. Gray whales, which belong to the same suborder of baleen whales, and some beaked whales, which belong to the suborder of toothed whales, also have a structure similar to the throat and ventral folds, but the former only have four simple folds, which is far away in number from the dozens to nearly a hundred of the baleen whales. The so-called "ventral fold" of the beaked whale is just a V-shaped groove on each cheek.

minke

Minke whale is usually called "minke" in English. The origin of this name may be related to Meincke, a Norwegian or German whaling gunner. It is said that he once During a whaling operation in the early 20th century, minke whales were mistaken for blue whales and killed; another theory is that the whaler thought they were too small to be caught, and "minke" was the joking name he blurted out at the time.

Distribution

The baleen whales are widely distributed in the seas of the world. Blue whales, fin whales, humpback whales, sei whales, and minke whales can be found in all oceans. The traces of Bryde's whales are more special. They seem to never appear in the cold waters around the Arctic or Antarctic, but stay in warm and tropical areas all year round. Most of the baleen whales in the family Baleen whales live in the open ocean and rarely come close to the coast. Bryde's whales and great fin whales are the only exceptions: the former can usually be found near the coast all year round, while the latter often approaches the coast during their annual north-south migration. .

Only the two largest and smallest species of the baleen whale family - the blue whale and the minke whale - swim to the cold waters of the extreme south of Antarctica. Fin whales generally stay away from the Antarctic ice sheet, while sei whales range further north. (In the Northern Hemisphere, due to the larger land area and stronger influence on climate and ocean currents, the above situation is less obvious.) Regardless of the type of baleen whale, generally speaking, larger individuals tend to approach the polar regions, while Younger whales tend to stay further south (or north).

Migration

Most baleen whales breed in warm and tropical waters during the winter and feed on abundant plankton and krill at the poles in the summer. For this reason, they must Make long-distance north-south migrations. Bryde's whales are the only exception among the baleen whales. They seem to have no clear division between feeding and breeding seasons, and some groups may not even be migratory.

Feeding methods

The feeding habits of various baleen whales are different. For example, blue whales only feed on krill, while Bryde's whales feed mainly on small fish. The feeding behavior of baleen whales is sometimes described as "gulper" because they eat by opening their mouths wide to swallow a large amount of seawater at once. At this time, they increase the volume of their mouths by expanding the ventral folds of their throat and then closing them. The mouth spits out the water, and the food contained in the seawater is blocked by the baleen and remains in the mouth.

There are three families of baleen whales in the world: right whales, gray whales and fin whales, with approximately 6 genera and 11 species.

Baleen whales are huge, with the smallest species being more than 6 meters long. There are no teeth in the mouth, and only degenerated teeth can be seen during embryonic development. However, there are 150-400 horny whiskers arranged in a comb-like arrangement from the palate to the pharynx on the left and right sides of the maxilla. The color, shape and number of whiskers vary from species to species and are one of the important basis for classification. There are two external nostrils located on the top of the head, which can spray out two jets of water when breathing. The skull is extremely large, reaching 1/3 of the body length in some species, and is symmetrical. Cervical vertebrae heal or separate. The sternum is small, with only 1 pair of ribs connected to the sternum, and the thorax is incomplete. No collarbone. The flippers generally have 4 fingers. There is a cecum in the digestive tract.

They mainly feed on small crustaceans such as krill, but some species also eat small schooling fish, as well as bottom-dwelling fish and shellfish.

There are not many species of baleen whales. There are 9 species found in China. China has discovered blue whales, fin whales, big-fin whales, right whales, gray whales, etc.