[Curiosities] About Swan

[Mindsphere.]

 

Swans are a genus of large waterfowl in the family Anatidae. They can be recognized by the curved neck (they have the largest number of cervical vertebrae of all vertebrates) and by the white plumage (or black for some species). In Romania there are 4 species: winter swan (Cygnus cygnus), summer swan (Cygnus olor) and little swan (Cygnus columbianus); The black swan (Cygnus atratus) is often found in our zoos.

Morphology:

The largest swan species are Cygnus buccinator, Cygnus olor and Cygnus cygnus, weighing over 15 kg. On average, the largest species is Cygnus buccinator, and it lives in North America. There are about 18,000 specimens in the wild. The second largest swan species is Cygnus olor. It lives in Europe and Central Asia, and was introduced to North America. There are about 600,000 specimens in the wild. The third species is Cygnus cygnus; There are about 180,000 specimens in the wild.

Coloration:

 

In the northern hemisphere, the plumage of swan species is pure white (with the notable exception of Cygnus atratus from Austria which is completely dark gray but is a locally adopted variety of Australian black swan), but southern hemisphere species have a mixed color, white and black. For example, the Australian swan known po[CENSORED]rly as the black swan (Cygnus atratus) is completely black except for the white feathers on its wings, respectively in South America, there is a species called the black-backed swan (Cygnus melancoryphus) which has a neck black.

The legs of all varieties are dark gray, except for two South American species that are pink. The colors of the beaks vary from intense dark yellow, even red, to black. Thus, four subarctic species have black beaks with different amounts of yellow, while the mute and the black-necked swan have red beaks, each with an outgrowth at the base.

Body composition:

The body of the swan consists of the head, trunk and limbs. The head has 2 eyes with 3 eyelids, a beak with 2 nostrils and 2 ears without flags. The trunk ends with a long, hard feathered tail. The forelegs (wings) serve in flight, and the hind legs (legs) are adapted to walking and are covered with a scaly skin, which shows their kinship with reptiles. They are short and have clawed fingers: 3 fingers pointing forward and one pointing back.

Feeding:

Swans feed on plants, algae, grass, roots, but sometimes also eat small aquatic creatures. Most birds do not have teeth, but swans have jagged beaks, with small sharp corners, with which they catch food.

Breath:

Respiration is pulmonary; the lungs are connected to 9 air sacs.

Circulation:

The circulation is double and complete. The heart has 4 chambers: 2 atria and 2 ventricles.

Propagation:

They multiply by eggs, which they hatch. The puppies are cared for by their parents.

 

Edited May 31, 2020 by YaKuZa--BoSs
Closed Topic/complete 1 day.