Delphinidae

The Delphinidae are marine mammal Odontocète S named Dauphin S and Orque S.

Like all the mammals, they are animals Homéotherme S (with hot blood) (35 to 36 °C). They are carnivorous and eat coastal fish, sardines and herrings, cuttlefish, shrimps, octopuses and sometimes even of other marine mammals (orcs).

Description

Morphology

The dolphin has a smooth and flexible skin. With its hydrodynamic fuselage, it is an animal endowed for the speed which can reach 45  km/h. Its length is of approximately 1,7  measure with 4  meters for a varying weight of 70 with 400  kilograms. Its rostre (the nozzle of the dolphin), enough length, is equipped with many teeth, small and pointed, which are used to catch its preys, but not with the mastiquer.
To the difference of fish, its tail propels the dolphin while moving from top to bottom. The skeleton of the dolphin shows that the fins are indeed the vestiges of hands and legs of quadruped.
The eyes of the dolphin, spaced, enable him to see as well on the sides as in top, bellow or behind, and this, as well under water as above, thanks to its capacity to deform its Cornée. On the other hand, its vision of face is bad, and it uses the echolocation then to locate itself. It is the melon, the lubricating part on the face of the animal, which enables him to emit and receive the ultrasounds which will make it possible the dolphin to locate the position its prey and its speed.
The “nose” of the dolphin, called vent , is located at the top of the rostre and is used to him to breathe and opens only when the animal is above water. With a breathing, the dolphin renews 90  % of the air of its lungs. The dolphins can plunge up to 260 meters of depth and to remain thus without breathing during nearly fifteen minutes but remain in general under water only during a few minutes before taking again their breathing. The breathing of the dolphin is an act volontaire.
As it does not have glands sudoripares, the dolphin evacuates heat through its fins, largely irrigated blood.
When he sleeps, the dolphin remains with 50  centimetres below surface and, automatically, it goes up every half-hour to take air. One sometimes thus sees it floating close to surface with a fin which exceeds water. Like the majority of the mammals, the dolphin dreams during its sleep.
The dolphin, that it is in absolute or comparison with its mass, has a brain much larger than that of the man. One could thus think that the dolphin is most intelligent of the animals. However, this conclusion is very fast and simplistic. The question of the intelligence of the dolphins is still prone to debates.
The dolphin can live up to 50 years.

Reproduction

The mammals as the dolphin carry udders (in furrows on the side of the belly) and are Vivipare S. The young dolphin reaches its maturity towards the age of 1 or 2 years. The couple of dolphin is permanent
Gestation is from 30 to 40 weeks, at the end which only one small is put at the world.
The small fate by the tail (to avoid swimming immediately) and can immediately swim.
The mother and its “touched” then take along immediately the small one to breathe on the surface. He will be nursed during 2 to 8 months, but from 1 week he will venture already all alone.

Chorology

Distribution

The dolphin is an animal which lives in salt water of all the moderate seas of the sphere, around the coasts, and which migrates to follow the fish benches.
It is a social animal which lives in herds of hundreds of individuals where côtoient the young people, the females and the males, but without hierarchical structure. The dolphin cooperates with the other members of the herd through its activities of hunting and play while communicating with them by ultrasounds. They do not give up their casualties and do not fight between them.

Predatory

The only natural predator of the dolphin is the Orque, which one is as delphinidé but much larger and powerful as the dolphin. There are however already several times deferred of the case of dolphins being organized to counter Requin S (in particular during the birth of small, of the females defend the mother against the sharks attracted by blood). Even sometimes the dolphins manage to kill the shark while swimming at high speed and striking the belly of the enemy with the rostre.
However, the largest predator of the dolphin remains always the man: with the Japan, Izi in the south of Tokyo where it is fished for consumption, or of course the island of Iki where it is regarded as a dangerous predator, or captured by one of the many drifting nets, especially those intended to capture the Thon S, and marginally the individuals captured to populate the Delphinarium S…

Systematic

Denomination and taxonomy

The name of the dolphin comes from the Greek delphis which means spirit of the sea and is dependant in the name of Delphes, even if it were the emblem of Corinthe. Already, in the Antiquity, the marine people lent multiple exploits like guiding to them the boats mislaid in the storm or saving the shipwrecked men…
The word Cétacé means, as for him, marine monster in Greek and the word Odontocète means Cetacea with teeth .

History of the dolphin

See also: History of the Cetacea

The dolphin is downward terrestrial mammals which ventured in the ocean: the mesonyx then the pakicetus and the prosqualodon .

Classification

Delphinidés count 32 different species. The vernacular names indicated below are the names generally used but there exist however many variations.

  • Subfamily Orcininae - Orcininés

    • Kind Orcinus
      • Orcinus orca - Orc
    • Kind Pseudorca
      • Pseudorca crassidens - Distorts orc

See too

Related articles

External references

External bonds

  • '' Delphinidae '' in Systema Naturae 2000
  • a site for the protection and the knowledge of the dolphins sailor
  • a site which explains the anatomy and the physiology of delphinidés the

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